March 2001

PETROLEUM ENGINES

APPLICATION andINSTALLATION GUIDE

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1414-00

CATERPILLAR® PETROLEUM ENGINEAPPLICATION AND INSTALLATION GUIDE

Table of Contents

Marketing Profit Center Locations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .4Design Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5

Serviceability . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .5Installation Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .6Long Term Storage . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .7

Petroleum Engine Selection, Ratings, and Configurations . . . . . . . . . . . . . . .8Petroleum Equipment Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .13Engine Packaging for Electric Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . .20

Petroleum Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .20Two-Bearing Generator Offshore Power Modules . . . . . . . . . . . . . . . . . .21Two-Bearing Generator Land Rig Power Modules . . . . . . . . . . . . . . . . . .23Auxiliary Service Single-Bearing Generators Without Bases . . . . . . . . . .25Equipment Mounting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .27

Engine Packaging for Mechanical Drives . . . . . . . . . . . . . . . . . . . . . . . . . .29Mobile and Service Rigs . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .30Clutches, Belt and Chain Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .35System Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .36Torque Converters, Transmissions . . . . . . . . . . . . . . . . . . . . . . . . . . . . .38Transmission and Torque Converter Ratings and Adaptation . . . . . . . . . .40Mud Pump Calculations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .41

Alignment and Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43General Alignment Information Defining Types of Misalignment . . . . . . .43Crankshaft Deflection Test . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .49Alignment of Two-Bearing Generators . . . . . . . . . . . . . . . . . . . . . . . . . .49Alignment of Close-Coupled Driven Equipment . . . . . . . . . . . . . . . . . . .55Alignment of Mechanical Drives . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .56Vibration . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .57Isolation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .61

Noise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67Definitions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .67TMI Data . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .71Noise Control . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .72

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© 1976, 1979, 1982, 1985, 2001 Caterpillar

Available electronically in the Technical Information section ofhttps://oilandgas.cat.com

Table of Contents

Governors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Speed Droop Governors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .77Isochronous Governors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .79Electric Load Sharing Governors . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .80Electronic Governing and Control System . . . . . . . . . . . . . . . . . . . . . . .84Generator Set Performance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .86

Cooling Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .89General Information and Cooling System Functions . . . . . . . . . . . . . . . .89Coolant Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .94Watermaker Installation Requirements . . . . . . . . . . . . . . . . . . . . . . . . . .98Interconnection of Engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .101Heat Exchanger Cooling Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102

Expansion Tanks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .107System Considerations . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .109Emergency Radiator Circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114

Radiators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .114Installation Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .117Radiator Performance Criteria . . . . . . . . . . . . . . . . . . . . . . . . . . . .118Jacket Water Heaters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .123Extreme Cold Weather Considerations . . . . . . . . . . . . . . . . . . . . . .124Sizing and Installing Radiators for EPA Certified Engines . . . . . . . .125Supplemental Radiator Design Criteria . . . . . . . . . . . . . . . . . . . . .125

Lubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130Lubricating Oil Requirements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .130Scheduled Oil Sampling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .132Lubricating Oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133Prelubrication . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .133Duplex Oil Filter System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134Remote Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134Tilt Angles . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134Supplemental Bypass Filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .134

Fuel Delivery System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136System Description . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .136Fuel System Attachments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .142Fuel Specifications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .143Crude Oil Fuel System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .147

Exhaust System . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .151Air Intake Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159

Engine Room Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .159Land SCR Rig Ventilation Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . .164Combustion Air Intake . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165Air Cleaners . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .165

Crankcase Ventilation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .168DC Power Systems Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .171

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Table of Contents

AC Power Systems Controls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .173Oilfield Instruments . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .177Shutoffs and Alarm Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .180Starting Systems . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184

Electric Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .184Air Starting . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .187Starting Aids . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .189

Electrolytic and Galvanic Activity Protection . . . . . . . . . . . . . . . . . . . . . .191Fuel Conservation on Petroleum Engines . . . . . . . . . . . . . . . . . . . . . . . .193Daily Engine Report . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .205Engine Support Systems Layouts . . . . . . . . . . . . . . . . . . . . . . . . . . . . .206Design Review Sheets . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .208

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MARKETING PROFIT CENTER LOCATIONSCAT POWER SYSTEMS NORTH AMERICA (PSNA)

CATERPILLAR AMERICAS CO. (CACo)701 Waterford Way, Suite 200Miami, FL 33126-4670Ph: (305) 476-6800Fax: (305) 476-6801

CATERPILLAR OF AUSTRALIA LTD.(CofA)1 Caterpillar DrivePrivate Mail Bag 4TullamarineVictoria 3043Australia

CATERPILLAR ASIA PACIFIC LTD.(CAPL)Singapore Branch7, Tractor Road, JurongSingapore 627968Republic of SingaporeP.O. Box 0520Jurong Town Post OfficeSingapore 916118Ph: 662-8333Fax: 662-8302

CATERPILLAR CHINA LIMITED (CCL)37/F., The Lee Gardens33 Hysan Ave.Causeway BayG.P.O. Box 3069Hong KongPh: (852) 2848-0333Fax: (852) 2848-0440

(852) 2848-0400(852) 2848-0236(852) 2848-0223(852) 2868-5435

CATERPILLAR POWER SYSTEMS INC.Sanno Grand Bldg., 8th Floor2-14-2 NagatachoChiyoda-Ku, Tokyo 100JapanPh: (03) 3593-3231Fax: (03) 3593-3238

CATERPILLAR S.A.R.L.76, Route de FrontenexP.O. Box 6000CH-1211 Geneva 6SwitzerlandPh: (22) 849 44 44Fax: (22) 849 45 44Tlx: 413323Cble: CATOVERSEA

NORTH CENTRAL REGION

330 S.W. Adams St., LD-LL30Peoria, IL 61602Ph: (309) 675-4605Fax: (309) 675-4303

NORTHEAST REGION

175 Powder Forest Dr.Weatogue, CT 06089Ph: (860) 658-3411Fax: (860) 651-4118Speed No.: *0-119

NORTHWEST REGION

12600 SE 38th St.Suite 205Bellevue, WA 98006Ph: (425) 865-0251Fax: (425) 865-0919Speed No.: *0-037

SOUTH CENTRAL REGION

8300 FM 1960 WestSuite 340Houston, TX 77070Ph: (281) 677-2525Fax: (281) 807-6535Speed No.: *0-112

SOUTHEAST REGION

7621 Little AvenueSuite 202Charlotte, NC 28226Ph: (704) 752-1321Fax: (704) 752-1316Speed No.: *0-120

SOUTHWEST REGION

1450 N. Tustin AvenueSuite 217Santa Ana, CA 92705Ph: (714) 560-4010Fax: (714) 835-2737Speed No.: *0-106

CANADIAN REGION

3700 Steeles Ave. WestSuite 902Woodbridge, ON L4L 8K8Ph: (905) 850-3655Fax: (905) 850-3661Speed No.: *7-25

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Following are installation requirements forCaterpillar Diesel Engines applied in petro-leum applications, except for 3600 Seriesengines.Reliability of machinery is a major factor affect-ing satisfactory performance.Machinery must be properly installed in an accept-able environment to achieve reliability.The installation plan must assure machinery willbe able to function in its environment.Caterpillar is not responsible for choice or per-formance of components mentioned herein thatare not manufactured or serviced by Caterpillar.“It is the installer’s responsibility to consider andavoid possible hazardous conditions which coulddevelop from the systems involved in the spe-cific engine installation. The suggestions providedregarding avoidance of hazardous conditionsapply to all applications and are necessarily of ageneral nature since only the installer is familiarwith the details of his installation. The sugges-tions should be considered general examplesonly and are in no way intended to cover everypossible hazard in every installation.”The engine installation should be designed andsized according to the requirements of the appli-cation. Engine installation layout is important forventilation, cooling and the filtering of dirt andsand from the air. Space must also be plannedfor auxiliary equipment. In addition, heat andnoise levels should be adequate for worker’scomfort and comply with local, state, marineclassification society or country codes. Consid-erations must be given to how the engine pack-age is delivered to the site, i.e. by crane or othermethods.

Multiple Use Facility

Drill rigs have auxiliary equipment such as boilerunits, compressors, etc. For this reason, it isimportant for the room to have ample space formaintenance and repair of all the equipment.

ServiceabilityAdherence to proper maintenance practices iscritical to engine or generator set reliability.Caterpillar publishes guidelines and service inter-vals for every engine and generator model.Reference should be made to these guidelines for

specific maintenance practices. However, theinstallation must be designed for ease of servic-ing to ensure adequate maintenance.

Lifting CapabilitiesThe room enclosures should have adequateclearance to allow lifting of the generator sets forrepair work, etc.

ClearancesThere are different types of clearances: overhead,side and front/rear.

Overhead Clearances

Overhead clearance is the clearance above theengine and generator. Special considerationshould be made for clearances above the muf-flers, exhaust stacks and cylinder heads to allowspace for maintenance work.

Side Clearances

In a single or multiple generator set application,there should be sufficient space between enginesfor drain carts, tool carriages and other equip-ment. As a rule, the space between enginesshould be equal to at least the width of the engine.

Front/Rear Clearances

The room should be designed to provide suffi-cient area in front for removing the radiator andcamshaft from the block in case of major over-hauls. In a similar manner, there should be suf-ficient space at the rear of the generator forremoval of the rotor.

AccessAccessibility is an important feature in any engineroom design. There will be periodic preventive maintenanceon the engine, so easy access should especiallybe provided to:• lube oil filters and drain plug• fuel and air filters• jacket water pump• turbocharger• heat exchanger

DESIGN CONSIDERATIONS

Routine Maintenance

Access should be available through the serviceentrance in the case of regular routine mainte-nance. The entrance should be designed to han-dle the removal of generator sets, parts, fluidsand tools. Maintenance personnel should be ableto pass through freely.

Major Repair

Rooms should be able to handle major repairs,which may involve weight and size constraints.

Service Convenience

Air

Air should be in sufficient supply for use with airtools as well as ventilation purposes.

Water

Water is an important resource for cooling pur-poses as well as for cleaning the room, engine,and hands.

Air Pressure

Doors

Air restrictions in enclosed engine rooms can cre-ate a pressure differential between the room andthe surrounding areas. A 1.02 psi (7 kPa) pres-sure differential can create a 3086 lb (1400 kg)force exerted on a 3.28 2 6.56 ft2 (1 2 2 m2)door (as pressure is equal to weight divided byarea). The door design and proper ventilationshould be taken into consideration when design-ing the room.

Air Velocity

While air temperatures must be controlled, airvelocities affect worker comfort. The typical airmotion conditions include:

Table 1. Conditions from air velocity

TemperaturesPre-Start

The engine should be equipped with startingcapabilities especially in cold conditions.Provisions such as jacket water heaters, batteryheaters, oil heaters, ether start aids and anti-freeze concentration must be planned for toensure proper starting. These measures are takenin cold ambient conditions.

Operational

In order to maintain temperature and prevent de-rating of the engine during operation, adequateair and coolant flow are necessary. Radiators, ifso equipped, provide cooling air for the room, aswell as the engine. Heat exchanger and remoteradiator cooling remove much of the heat fromthe room, but ventilation will still be necessaryfor radiant heat.

Installation Considerations

Handling

Lift Points

Lift points on drill rig power modules are impor-tant as they provide support to the equipmentwhen it is moved.

When lifting, all supporting members (chains andcables) should be parallel to each other and asperpendicular as possible to the top of the objectbeing lifted.

When it is necessary to remove a component onan angle, remember that the capacity of an eye-bolt is reduced when the angle between thesupporting members and the object becomesless than 90 degrees. Eyebolts and bracketsshould never be bent and should only be loadedunder tension.

To move only the engine, use the lifting eyes onthe engine itself.

To remove the generator only, use the lifting eyesthat are on the generator.

Center of Gravity (CG) Calculations

This information is important, especially whenthey are hoisted by overhead cranes. Compo-nents with a lower center of gravity have less ten-dency to tip over when lifted.

Air Velocity(fpm) m/min Conditions

50 15.2 Offices, seated worker100 30.5 Factory, standing worker150 45.7 Capture velocity, light dust200 61.0 Maximum continuous exposure

1300 396.0 Capture velocity, rain1 – 2000 306.0 – Maximum intermittent exposure

610.0

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Long Term Storage

Engine Storage

When an engine is not started for several months,the lubricating oil drains from the cylinder wallsand piston rings. Rust can then form on the cylin-der liner surface, increasing engine wear anddecreasing engine life.

To prevent excessive engine wear:

• Be sure all lubrication recommendationsmentioned in the Maintenance Scheduleintervals chart are completed.

• If freezing temperatures are expected, checkthe cooling system for adequate protec-tion against freezing. A 50/50 solution ofEthylene Glycol based antifreeze andapproved water will give protection to –33°F(–36°C).

If an engine is out of operation and if use of theengine is not planned, special precautions shouldbe made. If the engine will be stored for morethan one month, a complete protection proce-dure is recommended. Refer to SEHS9031,Storage Procedures for Caterpillar Products, formore detailed information on engine storage.

Your Caterpillar dealer will have instructions forpreparing your engine for extended storageperiods.

Generator Storage

When a generator is stored, moisture may con-dense in the windings. Use a dry storage spaceand space heaters to minimize condensation.

Removing Generator Moisture

Drying does not always produce desired results.It may be necessary for the generator to bedipped and baked by a qualified rebuild shop.

• Energize the space heaters in the generator(if equipped).

• Space heaters can be installed on genera-tors (see the Parts Manual). They warm thewindings to remove moisture. The heatersshould be connected at all times in highhumidity conditions, whenever the genera-tor is not running.

Refer to SEHS9124, Special Instructions, Cleanand Dry Gen Set, or contact your Caterpillardealer.

Open Storage of Generators

Test the main stator windings with a megohm-meter:

• before the initial start-up of the genera-tor set

• every three months* if the generator is oper-ating in a humid environment

• if the generator has not been run under loadfor three months* or more

*This is a guideline only. If the environment is extremelyhumid or salty, it may be necessary to perform the MeggerTest more frequently. Refer to one of the following publica-tions for Megger Test information:• SEBU6918, SR4B Generators and Control Panels Oper-

ation and Maintenance Manual*• SENR5359, SR4B Generator Service Manual

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PETROLEUM ENGINE SELECTION, RATINGS, AND CONFIGURATIONS

Petroleum Engine Selection

General

One of the major concerns in applying petroleumengines is proper application of engine horse-power to obtain desired performance, economicoperation, and satisfactory engine life. Successfulapplication of petroleum engines requires under-standing of power requirements, how engines arerated, applicable emissions requirements, andknowledge of the proper selection and use ofthese ratings.

Power Requirements ComparedWith Past Experience

Before selecting an engine model and rating,power demand must be analyzed. This is simpli-fied if experience is available with a similarmachine powered by an engine of known rat-ing and fuel rate performance. This experiencehelps decide whether the machine was under-powered, correctly powered, or overpowered.

Calculated Horsepower Demand

Machine load demand can be estimated mathe-matically when no actual machine experience isavailable. Using basic engineering principles onwork and energy and data on the type of task tobe accomplished, it is possible to convert allfunctions of a machine to torque demand andthen to power demand. Calculation may be theonly way available to estimate power requirementsat the start of a new machine design. Of course,this approach is accurate only if all factors areconsidered and assumptions are correct. Forapplications such as pumps or other continuousloads, where demand is known quite well, cal-culated values are quite accurate. In other appli-cations, actual demand can differ significantly.

Engine Measured Power Demand

Usually, the most practical way to assess powerdemand and engine capability is to make a selec-tion based on calculation or comparison with pastexperience and test it. There is no substitute fora rigorous evaluation of an engine in the machineor application. This provides final proof ofmachine performance acceptability, or it willidentify shortcomings in need of correction.

Horsepower, Torque, and Machine Productivity

To better understand torque and horsepower,consider that a very small engine can providesufficient torque for a very large machine if thereis enough speed reduction. But, although themachine could have sufficient torque, it wouldoperate at such a slow speed as to be unpro-ductive. Productivity of most machines is approx-imately proportional to horsepower input.

Horsepower is the time rate of doing work. Orrestated, horsepower is proportional to the prod-uct of torque times rpm. Some basic relation-ships are:

English units

bhp = T 2 RPM5252

T = 5252 bhpRPM

1 hp = 33,000 ft-lbmin

Where: T = Torque, ft-lbMetric units

bkW = T 2 RPM9537

T = 9537 bkWRPM

T = Torque, N•m

Torque Rise Effect on Performance

For equipment (such as a plunger pump) whichis capable of lugging the engine (i.e., applyingsufficient load to pull the engine speed downbelow rated speed at full throttle), it is importantto consider two other characteristics of engineperformance. These are torque rise and responseto sudden load change.

Torque Rise % = (Peak Torque) – (Rated Torque) 2 100

Rated Torque

Cat® Diesel Engines used in mechanical drivestypically provide high torque rise to perform wellin a wide variety of applications.

A torque curve is the graphical representation oftorque versus speed.

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Some modification to the torque curve of a non-certified engine is possible in those cases wherethis is required to achieve satisfactory machineperformance. Consult your engine supplier if thisneed exists.

If torque rise capability is higher than necessary,the machine driveline may be subjected to torquelevels which may shorten the life of gearing andbearings. For this reason it is sometimes desir-able to let the machine operator shift to a lowergear to increase engine speed instead of alwayslugging the engine without a gear change. So, thedecision to use an extra high torque rise enginemust also consider driveline capability. By con-trast, an engine with insufficient torque rise willseem weak and may even stop running beforethe operator has time to make a gear change.This is not acceptable either. The best compro-mise is to use enough torque rise to satisfymachine performance requirements, but not somuch that driveline life becomes unacceptable.

Devices such as blowers and centrifugal pumpscannot lug an engine because power demanddrops off faster than engine capability as speedis reduced. The amount of torque rise availablein these applications is generally meaninglessbecause torque rise is not required, except as itmay contribute to the ability to accelerate the load.

Generation sets are constant speed applicationsand do not need torque rise capability.

Response Effect on Performance

A naturally aspirated engine has the fastestresponse to sudden load increase becauserequired combustion air is immediately available.However, few naturally aspirated engines meetemissions requirements. They are also morecostly and heavy.

There is a momentary lag in the response of aturbocharged or turbocharged and aftercooledengine because it takes a moment for the turboto accelerate upon load increase. Progress in tur-bocharger development has produced smaller,faster responding turbochargers and, therefore,turbocharged engines which respond quicklyto sudden load increase. With steady loadand speed, turbo response is of no consequence.Air/fuel ratio controllers, also called smoke lim-iters, momentarily limit fuel delivery until suffi-cient air is available for combustion. They respondto inlet manifold boost pressure. The proper

air/fuel ratio setting provides optimum machineresponsiveness and acceptable level of transientsmoke for a particular application.

Adequate Machine Performance

Manufacturers and customers develop their ownideas of what constitutes adequate machineperformance. Insufficient power causes lowproductivity and user dissatisfaction. Excessivepower costs more to purchase, requires heavierdrive system components, and may reduceequipment life if the operator is careless. Theideal machine is responsive, productive, anddurable, satisfying the owner’s need for per-formance and overall value.

Tolerances

Actual engine power output may vary by up to±3% from nameplate value on a new engine.Similarly, where load demand of some work-pro-ducing device is published, the manufacturer’stolerance should be added to demand power ifpower needs are to be met in all cases.

Fuel Heating Value

Fuel heating value affects the ability to achieverated power output because fuel is delivered tothe engine on a volumetric basis. Allowanceshould be made for lower heat content fuel(higher API than standard) where the power levelis critical.

Fuel rates are based on fuel oil of 35° API {60°F(16°C)} gravity having an LHV of 18,360 Btu/lb(42,780 kJ/kg) when used at 85°F (29°C) andweighing 7.001 lb/U.S. gal (838.9 g/L).

Auxiliary Loads

In addition to the engine’s main load, allowancemust be made for engine-driven auxiliary loads.Extra loads imposed by a cooling fan, alternator,steering pump, air compressor, and hydraulicpump may represent a significant proportion oftotal engine power available.

After establishing main load power demand andadding all auxiliary power demands, some addi-tional power should be allowed for peak loads(such as grades and rough terrain) and reservefor acceleration, where applicable.

Engine Rating Conditions

Ratings are based on SAE 1995 standardambient conditions. Ratings are subject to ±3%Power Tolerance. Ratings are valid for air cleanerinlet temperatures up to and including 122°F(50°C).

Note: Horsepower shown on the performancecurve for generator set applications may beslightly below the advertised horsepower tomatch a generator nominal output.

Engine performance is corrected to inlet air stan-dard conditions of 29.31 in. hg (99 kPa) drybarometer and 77°F (25°C) temperature. Thesevalues correspond to the standard atmos-pheric pressure and temperature as shown inSAE J1995.

Performance measured using a standard fuel withfuel gravity of 35° API having a lower heatingvalue of 18,390 Btu/lb (42,780 kJ/kg) whenused at 84.2°F (29°C) where the density is7.001 lb/US gal (838.9 G/L).

The corrected performance values shown forCaterpillar engines will approximate the valuesobtained when the observed performance datais corrected to SAE J1995, ISO 3046-2 & 8665& 2288 & 9249 & 1585, EEC 80/1269 andDIN 70020 standard reference conditions.

Engine RatingsAnother concern in applying engines is the properapplication of engine power to obtain desired per-formance, economic operation, and satisfactoryengine life. Successful application of enginesrequires an understanding of how they are ratedand how to properly select and use these ratings.

Published ratings are representative statementsexpressing engine power and speed capabilityunder specific loading conditions. There are sev-eral ratings for each configuration of petroleumengine model.

Engine Capability Determines Ratings

Horsepower rating capability is determined byengine design. Combined capability and dura-bility of all engine components determine howmuch horsepower can be produced successfullyin a particular application.

Power Setting Determines Maximum Fuel Rate

Horsepower output of a basic engine model canbe varied within its design range by changing theengine fuel setting or speed setting. Both settingsaffect the engine’s maximum fuel rate and,therefore, the horsepower output capability.Thermal and mechanical design limits will not beexceeded if an appropriate engine and ratingis selected.

Caterpillar Ratings are Offeredin a 5 Tier Format

“INDUSTRIAL A” — CONTINUOUS RATINGS

— For heavy duty service when engine isoperated at rated load and speed up to100% of the time without interruption orload cycling.

— Time at full load up to 100% of the dutycycle.

— Typical examples are: pipeline pumping,well service mixing units.

“INDUSTRIAL B” — RATINGS(Mud Pump Service)

— For service where power and/or speedare cyclic.

— Time at full load not to exceed 80% of theduty cycle.

— Typical examples are: oil field mechanicalpumping/drilling, independent rotary drive,well service blenders, cementers.

“INDUSTRIAL C” — INTERMITTENT RATINGS(Hoisting Service)

— For service where power and/or speed arecyclic. The horsepower and speed capa-bility of the engine which can be utilizedfor one uninterrupted hour followed by onehour of operation at or below the “IND A” —Continuous power.

— Time at full load not to exceed 50% of theduty cycle.

— Typical examples are: off-highway truck,fire pump application power, blast holedrills, oil field hoisting, nitrogen pumping,well service kill pumps, cementers, electricdrill rig power (also called Prime power).

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“INDUSTRIAL D” — RATINGS

— For service where rated power is requiredfor periodic overloads. The maximumhorsepower and speed capability of theengine can be utilized for a maximum of30 uninterrupted minutes followed by onehour at “IND C” — Intermittent power.

— Time at full load not to exceed 10% of theduty cycle.

— Typical examples are: offshore cranes, firepump certification power, coil tubing units,offshore cementer.

“INDUSTRIAL E” — RATINGS

— For service where rated power is requiredfor a short time for initial starting or suddenoverload. For emergency service wherestandard power is unavailable. The maxi-mum horsepower and speed capability ofthe engine can be utilized for a maximumof 15 uninterrupted minutes followed byone hour at “IND C” — Intermittent poweror duration of emergency.

— Time at full load not to exceed 5% of theduty cycle.

— Typical examples are: oil field well servic-ing frac/acid pumping.

NOTE: APPLICATION EXAMPLES ARE FORREFERENCE ONLY. FOR EXACT DETERMI-NATION OF RATING TIER REFER TO SPECIFICAPPLICATION INFORMATION AND GUIDE-LINES IN TMI.

Life Related to Load Factor

Use of an oversized engine contributes to longerengine life because it runs at a lower overall loadfactor. It also provides quicker response to sud-den load changes. Load factor is the ratio of aver-age fuel rate to the maximum fuel rate the enginecan deliver when set at a rating appropriate for aparticular application. This value is expressed asa percent.

Factors Involved in Establishing a Rating

Some of the application conditions consideredby a manufacturer in determining a rating for anapplication are: load factor, duty cycle, annualoperating hours, historical experience at a par-ticular rating level, and expected engine lifeto overhaul.

Engine Determines Rating Validity

A properly maintained engine in actual use willdetermine whether a particular rating level isappropriate. Ratings which are validated byacceptable field experience are retained. Contin-uing engine development results in ongoingengine improvement and some increase in rat-ings may result from this process.

Engines are Developed forSpecific Rating Levels

Engines are designed and developed to producespecific power levels for particular applications.Subsequent lab and field experience confirmsrating validity. Increasing engine horsepowerbeyond approved levels to compensate forexcessive load is not acceptable. Excessiveengine wear or damage can result.

Rating Curves

Consult Technical Marketing Information (TMI)or Petroleum Engine Performance handbooks forrating curves which show available ratings at var-ious speeds for each model and configuration.Specification sheets also carry some of this infor-mation for preliminary sizing purposes.

Special Ratings

Most engine applications are well understood andutilize one of the above existing published ratingswhich have been confirmed by thousands ofhours of successful experience. However, occa-sionally, a unique application merits special rat-ing consideration because of unusually low loadfactor or unusually short life requirements. In thiscase, consult your engine supplier. Factory appli-cation engineers will require that a special ratingrequest data sheet be submitted for review beforea special rating can be considered for approval.Emissions certification regulations reduce thefeasibility of some special rating requests.

Altitude Derating

Each model and rating has established maxi-mum altitude capabilities for lug and nonlugapplications. For higher altitude operation, powersettings must be reduced approximately 3% per1000 ft. (305 m) above that rating’s altitude limit.Mechanically controlled diesel engines do notself-derate enough so that the fuel setting can beleft unchanged. If they are not reset to appropri-ate power levels, naturally aspirated engines may

smoke badly and turbocharged engines may suf-fer excessive thermal and mechanical loading,resulting in internal damage without giving exter-nal indication of distress. Engine derating curvesare contained in the TMI.

Actual Power Output Derivesfrom Load Demand

Regardless of engine rating (power and speedsetting), the actual power developed by anengine is determined by the load imposed bydriven equipment. For example, an engine set toproduce 500 hp (373 kW) will actually produceonly 40 hp (30 kW) if the driven load demandsonly 40 hp (30 kW). For this reason, average fuelconsumption indicates average load demand.Average fuel consumption also indicates loadseverity on the engine by comparing it with therated fuel rate associated with that rating. Whenthis ratio is expressed as a percent, it is calledload factor.

Engine ConfigurationsOn a given engine model, a power range capa-bility is created by providing different engineconfigurations such as naturally aspirated,turbocharged, and turbocharged-aftercooled.Some engines may have the aftercooler cooledwith engine jacket water (JWAC). Some enginesmay have the aftercooler cooled with a separatelower temperature fresh water circuit (SCAC).Some engines may have the aftercooler cooled inan air-to-air cooling device (ATAAC). Emissionsrequirements many times determine the type ofaftercooling used. Internally, these engines maydiffer significantly. Naturally aspirated enginesgenerally do not meet emissions regulations.

Increasing power output by injecting more fuelrequires additional air for complete combustionand internal cooling. This requires additionalmechanical strength of internal components andadditional design features such as oil jet coolingfor pistons. In any engine, the mass flow of airsupplied to each cylinder determines the amountof fuel which can be efficiently burned. The entireengine must be designed for strength and dura-bility at approved power levels.

Turbocharging, using energy from waste exhaustgas, provides an efficient means to increase airflow. The power rating of a turbocharged engineis usually limited by internal temperatures, tur-bocharger speed, and structural limits. Compres-sion of the air by the turbocharger increases airtemperature.

An aftercooler between the tubocharger andintake manifold cools the hot compressed air.This increases air density and allows more air tobe packed into the cylinder and more fuel to beburned. The rating is typically limited by internaltemperature limits, turbocharger speed, andstructural limits.

Because turbochargers and aftercoolers providemore air to the engine, the engine fuel rate canusually be increased to use this extra combus-tion air. As a result, engine component loadingor turbo speed become the limit on rating.Caterpillar Diesel Engines do not utilize turbos oraftercoolers as add-ons. Rather, engines aredesigned and developed in all aspects for thesehigher loading levels. Then they are testedthoroughly to assure long life and satisfactoryperformance.

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There are many different ways to transmit powerfrom rig engines to the mud pumps, rotary table,drawworks, and auxiliary loads. Representativeexamples are discussed in this section to definenomenclature of these various drives and enableproper application of engines with correct ratings.

The terminology discussed is representative, butrecognize that the petroleum industry does nothave complete agreement on nomenclature.

Petroleum drives will be discussed under the fol-lowing headings:

Mechanical Drives• Conventional Rig• Split Rig• Mobile Rig

Electric Drives• DC• SCR

Service Rigs• Cementing• Acidizing• Fracturing• Nitrogen Pumping

Mechanical DrivesMechanical drives may be either direct drive oruse a torque converter.

Conventional Rig

The most common rig is the conventional rig. Itmay also be called a compound rig, althoughcompounds may also be used with independentdrives, Figures 1.1 and 1.2. Clutches are betweenthe engines and compound with either directdrive or torque converter drive.

The drawworks/rotary table is on an elevatedstructure to provide ground clearance under therotary table for safety valves (blowout preven-ters). Rig engines are also elevated on a sub-structure. This simplifies power transmission tothe drawworks.

Engine outputs are connected together with thecompound. A number of clutches control powerdistribution. Normally, engines operate in com-pound while hoisting and separately when run-ning the rotary table and mud pumps.

The approved engine rating is the pumping anddrilling rating.

CONVENTIONAL RIG

Figure 1.1

PETROLEUM EQUIPMENT DESCRIPTION

MAST (DERRICK)

DRAWWORKS

SUBSTRUCTURE

MUD PUMPS

ENGINES

COMPOUND

TYPICAL CONVENTIONAL RIG

Figure 1.2

SPLIT RIG

Figure 1.3

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Split Rigs

Split rigs utilize independent drives to power thevarious pieces of drilling machinery, Figure 1.3.

The approved engine rating for independent mudpump application is the pumping and drillingrating. Hoisting ratings are approved for inde-pendent drawworks/rotary drive applications.(Pumping and drilling rating can be used if enginecommonality is desired.)

Independent rotary drives are sometimes usedwith conventional rigs. Pumping and drilling rat-ing is approved for this application.

AC auxiliary generator sets supply electricpower necessary on a mechanical rig. In thisapplication, prime power generator set ratingshould be utilized.

Auxiliary engines power such things as mudmix pumps, supercharger pumps, or air com-pressors. Depending upon the particular appli-cation, duty cycle, load factor, etc., either A, B,or C rating tier levels are applicable. Electricmotor drives may be used in place of auxiliaryengine drives.

Mobile RigsMobile units are defined as oil field drilling orworkover units permanently mounted on wheels.They are frequently called chassis or carrier units,self-propelled or trailer mounted. They are a ver-sion of the split rig. A workover rig performsunderground repair of an existing well. It may becalled a pulling unit when there is no provisionof rotating the tubing string.

Carrier DesignationsFigure 1.4 shows a back-in workover rig. It is rep-resentative of the workover rig carrier designa-tion. A drive-in carrier has the driver’s cab locatedat the hinge point of the derrick.

These rigs may also be trailer-mounted (notshown).

Figure 1.4

Mobile workover rig describes a truck or trailer-mounted unit used to pull rod and tubing from aproducing well. The unit consists of engine(s),transmission(s), and drawworks.

Additionally, some rigs include a limited rotarytable capacity for use during well bore cleanout,while drilling out plugs (packers), or limitedredrilling in an existing well. A workover rig is alsocommonly called a service rig.

Occasionally, a mobile workover rig includes achassis-mounted mud pump. This is required tokill a flowing well, provide circulation duringcleanout and while drilling out plugs, etc.Normally, a mobile workover rig will use an inde-pendent mud pump kill unit.

Mobile drill rig describes a truck or trailer-mounted unit used to drill a well. The unit consistsof engine(s), transmission(s), drawworks, androtary table.

Mud pumps are normally independent units.

The rig may even be used for both drilling andworkover, or the basic unit can be sold into eitherapplication. In such cases, the major differenceis depth capacity. A drawworks and derrick usedfor drilling (where heavy casing is handled) has asmaller depth capacity than when used for work-over (where lighter tubing or rods are handled).

Manufacturers’ sales specifications will state bothdrilling and workover depth capacities.“Depending upon power and derrick capacity,dual purpose rigs (workover/drilling) can drill tomore than 12,000 ft. (3600 m) and workover tomore than 20,000 ft. (6000 m).”

TRANSMISSIONENGINE

DRAWWORKS

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Figure 1.5

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Drive Train Configurations for Mobile Rigs

Figure 1.5 shows various drive trains. There is agreat variety, and the drawings are not all-inclusive.

If the unit is a trailer unit, the power system drop-box (K) and drive axle (J) are eliminated.

On the twin engine in-line, the two engines couldalso be offset from each other, or the rear engineelevated to eliminate the dropbox (C).

Rigs using only a torque converter behind theengine may have a drawworks with either a two-or three-speed transmission or high-low drumclutches.

Electric DrivesElectric drives are commonly SCR. Older DCdrives may still exist. The same engine ratingsare applicable to both drives. Both utilize DCmotors due to their high torque at 0 rpm and theirvariable speed characteristics. The drives differ inthe method used to produce DC power.

DC Drives (Figure 1.6)

DC generators supply power to DC motors. ADC control panel regulates the DC and providesmeans to connect the DC generators to variousDC motors (Motor Assignment).

As Figure 1.6 illustrates, different motor assign-ments are used when hoisting or pumping anddrilling.

A main and spare AC generator is required forauxiliary power. The AC generators could be sep-arately driven by smaller Caterpillar Engines.

Figures 4.19 and 13.1 are a representative dieselengine power modules for DC drives. The DCgenerator is at the rear of the engine and utilizesan AC blower for forced ventilation. Many ofthese DC rigs are being converted to SCR.

SCR Drives (Figure 1.7)

AC generators supply power to an ACswitchgear. AC power is then fed to the SCR(Silicon Controlled Rectifier) modules where theAC is rectified to DC. An integral DC controlpanel connects the SCR modules to various DCmotors (Motor Assignment).

As Figure 1.7 illustrates, different motor assign-ments are used when hoisting or pumping anddrilling.

Auxiliary AC power is normally supplied fromthe same generators. Utility transformers are nor-mally required as the AC generators are normally600V AC. 600V AC provides the most accept-able DC voltage, when rectified.

Figure 2.10 and 17.10 are representative dieselengine power modules for SCR drives.

Figure 1.6

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Figure 1.7

Some Electric rigs power variable frequency ACmotors instead of DC motors. This has no essen-tial change for the engine or generator construc-tion. If the variable frequency device is a “diodefront end” device, the AC generators do not haveto be oversized.

AC Generators for SCR DrivesSCR drives require special generators. The ratedvoltage is usually 600V AC (for both 50 and60 Hz). This voltage changes to 800V DC throughthe SCR system, to power the DC motors.Operating DC motors at variable speeds causesthe generator Power Factor to vary. For exam-ple, the drawworks go from 0 PF to 1.0 PF everyhoisting cycle. Operation of the mud pumps atlow strokes also causes a low PF.Accordingly, AC generators are oversized to 0.6or 0.7 PF to provide more generator amperecapacity. Testing of gen sets with oversize gen-erators is limited to the engine’s hp capacity.Testable capacity of the gen set is given by theequation: EkW = (bhp – rad fan hp) 2 Gen eff2 0.746.Additionally, the generator must be form woundto provide additional mechanical bracing of thegenerator winding. This bracing resists the forcescaused by current surges resulting from operationof the SCR controllers. Generator winding tem-perature rise design limit is also lowered to com-pensate for additional heating caused by theSCR load.

Undersized generators may cause circuit breakertripping or slower drawworks acceleration.

Service RigsService rigs perform well servicing. This broadcategory generally includes those oilfield activi-ties that provide underground repair or alterationof an existing well (workover) and technical wellservicing. Workover rigs are discussed under thesubject Mobile Rigs.

Technical well services provide support functionsto well drilling (cementing and logging) or pro-vide means to change productivity of under-ground formations (acidizing and fracturing).Technical well service rigs are not equipped todo mechanical work on a well.

Service rigs that utilize large engines are used toperform three distinct services: cementing,acidizing, and fracturing.

The unit consists of an engine(s), transmis-sion(s), and piston-type pump(s). Equipment isusually mounted on a commercial truck chassisor may be trailer-mounted.

Figure 1.8 shows an acidizing/fracturing unit. Acement unit is not illustrated but is similar exceptwith smaller engines.

Cementing is the process of pumping cementdown a well bore to anchor casing. Cementingcan be required several times during the drillingof a well.

19 LEBW1414-00

Acidizing is the process of pumping an aciddown the casing of a completed well into thedesired producing formation. Certain types ofrock can be dissolved by acid, and this dissolv-ing process creates channels by which hydro-carbons can more readily flow to the well bore.

Fracturing is the process of applying an ultra-high pressure [2,000-15,000 psi (13783-103448 kPa)] down the casing of a completedwell to a desired producing formation. This pres-sure fractures the rock and creates channels bywhich hydrocarbons can more readily flow to thewell bore.

Nitrogen pumpers can be used with fracturingunits. Nitrogen is used for foam-frac in formationsthat would be damaged by a large volume offracturing fluid. Nitrogen can also be used toremove the frac fluid from a well after the frac-turing operation. (The nitrogen expands onremoval of pump pressure.)

The same service rig may be used to acidize orfracture. This does require changing the fluid endof the pump to match various pressure and flowrequirements.

Cementing units normally are not used to acidizeor fracture, although the unit appearance is sim-ilar. Cementing units normally carry mixingequipment not found on acidizing/fracturing units.

Cementing a well requires less power [100-500 hp (75-373 kW)] than fracturing or acidizing[500-10000 hp (373-7460 kW)]. Cementing isthus usually done with trucks with two engines ofapproximately 400 hp (300 kW) each.

Fracturing and acidizing are usually performedby trucks that have a 1250-2250 hp (930-1575 kW) engine.

Multiple trucks are used for high power acidizingand fracturing operations.

Figure 1.8

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Properly designed power modules are essentialfor diesel electric drives. Power modules mustwithstand vibrations and maintain original align-ment under all operational and environmentalconditions. Misalignment can cause vibration andshorten the life of couplings and generatorbearings.

The major cause of misalignment is flexing of thebase due to weakness in design. Other causesare poor installation methods and incorrect align-ment procedures.

Petroleum BasesCaterpillar petroleum bases are designed to elim-inate frequent, periodic realignment. The follow-ing criteria has been met with properly installedCaterpillar bases:

A. Engine torque does not cause excessivemisalignment.

B. Substructure flexure during operation doesnot cause bending movement of the base.

C. The power module is able to withstandrough handling during transportation with-out permanently distorting the base andmisaligning driven equipment. Tip overangle of the Caterpillar petroleum land rigbase with engine-generator arrangementis a minimum of 42 degrees (.74 rad).

D. The petroleum base is free of torsional orlinear vibrations in the engine operatingspeed range.

One-Bearing and Two-Bearing Generators

Caterpillar offers different bases for single- andtwo-bearing generators. Whereas bases for two-bearing generators must be sturdy to providesupport and maintain alignment, the base on sin-gle-bearing generators can be lighter becausethe base does not have to withstand torque reac-tion. Bolting the generator stator housing to theflywheel housing eliminates the need for the oilfield base to absorb the engine’s driving torque,Figure 2.1.

Close-coupled two-bearing generators are likesingle-bearing generators in that torque reactionis taken through the flywheel housing.

The stationary frame of two-bearing drivenequipment tries to rotate with the engine crank-shaft. If the petroleum base were not rigidenough, engine torque would cause excessivebase flexing. Misalignment results, proportionalto load, which will not show up during a conven-tional static alignment check.

Bases for Two-Bearing Generator Drives

A Caterpillar petroleum base is a torsionally rigidstructure. Three-point suspension maintainsproper relationship and alignment of all equip-ment and, by isolating external forces, preventsengine block distortion.

TORQUE REACTION OF 1 BEARINGVS 2 BEARING GENERATOR

Figure 2.1

1 BEARING GENERATOR ORCLOSE-COUPLED 2 BRNG. GEN.

FLYWHEEL HOUSING TOGENERATOR BOLTED JOINT ABSORBS TORQUE REACTION

2 BEARING GENERATOR

BASE MUST MAINTAINALIGNMENT AGAINSTTORQUE REACTION

GENERATORMOVEMENT

CRANK ROTATION

ENGINEMOVEMENT

ENGINE PACKAGING FOR ELECTRIC DRIVES

21 LEBW1414-00

Alignment Responsibility

The Caterpillar base assures the user of one-source responsibility for both packaging andalignment.

Three-Point Mounting

The three-point suspension system must be usedas there is a possibility the substructure sup-porting the base can deflect due to externalforces or settling.

Three-point mounting isolates the unit from sub-structure deflection, thus maintaining proper rela-tionship and alignment of all equipment andpreventing engine block distortion. More thanthree mounting points can cause base distortion,Figure 2.2.

Objectionable vibration can occur in adjacentmachinery or structures if the power module isnot mounted on well supported structures or isnot anchored securely. In addition to the three-point mounting, vibration isolators may berequired to isolate objectionable vibrations.

Figure 2.2

Two-Bearing GeneratorOffshore Power Modules

The Caterpillar petroleum offshore base consistsof a base-within-a-base. The inner base is three-point mounted — with integral spring isolatorsand limit stops — to the outer base. The outerbase can be welded to the rig support structure.The inner base structure is not the same as enginerails used in other applications. See Figures 2.3and 2.7.

The other base must be supported by large gird-ers. The outer base can be welded or bolted tothe rig structure. Inadequate support may resultin power module vibrations, Figure 2.4.

SPRING ISOLATOR OUTER BASE INNER BASE

Figure 2.3

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Provision for High Tilt Angles

Engines on isolators have movement when sub-ject to high tilt angles. Repeat cycles may dam-age connections to engine such as exhaust orcoolant. If tilt angle is extreme, the power mod-ule could fall out of the vibration isolator.

To prevent these conditions, limit stops areincluded with each isolator, Figure 2.5.

To optimize sound isolation, spring isolatorsinclude a mounting isolation pad and specialwashers under the hold down bolt heads.

Figure 2.4

Figure 2.5

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Lift Requirements

Lifting of heavy power modules must be doneproperly to avoid damage or injury. Engine orgenerator lift points should not be used to lift theentire power module.

Figure 2.6 shows the decal included with eachpower module, showing proper lift methods.

Two-Bearing GeneratorLand Rig Power Modules

Caterpillar land rig base uses 18 in. (457 mm)wide flange beams. Available lengths of 25 ft. 9 in.,30 ft. 9 in., 40 ft. 9 in. (7.85 m, 9.37 m, 12.42 m)allow matching base length to equipment needs.

Alignment integrity is provided by using a base-within-a base design. Figures 2.8 and 2.9.

The 40 ft. 9 in. (12.42 m) base has no deckingprovided from rear of generator to rear of base.Customer-supplied auxiliary equipment is to bemounted here, necessitating customer-supplieddecking and reinforcement.

Figure 2.8

Figure 2.6

WARNING!IMPROPER LIFT RIGGING CAN ALLOWLOAD TO TUMBLE CAUSING INJURYAND DAMAGE

1. WEIGHT, CENTER SYMBOL LOCATION AND INSTRUCTIONS GIVEN HEREIN APPLY TO UNIT AS SHIPPED BY CATERPILLAR . WEIGHT kg ( POUNDS)

2. USE PROPER SPREADER BAR AS DESCRIBED , BECAUSE CENTER OF GRAVITY IS ABOVE BASE LIFT POINTS .

3. ATTACH TWO PROPER RATED CABLES FROM BASE LIFT POINTS TO SPREADER BAR .

4. POSITION SPREADER BAR OVER CENTER SYMBOL FOR LE VEL LIFT.

2438 mm (96 INCH)

MAX. 1524 mm(60 INCH)

MIN.

4W-1422 1

INNER BASE

OUTER BASESPRING ISOLATORFigure 2.7

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Three-Point Mounting

Three mounting points are built into the base,Figure 2.8. This maintains alignment of engine-generator on uneven surfaces and during mostrig moves.

Required site preparation is a level firm soilwhich may be planked or a concrete surface,Figure 2.9.

Rough handling may occur during rig moves.This requires that alignment should be checkedafter such rig moves.

Additionally, certain types of soil, such as fineclay, loose sand, sand near the ground waterlevel, or soil that is freezing or thawing, are par-ticularly unstable under dynamic loads. Looseplanking under the power modules may alsocause power module vibration.

Because ground conditions may vary from welllocation to well location, vibrations may resultwhich are not due to misalignment or unbalancedparts. Unstable ground, discussed above, maybe reacting to normal forces within the engine/generator combination, whereas at another welllocation no such reaction may occur.

See the section on Vibrations for further infor-mation.

Package Handling

Cable tow and lift ends are part of land rig base,Figure 2.10.

Cable wrap protection against sharp bends is pro-vided. Pipe end is above bottom of base to pro-tect cable from constant abrasion when skiddingon hard surfaces, Figure 2.10.

Figure 2.9

PLANKING OR CONCRETE

FIRMSOIL

CABLE LIFT PROVISION

AIR CLEANER

Figure 2.10

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Roof and Walkway

Roofs and walkway wings can be added by thecustomer for servicing and weather protection,Figure 2.11.

Width of the wings should suit the customer. Itshould be at least as wide as the radiator. All con-nections of the bracing to the base should avoidstressing or flexing the I-beam’s flange or verti-cal member.

Guard rails, cable runs, lighting, exhaust piping,etc., can be added according to customer prefer-ence. See Figures 10.2, 10.3, 10.4, and 10.5 foradditional details.

Figure 2.11

ENGINE

NON-SKIDDECKING

PLATE

TYPICAL LAND RIG BASE USAGEWITH WEATHER PROTECTION

ROOFBRACE

ADDEDWING

Auxiliary Service Single-BearingGenerators Without Bases

Caterpillar Engines equipped with mounting feet,similar to those shown in Figure 2.14, aredesigned to flex. Bolting the feet to the rig struc-ture provides proper mounting. Do not weld theengine to the rig structure.

Figure 2.12

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Figure 2.13

On larger Caterpillar Engines, engine rails areextended to mount the generator. These railsshould not be notched or the cross bracesremoved when generator interference is encoun-tered, Figures 2.12 and 2.13.

A single-bearing generator set is still subject tovibrations if bolted to an uneven base or onethat flexes.

NOTE: A one-inch block of flexible mountingmaterial may be used under each mounting loca-tion to provide sufficient clearance to isolate sub-base flexing. Several types of resilient padsisolate noise but not vibration. Some may evenamplify first order vibrations. As a general rule,resilient mounting pads should have at least0.250 in. (6.0 mm) static deflection; less thanthis results in reduced noise but little or no vibra-tion isolation. Consult the supplier for specificinformation.

When a generator set is installed on a base thathas a deck place surface, make sure the genera-tor set rests firmly on the base beams, Figure 2.14.

Mounting on the deck plate will cause consider-able vibration of the deck plate or other struc-tures on the base. This is true whether or nota generator base is under the generator set,Figure 2.15.

The preferred method of mounting is to providesteel pads between the generator base and base

DECK PLATE

BASE BEAMSFLEXIBLE MOUNT ATMOUNTING FEETON BASE BEAMSFigure 2.14

DECK PLATE

GENERATOR BASE

BASE BEAMSUNDER MOUNTING FEET

BASE BEAMSDO NOT BOLTDECK PLATE TO GENERATOR BASE

STEEL PADS TOPROVIDE CLEARANCETO DECK PLATEFigure 2.15

27 LEBW1414-00

beams. The deck plate should be cut out at thepad location. Pads eliminate contact with thedeck plate, reducing vibration transmission intothe base. The mounting recommendations ofFigure 2.15 also apply to engines with mountingrails, Figure 2.13.Other auxiliary equipment installed on the samebase as the engine may create vibrations. Recip-rocating air compressors are a frequent cause ofvibrations. These and other similar auxiliaryequipment should be mounted on isolators.Flexible connections should be used on com-pressor air lines, etc.

Equipment MountingMounting Engine to Base

The standard Caterpillar mounting channel orbox rails are required. They properly support andanchor Caterpillar 3508, 3512, and 3516 Vee-type Oilfield Engines, Figure 2.16. These rails,while rigid enough, flex slightly to isolate theengine block from deflection caused by shim-ming error or non-rigid mounting structure. Aproper engine mounting system helps ensuredependable performance and long life if all equip-ment is properly aligned.

Figure 2.16

Engine Construction

A Caterpillar Engine is built as a rigid structure.If the engine is mounted on a pair of longitudi-nal rails, the tops of which are in the same plane,the engine will hold its own alignment and allowall working parts to operate in the manner forwhich they were designed. If the engine is sub-jected to external forces, or is restrained from its

natural thermal growth, tolerances are greatlyaffected and could easily result in bearing orcrankshaft damage.The main structural strength of an engine is thecast iron block. The plate steel oil pan, whichsupports the engine, is a deep, heavy weldment.Lugs or brackets are welded to the sides of the oilpan and hold the engine to the standard mount-ing rails, Figure 2.16.

Expansion/Thermal Growth

Any engine will expand in length, width, andheight from cold start to operating temperature.THIS GROWTH MUST NOT BE RESTRAINED.(The effect of thermal growth on alignment willbe discussed later.) As engine temperatureincreases to operating level, the entire enginegrows in length due to thermal expansion.Cast iron has a coefficient of expansion of0.0000055, and that of steel is 0.0000063. Thismeans that the block of an engine 94 in.(238.8 cm) in length will grow 0.083 in.(0.212 cm) if its temperature is increased from50°F (10°C) to 200°F (98.8°C). Using 0.0000063as the plate steel coefficient of expansion, a steelweldment of 94 in. (238.8 cm) will grow 0.089 in.(0.226 cm) through the same temperature range.The small difference in growth between the blockand the lubricating oil pan is compensated for inthe design of the engine by making holes in theflange of the attached component (rails) largerthan the attaching bolts.A fitted bolt is installed at the right rear corner ofthe block to oil pan to provide a reference pointfor making alignment. Clearance between themounting bolts and the mounting rails to the basewill then allow slip to compensate for thermalgrowth.Engine mounting rails also increase in tempera-ture, but to a lesser degree. Therefore, as muchclearance is not necessary for the mounting boltsthrough the engine rails as would be predictedby engine growth.Diameter of the clearance-type bolts used betweenthe engine rails and base mounting blocks mustbe 0.06 in. (1.6 mm) less than the diameter ofthe holes in the engine rails. This clearance allowsthe engine mounting rails to grow without con-finement, Figure 2.17.

Figure 2.17

Chocks should not be welded against the frontof the engine rail. There must be a minimum of0.030 in. (0.76 mm) clearance between themand the engine rails to allow sufficient room forthermal growth.It is common marine practice to install a fittedbolt at the right rear corner of the engine mount-ing rail. This is not required with the Caterpillarbase-within-a-base design.

Mounting InstructionsThe engine and generator must be mounted andanchored according to the following rules. Failureto do so may result in reduced life or prema-ture failure.

Engine MountingThe following information applies to engines uti-lizing the 10 in. (254 mm) rails instead of thebase-within-a-base concept.1. No shimming is allowed between the engine

and engine channel or box rails.2. Four mounting blocks and shims are used

between the engine rail and the base-sup-porting member on two-bearing units. Thiseliminates the need to machine base-sup-porting pads, Figure 2.17. Use Grade 8 boltsand hardened steel washers.

3. Mounting blocks must be welded to the base-supporting members. Use only two mount-ing blocks on each side of the engine, one ateach end. This minimizes engine block bend-ing due to base bending. The engine shouldbe positioned before the blocks are welded.The engine will serve as an alignment fixture,and the blocks can be tack welded in place.

It may be necessary to remove the engine tofacilitate final welding. Figure 2.18.

Generator Mounting1. Mounting blocks are used between the gen-

erator mounting feet and base supportingmembers. This eliminates the need tomachine base supporting pads, Figure 2.19.One shim pack of approximately 0.030 in.(0.76 mm) to 0.060 in. (1.5 mm) is installedbetween each mounting block and generatorfoot at original installation to permit possiblereplacement of generator. Use Grade 8 boltsand hardened steel washers.

2. The mounting blocks must be welded to thebase supporting members. Use only twomounting blocks on each side of generator,one at each end. The generator should bealigned before the mounting blocks arewelded. The generator will act as an alignmentfixture to hold the mounting blocks in place.

3. Recheck alignment and add or remove shimsbetween the generator mounting feet andmounting blocks. See the section Alignmentfor alignment details.

Figure 2.18

Figure 2.19

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Figure 3.1

ENGINE PACKAGING FOR MECHANICAL DRIVES

Engine Supports

Two types of engine supports are used — mount-ing rails, Figure 3.2, and mounting feet, Figure 3.3.

Caterpillar 3508, 3512, 3516 (and some 3412)Vee-type Oilfield Engines utilize mounting rails.The standard Caterpillar mounting rails arerequired.

DO NOT USE FRONT RAIL RESTRAINT

CLEARAN CETYPE BOLTS

MOUNTING BLOCK (4) AND SHIMS

ALIGNMENT CHOCKS(REAR AND FRONTSIDE ONLY)

Figure 3.2

Mounting Engines to Rig

The proper engine mounting system helps ensuredependable performance and long life, if allequipment is properly aligned.

The engine should be mounted on a pair of lon-gitudinal beams, the tops of which are in thesame plane. If the tops of the beams are not flat,add sufficient shims between the engine mount-ing surface and mounting beams. Bolting enginesto an uneven surface can cause harmful distor-tions in the engine block, springing of the mount-ing beams, and high stress in welds or base metal.

Refer to section on crankshaft deflection testfor the means of assuring the engine block is notstressed.

Mounting blocks are not required under the cen-ter of the engine rail, Figure 3.2. A mount locatedthere will distort the block if the beams to whichthe rails are bolted bend.

Figure 3.3

The diameter of clearance-type bolts holding theengine rails or feet to the mounting blocks on theoilfield base must be 0.06 in. (1.6 mm) less thanthe diameter of the holes in the engine rails. Thisclearance allows the engine mounting rails or feetto grow without confinement, Figure 3.2.

Each engine or generator mounting bolt mustbolt through solid material, Figure 3.4. If a mount-ing bolt is overhung, it will cause distortion,Figure 3.5.

When engines are being installed for repower, thevertical distance from the crankshaft centerline tothe engine rails/feet may be different betweenold and new engines. Modifications to the longi-tudinal beams may be required to lower an

engine. The alternative of raising the compoundis normally more costly.

PROPER PRACTICE

Figure 3.4

IMPROPER PRACTICEFigure 3.5

Mobile and Service RigsEngine-Transmission Mounting

The chassis of mobile rigs have two long stringers.Frame flexing can occur due to off-highwayusage. Additionally, well site preparations maynot result in a flat operating surface. Service unitscan also have extreme frame flexing due to feed-back from the plunger pump.

These considerations require that some type ofthree-point mounting of the engine-transmissionpackage be utilized. It supports the engine at asingle point at the front (a minimal torsionalrestraint) and at two points (each side) on the fly-wheel housing. This system allows large amountsof rig frame deflection without undue stresses tothe mounting pieces or engine.

Front Support — Most mobile rig engines utilizethe mobile equipment engine configurations witha trunnion-type support, Figure 3.6. This is nota true trunnion support in that it cannot rotate.For this reason, the frame connection to the trun-nion must allow an engine rocking motion tooccur (minimal torsional restraint). The radiatorhas to be mounted separately on the rig chassis.

Some engine installations will require the widefront support of the standard industrial engines,Figure 3.3. To provide a single mounting pointat the front, this mount must be modified,Figure 3.10. The wide front support is used whereit is inconvenient to separately mount the radia-tor. It will also find usage on helicopter rigs wherethe engine and radiator weight is restricted.

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Rear Engine Mounts — Rear mounts support therear of the engine and most of the transmissionweight. Rear mounts also supply resistance tolongitudinal and torsional forces.

In addition, the transmission must be supportedso that the transmission causes no appreciablebending moment at the flywheel housing rearface. See the section Overhung Power Trans-mission Equipment for the method to calculatebending moment, Figure 3.12.

Certain transmissions provide mounting pads tosupport the rear of the engine and cause noappreciable bending moment at the flywheelhousing rear face. Using this mount, instead ofthe engine rear mounts and transmission mounts,eliminates the transmission bending force on theflywheel housing and need for the bases dis-cussed later in this section (assuming trunnionfront support). Approval from the transmissionsupplier should be received before this mount-ing is used.

Figure 3.6

Figures 3.7 through 3.11 illustrate the variousmounting concepts. They are all equally suitable,subject to the limitations discussed below.

Figure 3.7 illustrates the use of a base to supportthe engine, transmission, and radiator. This baseis mounted to the chassis at three points.

Figure 3.7

TRUNION FRONTSUPPORT

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Figure 3.9 is a modification of Figure 3.8. It showsa power package which can be moved by heli-copter. Such packages require rear engine feet forsupport whenever the transmission is removedfrom the engine for transportation.

Figure 3.8

Figure 3.8 illustrates tying together the trans-mission and rear engine supports with a shortbase. This base has two mounting points to thechassis. The front of the engine has a trunnionmount plus the radiator is not engine-mounted.

Figure 3.9

Figure 3.10 illustrates how to make a single-pointmount out of the wide front support. If space is nolimitation, the fabricated single-point mount couldattach to the bottom of the wide front support.

Figure 3.11 illustrates the overhanging weight ofthe transmission being supported on springs.Calculations are required to determine spring siz-ing. The use of springs is limited to trailer rigs orservice rigs. The trailer fifth wheel gives, essen-tially, a three-point mount during transit to min-imize deflection forces on the flywheel housing.

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Figure 3.10

Figure 3.11

Forces and deflections of all components of themounting system must be resolved. If the thirdmount is a spring, with a vertical rate consider-ably lower than vertical rate of the rear enginesupport, the effect of the mount is in a properdirection to reduce bending forces on the flywheelhousing due to downward gravity forces but theoverall effect may be minor at high gravity forcelevels. Supports with a vertical rate higher thanthe engine rear mount are not recommendedsince frame deflections can subject the enginepower transmission equipment structure to highforces. Another precaution is to design the sup-port so it provides as little resistance as possibleto engine roll. This also helps to isolate the engine/transmission structure from mounting frame orbase deflection.

Overhung Power Transmission Equipment

Power transmission equipment, which is directlymounted to the engine flywheel housing, mustbe evaluated to ensure the overhung weight iswithin tolerable limits of the engine. If not, ade-quate additional support must be provided toavoid damage.

CAUTION: Mobile applications require consider-ation of dynamic bending movement imposedduring normal machine movement or abruptstarting and stopping.

The dynamic load limits and the maximum bend-ing moment that can be tolerated by the flywheelhousing can be obtained from your CaterpillarEngine supplier (source Caterpillar TechnicalMarketing Information) [TMI].

For determination of the bending moment ofoverhung power transmission equipment instal-lations, see Figure 3.12.

To compensate for power transmission systemswhich create a high bending moment due tooverhung load, a mount as shown in Figures 3.7,3.8, 3.9 or 3.10 is required.

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Figure 3.12

Clutches, Belt and Chain DrivesClutches

Both plate-type clutches and air clutches areused. Plate-type clutches are primarily used todrive small pumps and compressors. Enginesdriving mud pumps, drawworks, or a rotary tablenormally use air clutches.

Cyclic loading greatly affects clutch sizing.Centrifugal pumps cause no cyclic loading whileduplex mud pumps cause the greatest amount.Consult the clutch manufacturer to determineapplicable clutch load factors.

Plate-type clutches can operate with a limitedamount of side load. Clutch supports or pillowblock bearings allow greater side loads. Suchsupports or bearings must be mounted on thesame skid as the engine, Figure 3.13.

CLUTCH SUPPORTS

Figure 3.13

Excessive side loading of plate-type clutches cancause the driven plates to rotate off-center withthe drive plates. The result is destruction of theteeth and failure of the clutch plates. Running theengine without the clutch engaged (for long peri-ods of time) can damage the clutch pilot bearing.

Air clutches utilize an expanding air bladder forthe clutch element, Figure 3.14. The output shaftmust be supported by two support bearings. Airpressure to operate the clutch is supplied by anair connection through the drilled passage in theoutput shaft. Clutch alignment tolerances arereduced as air pressure to the clutch increases.

Auxiliary Drives

Engines on mechanical drill rigs are sometimescalled upon to drive one or more secondary loadsin addition to the primary load. These may bedriven from a front power takeoff, gear-drivenauxiliary drive, front crankshaft pulley, front stubshaft, or a rear-mounted power takeoff drivenfrom the top of some transmissions.

Auxiliary loads may be driven directly or indirectlythrough belt or chain drives. Those which aredirect driven may or may not require special cou-pling arrangements, depending upon torsionalcharacteristics of the total engine and load systemfor both ends of the engine. A torsional analysisis recommended to identify any destructive tor-sional criticals unless previous experience onidentical installations has proven the system safe.

Belt and Chain Drives

Belt and chain drives are generally free from tor-sional problems. Large input shafts, etc. maycause torsional problems, however. Belt andchain drives introduce side loads due to belt orchain pull plus tensioning forces. The larger thedrive pulley or sprocket, the greater the powerthat can be transmitted. Increasing drive pulley orsprocket diameter for any given side pullincreases the torque requirement of the drive.Consequently, shaft size, the drive’s bearing spac-ing and size, and capacity of the drive gears limitthe total horsepower the drive is capable of deliv-ering regardless of side load limitations.

It is important to remember that belt or chain ten-sioning must be added to the dynamic side loadwhen calculating the total. Failure to do this mayoverload bearings, chains, or belts and cause pre-mature failure. Follow recommended practiceson belt or chain tensioning as well as those forbelt or chain size and width.

Refer to the Technical Marketing Info (TMI) fordata on specific equipment.

Belt and chain drives may cause engine or drivenmachine to shift under heavy load due to torquereaction plus belt and chain preload tension. Beltsor chains may also cause the PTO (Power TakeOff) shaft or crankshaft to deflect which causesbearing failures and shaft bending failures.The driven sprocket or pulley should alwaysbe mounted as close to the supporting bearingas possible.

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Side load limits shown in TMI must not beexceeded. Sometimes, due to the heavy side load,it is necessary to provide additional support forthe driving pulley or sprocket. This can be doneby providing a separate shaft which is supportedby a pillow block bearing on each side of the pul-ley or sprocket, see Figure 3.14. This shaft canthen be driven by the engine or clutch throughan appropriate coupling.

The size of the driving and driven sprockets orpulleys is also important. A larger pulley orsprocket will give a higher chain or belt speed.This allows more horsepower to be transmittedwith less chain or belt tension. If it is suspectedthat an engine or the driven machine is shiftingunder load, it can be checked by measuring froma fixed point with a dial indicator while loading

and unloading the engine. Torque reactive vibra-tions or torque reactive misalignment will alwaysoccur under load.

System ConsiderationsSubstructure Suitability

Substructures must have sufficient strength andrigidity to support the weight of engines, com-pounds, etc., and withstand imposed vibrationsand torque from mud pumps and engines.

Lateral bracing provides resistance to sway,Figure 3.15. Pin joints should be tight. On olderrigs, it is sometimes necessary to repair wornpin joints.

Figure 3.15 illustrates that there should be noappreciable unsupported span of the compound

Figure 3.14

Figure 3.15

skid. Unsupported spans tend to allow the skidto sag, causing harmful vibrations.

Engine Spacing

Engine spacing is normally determined by thedistance between compound shafts.

Verify that using optional heavy-duty air clean-ers does not cause interference with machineryor restrict personnel movement. If necessary,brackets and piping can be fabricated to remotelymount the air cleaner.

Engine radiators may also interfere with otherradiators or restrict personnel movement. Radia-tors with the fan supported on the radiator canbe modified for right or left offset (as required).

Engine Operating Speeds

Most drilling contractors prefer to limit chainspeed to a given fpm (m/s) that gives a corre-sponding engine speed in the range of 1000 to1100 rpm, depending upon chain size and type.Torque converter drives usually can operate at1200 rpm.

Engines without torque converters must operateat this speed. It is recommended that the enginesbe set for this rated rpm to assure optimum per-formance, particularly under hoisting conditions.

Engine governor springs/settings and turbo-charger matches will have to be changed from the1200 rpm values when operating in the 1000 rpmrange, subject to engine certification limits. TheGovernor speed droop percent increases as theoperating speed is lowered. Improper springsresult in engines operating at a lower rpm whenswitching from mud pump to hoisting service —with a resulting lowered hoisting rate.

Proper turbocharger matches reduce fuel con-sumption, exhaust smoke and improve response.

An engine should be set, with proper governorsprings/settings and turbocharger, for the fullload operating speed and altitude.

Engine rated power changes as the rated speedis changed. Consult the appropriate specifica-tion sheet.

Above the engine altitude capability, improperturbo match can damage pistons and other com-bustion components. Consult the TMI for a spe-cific engine altitude capability.

Compound Ratio

The compound ratio refers to the ratio of the pul-ley/sprocket diameters that transmit power fromthe compound to mud pumps and drawworks,Figure 3.16. Changing one or both of these pul-leys or sprockets changes the operating speedof mud pumps and drawworks. The result is toreratio the compound.

Figure 3.16

It is important the compound ratio be such thatmud pumps’ and drawworks’ rated speed arereached with the engine at rated speed. Enginelife and performance are reduced when operatedwith high loads at low rpm.

If mud pumps are not operated at their ratedspeed, the compound ratio should be sized toallow the engine to operate at its rated speed.Either ratio selected should not allow either themud pump or engine to be overloaded.

During many repowers, the engines removedoperated at speeds (e.g., 900 rpm) which maybe below the chain speed limits. Under such con-ditions, the replacement engines can be oper-ated at a higher speed corresponding to the chainspeed limitation.

This higher speed may necessitate reratioingmud pump drives (changing the ratio), or theengines may have to be throttled back whenoperating the pumps. Verify engine overload doesnot occur when throttled back. The drawworksdrive may not have to be reratioed, with theresulting benefit of shorter trip time.

When new engines are replacing naturally aspi-rated engines in direct drive hoisting service,lower gear selections may be required. Never-theless, trip time is normally equal to or betterthan that with the original rig power.

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Three factors account for this:

• Once the engine accelerates, the hoisting speedis faster, provided the compound is operating ata higher speed than with the previous rig power.

• Engines with low torque rise may be able toaccelerate to rated speed when coming off theslips. However, they then may slow down con-siderably as layers of cable building up on thedrawworks drum increases line speed/engine loadand begins to lug the engine back. Cat Engineshave a high torque rise. This allows the draw-works transmission to be operated in a highergear with more weight on the hook than with lowtorque rise engines when hoisting the drill string.The engine is better able to maintain rated speedas layers of cable build up on the drawworksdrum. The remaining hoisting cycle is thus faster.

• If the compound is operating at a higher speedthan with the previous rig power, time will alsobe saved with the faster rate the empty blocksare lifted when tripping out.

In hoisting service, the heaviest drill string loadshould be able to be lifted in other than the low-est drawworks transmission gear under normalconditions.

Torque ConvertersWhen torque converters are used, the clutch isnormally on the torque converter output shaft.Clutch capacity has to be increased beyond adirect drive system.

Caterpillar Engines are compatible with rigs thatdo or do not use torque converters.

In hoisting service, engines without torque con-verters may require a lower gear selection thanengines with torque converters.

The use of torque converters increases the heatrejection to the engine radiator (up to 50%), gen-erally requiring oversized radiators.

Torque converter speed ratios are an importantconsideration. The torque converter output shaftspeed does not match engine speed. The approx-imate relationship of output shaft speed to enginespeed of a properly sized system is as follows:

Speed RatioTorque Converter Full Load No Load

1 Stage 80% 90-95%3 Stage 50-60% 90-105%

Type 4, 1 Stage 50-60% 90-105%

National and Allison torque converters are singlestage, Figure 3.17. Twin Disc and Allison Trans-missions use single stage torque converters.

The compound ratio must be selected accord-ingly. Engine throttle settings may have to bereduced during light load operation to preventoperating the compound chain above recom-mended speeds.

NATIONAL ALLISON

Figure 3.17

TransmissionsTransmissions fall into three broad classifications,all of which transmit power through sets ofmechanical gears, either spur or helical types, orplanetary designs. Where multi-speed capabilityis provided, it is accomplished either mechani-cally or automatically (hydraulically, pneumati-cally, etc.).

Due to the large number of transmissions com-mercially available, the transmission discussionwill be restricted to general operating principlesand considerations.

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When selecting a transmission, the packagedesigner must work closely with the transmissionmanufacturer.

CAUTION: REGARDLESS OF THE TYPE ORBRAND OF TRANSMISSION SELECTED, THEDESIGNER MUST ENSURE THAT IT HAS THECORRECT HORSEPOWER, TORQUE, ANDSPEED CAPABILITY TO MATCH THE DIESELENGINE PERFORMANCE CHARACTERISTICS.

Mechanical Transmission

The mechanical transmission provides the low-est cost method of providing multiple outputspeeds when the driven equipment input speedrange or torque requirements exceed the oper-ating capability of the diesel engine. Mechanicaltransmissions are usually equipped with sometype of clutch assembly to facilitate not onlyengine starting but also to change gear ratios.

Figure 3.18

This type of transmission is applicable to bothsemimobile and mobile installations where themomentary loss of power to the driven equip-ment when gear changes are affected does notpose operating problems. Generally, the mechan-ical transmission is employed when the gearspeed change requirements are not a constantrequirement and the speed shifts do not have tobe executed rapidly.

Today’s modern mechanical transmission, whenproperly matched to the engine-driven equip-ment, will provide reliable trouble-free service.Frequent gear changes, however, will accelerateclutch wear and maintenance costs.

Installation is simplified since mechanical trans-missions do not normally require oil cooling sys-tems as do the automatic types.

Automatic, Semiautomatic, andPreselector-Type Transmissions

As the names imply, these transmission typesaffect the gear changes either completely auto-matically or as predetermined by the machineoperator.

Engine power engagement/disengagementclutching is normally fully automatic and doesnot require the machine operator to physicallymove a clutch pedal or lever. For disengagementthe operator need only move the selector leverto a neutral position.

As with the mechanical transmission, the auto-matic type must be carefully matched to theengine operating horsepower, torque, and speedcharacteristics. However, with the automatictypes, additional match consideration may berequired since they normally utilize a torque con-verter, hydraulic coupling, or other type of non-mechanical engagement device for the powerengagement/disengagement function. This isnearly always accomplished hydraulically.

The automatic-type transmissions provide oper-ator ease of machine operation, as well as anearly constant power flow to the driven equip-ment during gear changes.

A number of commercial manufacturers offer awide range of automatic-type transmissions. Thepackage designer/installer must work closely withthe transmission supplier to ensure the trans-mission properly matches the machine applica-tion and provides the desired operating features.

Generally, the higher cost of an automatic trans-mission can be justified with a machine requiringhigh productivity and frequent load cycle changes.

When using automatic-type transmissions, otherinstallation considerations are required since mosttypes require a system to cool the transmissionoil. Caterpillar offers jacket water connections tosupply cooling water to customer or transmis-sion manufacturer-supplied heat exchangers.

Also offered are complete heat exchanger pack-ages on some engines, but care must be exer-cised to ensure that the Caterpillar system iscapable of handling the transmission heat rejec-tion. The cooling system capacity of the systemsoffered by Caterpillar can be obtained from yourCaterpillar Engine supplier.

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Engine Mounted Transmissions

Engine mounted automatic transmissions arecommonly used on workover and service rigs,Figure 3.19. Due to weight and space limitations,engine mounted transmissions are generally pre-ferred to drawworks mounted transmissions.

The most common transmission is a five or sixspeed power shift transmission with manual shiftcontrols. These transmissions have a built-intorque converter. The transmission is normallynot shifted on-the-go due to drawwork stress.Torque converters in these transmissions auto-matically lock up as the converter output shaftaccelerates to a set ratio of the engine speed. Asan engine is loaded and slows down, the trans-mission is adjusted to go back into converterdrive at about 100 rpm to 120 rpm above peaktorque rpm. Transmissions used with competitiveengine models are usually adjusted to return toconverter drive at higher engine rpms. Caterpillarrecommends that proper lock-up be used forCaterpillar Engines.

Rigs using only a torque converter behind theengine may have a drawworks with either a two-or three-speed transmission or high-low drumclutches.

Miscellaneous Considerations

When adding torque converters to an existing rig,or repowering with more powerful engines, it isnecessary to verify the compound, drawworks,and derrick assemblies can handle the increasedhorsepower or torque.

Normally, a clutch is required with torque con-verters and transmissions. Running only oneengine in a compound will rotate the output shaftof the other engine’s converter or transmissionand will damage the unit because the lubricationpump is normally driven off the input shaft.Contact the manufacturer regarding lubricationrecommendations when the output shaft is rotat-ing and engine is stopped.

Transmission and Torque ConverterRatings and Adaptation

Contact the respective manufacturers for infor-mation and performance curves not containedin this section, such as stall torque, etc.

Allison transmissions and torque converterscontain a flywheel as an integral part of their unit.

Caterpillar Engines require a Caterpillar optionalAllison adapter which includes a special flywheel.The Allison flex plates bolt to the Caterpillar fly-wheel. Access holes are provided in the flywheelhousing to give access to certain mounting bolts,Figure 3.20.

ALLISON

Figure 3.19

TWIN DISC

Figure 3.20

Allison transmissions and torque converters donot necessarily have the same engine adaptationeven though the same series designation is used.

Oil Coolers

Torque converters and/or transmissions rejectheat which must be removed. Commonly, thisheat is transferred into the engine cooling system.

Torque converter efficiency varies with theapplied load and may have a peak efficiencyof about 90%.

By convention, to allow operating tolerance, theheat load from torque converters is assumed tobe 30% of the engine bhp.

Transmissions, with lock up capability, areassumed to have a heat load of 20% of theengine bhp.

In either case, over heating can occur if the con-verter is loaded heavier than these assumptions.

Where available, the Caterpillar transmissiontorque converter oil cooler is sized for 70% con-verter efficiency. Actual heat rejection capacity isin the TMI. Customer flanges are included. Acooler connection group may be available if thecustomer desires to supply his own cooler.

NOTE: Other torque converters or transmissionapplications may require adaptation on the partof the dealer or OEM.

Torque Converter and Transmissionhp/kW Ratings

Contact the torque converter or transmissionsuppliers for their approved ratings.

NOTE: For convenience, transmission/torqueconverter manufacturers list their approved inputhp/kW as the equivalent without fan enginehp/kW that the engine is to be set for. Yet thesematches assume a net input hp/kW that includesnormal accessory losses. To these manufactur-ers, without fan hp/kW is a gross hp/kW thatexcludes normal accessory losses such as engineradiator fan and certain hydraulic pumps. Forproper transmission/torque converter rating for anonradiator-cooled application or an applicationwith extra auxiliary hp/kW loads, consult themanufacturer.

Use of Allison and Twin Disc transmissions forpumping and drilling applications is not antici-pated because the lower engine speed does notprovide for an optimum converter match.

Mud Pump CalculationsWhen sizing engines to drive mud pumps, severalcalculations may be required, depending uponthe extent of information available.

Mud pump input power (hpin) can be calculatedby the following formula:

hpin = psi 2 gpm = kPa 2 L/s____________ ____________1543 or 1457 671 or 634water or mud water or mud

1543/671 or 1457/634 reflect different volu-metric efficiencies.

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Determination of engine power requires additionof drive train power losses.

Engine hp = hpin + drive train hp losses

A reserve margin of 10% to 20% is commonlyadded.

Many times only the pump stroke speed is known.Gallons per stroke (liters per stroke) can bederived as follows: (volume per pump stroke, notvolume per pump piston stroke)

Triplex: (Dia)2 2 Stroke____________________97.9 424000English Metric

Duplex: (Dia)2 2 Stroke___________________ +147 63600English Metric

[(Dia)2 – (rod)2] 2 Stroke______________________________147 63600English Metric

(Dia = diameter of piston)

It is also useful to know the common operatingspeeds of mud pumps when sizing belt ratios:

Duplex: 40 to 65 strokes per minuteTriplex: 100 to 175 strokes per minute

Internal gear reduction ratios can be found inmanufacturer spec sheets or by inspection of themud pump, Figure 3.21.

Figure 3.21

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Improper alignment results in excessive vibra-tion, short life of generator/compound bearingsand coupling or clutch parts and a need for fre-quent realignment. Good alignment practicesinclude proper shimming, correct torque on hold-down bolts, accurate dial indicator usage,allowances for bearing clearances, thermalgrowth, and other characteristics of the engine.

CAUTION: BEFORE MAKING ANY ATTEMPTSTO MEASURE RUN OUT OR ALIGNMENT, IT ISIMPORTANT THAT ALL SURFACES TO BEMEASURED OR MATED BE COMPLETELYCLEAN AND FREE FROM GREASE, PAINT,OXIDATION, OR RUST AND DIRT — ALL OFWHICH CAN CAUSE INACCURATE MEA-SUREMENTS.

General Alignment InformationDefining Types of MisalignmentParallel Alignment

Parallel or bore misalignment occurs when cen-terlines of driven equipment and engine are par-allel but not in the same plane, Figure 4.1.

Figure 4.1

Checking Parallel Alignment

Parallel misalignment can be detected by attach-ing a dial indicator, as shown in Figure 4.2, andobserving the dial indicator readings at severalpoints around the outside diameter of the flywheelas the wheel holding the indicator is turned.

Figure 4.2

As a rule of thumb, the load shaft should indicateto be higher than the engine shaft because:

A. Engine bearings have more clearance thanmost bearings on driven equipment.

B. The flywheel or front drive rotates in a“drooped” position below the centerline ofrotation.

C. The vertical thermal growth of the engineis usually more than that of the drivenequipment. Engine main bearing clear-ance should be considered when adjust-ing for parallel alignment.

NOTE: Both parts can be rotated together ifdesired. This would eliminate any out-of-round-ness of the parts from showing up in the dial indi-cator reading. With non-Caterpillar couplings, therubber driving elements must be removed or dis-connected on one end during alignment sincethey can give false parallel readings.

ALIGNMENT AND VIBRATION

Angular Alignment

Angular or face misalignment occurs when cen-terlines of driven equipment and engines are notparallel, Figure 4.3.

Figure 4.3

Checking Angular Alignment

Angular misalignment can be determined bymeasuring between the two parts to be joined.The measurement can be easily made with afeeler gauge, and it should be the same at fourpoints around the hubs, Figure 4.4.

If the coupling is installed, a dial indicator fromone face to the other will indicate any angularmisalignment. In either case, the readings will beinfluenced by how far from the center of rotationthe measurement is made.

NOTE: The face and bore alignment affect eachother. Thus, the face alignment should berechecked after the bore alignment and vice versa.

After determining that the engine and load are inalignment, the crankshaft end play should bechecked to verify that bolting the couplingtogether does not cause end thrust.

Figure 4.4

Figure 4.5 illustrates that misalignment can occurin more than one plane. For this reason, alignmentreadings must be taken at 90 degree intervals asthe units are rotated when checking alignment.

BORE MISALIGNMENTUP/DOWN

BORE MISALIGNMENTRIGHT/LEFT

FACE MISALIGNMENTUP/DOWN

FACE MISALIGNMENTRIGHT/LEFT

Figure 4.5

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Inaccurate Flanges

Inaccurate flanges cause apparent misalignmentand make accurate alignment impossible.

Face runout refers to the distance the hub face isout of perpendicular to the shaft centerline,Figure 4.6.

Figure 4.6

Bore runout refers to the distance the driving boreof a hub is out of parallel with the shaft centerline,Figure 4.7.

Figure 4.7

The face and bore runouts of flywheel, clutch orcoupling, driven members, and hubs must bechecked when inconsistent alignment resultsoccur. Face or bore errors must be corrected.Bore-to-pilot diameter runout error should not bemore than 0.002 in. (0.05 mm) on the flywheeland 0.005 in. (0.13 mm) on adapters bolted tothe flywheel. Flange face runout should not bemore than 0.002 in. (0.05 mm).

Shimming

Shim packs under all equipment should be0.030 in. (0.76 mm) minimum and 0.125 in.(3.2 mm) maximum thickness to prevent latercorrections requiring removing shims when thereare too few or zero shims remaining. Excessivethickness of shims may compress with use.

Shims should be of nonrusting material. Handleshims carefully.

Engines and generators are recommended to usefour mounting feet. Before they can be aligned,each foot must be carrying its portion of the load.Failure to do this can result not only in misalign-ment, but also in springing of the substructure,high stress in welds or base metal, and high twist-ing forces in the engine or generator, Figure 4.8.

Figure 4.8

45 LEBW1414-00

Procedure for Tightening Engine andGenerator Mounting Bolts

After alignment, each mounting surface mustcarry its portion of the load. Figure 4.9 shows theprocedure used to verify proper shimming of gen-erator or engine has been accomplished. Whenthe proper number of shims has been established,add or remove shims evenly when making align-ment corrections.

Figure 4.9

Bolt Torque

A bolt is properly torqued when it is stretched acalculated amount. Proper stretch clamps thedriven device to the base securely. The clamp isthen maintained during movement caused byvibration. An undertorqued bolt cannot maintainclamping force while vibrations are present. It willgradually work loose and allow misalignment tooccur, Figure 4.10.

Bolts of the size used on Caterpillar oilfield basesrequire very high torque values. As an example,a 1 in. (25.4 mm) bolt has a torque of 640 ±80 ft. lbs (868 ± 108 N•m). A torque wrench,extension and torque multiplier are required toobtain this high value. Do not use special boltlubricants as the effective bolt clamping forcecan be excessive.

Caterpillar bolts are made of Grade 8 steel, one ofthe strongest available. They are identified by sixraised or depressed lines on the nut or bolt head.

Figure 4.9 shows the recommended torque forvarious Caterpillar bolts; however, these valuesmay be too high for standard commercially avail-able hardware.

Make sure mounting bolts are not bottomed outin hole, resulting in low effective bolt clampingforce. After completion of the final shimming andbolting operation, recheck the alignment.

Figure 4.10

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47 LEBW1414-00

Mounting Bolt Location

Each engine or driven equipment mounting boltmust bolt through solid material. If a mountingbolt is in an overhung condition, it will cause dis-tortion, Figure 4.11.

PROPER PRACTICE

IMPROPER PRACTICE

Figure 4.11

Dial Indicators

A dial indicator measures very small changes indistance. Alignment of shafting requires meas-urement of small changes in distance dimen-sions. The indicator must be rigidly located sothe specified alignment values can be measured.

Support Brackets

An indicator support bracket must rigidly sup-port the indicator when fixed to one of the shaftsand rotated. The support bracket allows locationof the dial indicator at the measurement point.Proper brackets can be adjusted to work withvarying driveline configurations, Figure 4.12.

Figure 4.12

Dial indicator brackets must not bend due toweight of the indicator. Commercially availabledial indicator brackets may not give adequatesupport when the indicator is rotated, causingfalse readings. Therefore, magnetic base dial indi-cator supports are not recommended.

To check support bracket rigidity, rotate the sameconfigurations of bracket and indicator through acircle while indicating on the bracket side of thecoupling. A maximum reading of less than0.001 in. (0.025 mm) is allowed. It may be nec-essary to temporarily bolt a very rigid referencearm onto the bracket side of the coupling for theindicator to read against to allow the same con-figuration of bracket and indicator, as when tak-ing an alignment reading.

Caterpillar recommends using the bracket,Figure 4.13, when performing alignment checks.Use two 0.50 in. (12.7 mm) diameter threadedrods or bolts to assemble the adapter. It may benecessary to fabricate different brackets whenchecking clutch alignments.

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Accuracy of Dial Indicator Readings

There is a quick way to check the validity of dialindicator face alignment readings. As Figure 4.14shows, readings are taken at four locations des-ignated as A, B, C, and D. When taking readings,the dial indicator should be returned to location Ato be sure indicator reading returns to zero.Values shown in Figure 4.14 are for a unit that isnot in alignment.

The quick check is to remember that reading ofB + D should equal C. (This is valid where driv-ing and driven shafts are rotated together whilechecking alignment.)

The quick check is useful for identifying improperprocedures such as: Sagging indicator brackets,dial indicator finger riding on flywheel chamfer, orindicator not properly positioned causing indi-cator to run out of travel.

Figure 4.14

IIIIIIIIIIIIIII I I I I I I I I I I I I I I I I I I I I I I I I I

IIIIIIIIIIIIIII I I I I I I I I I I I I I I I I I I I I I I I I I I I I

IIIIIIIIIIIIIIIII I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I

I

IIIIIIIIII I I I I I I I I I I I I I I I I I I I I I I I I I I I I I II I

I

D +10 –3 B

A

0

+7

C“B + D = C”

–3 + 10 = +7

Figure 4.13

Crankshaft Deflection Test3512 and 3516 Engines mounted on bases notsupplied by Caterpillar may require a crankshaftdeflection test. This applies to bases that supportthe engine at six or more points. Unevenness insuch a large number of mounting points canbend the engine block.

In contrast, the use of four mounting blocks can-not bend the engine block. Four mounting blockscan induce a twist in the engine block, but thiscannot be detected with a crankshaft deflec-tion test. See the section “Procedure for Tighten-ing Engine and Generator Mounting Bolts.”

This test can be performed on all Caterpillar Oil-field Engines equipped with crankcase inspectiondoors to assure the engine block is not undulystressed. It should be performed under cold engineconditions as this is the safest condition.

1. Remove an inspection door from the blockto expose the center crankshaft throw.

Rotate the crankshaft in the normal rotationdirection. When the cheeks of the centerthrow just pass the connecting rods, install aStarrett No. 696 distortion dial indicator orsimilar tool. As a precaution, tie a string tothe gauge and secure it outside the engineto facilitate retrieval should the assembly fallinto the oil pan.

Zero the dial indicator’s rotating bezel.Properly seat the indicator by rotating it on itsown axis until it will hold a zero reading.

2. With the indicator still set at zero, rotate thecrankshaft in the normal direction until theindicator nearly touches the connectingrods on the other side of the crankshaft. (Donot allow the indicator to touch the connect-ing rod.)

The dial indicator reading must not varymore than 0.001 in. (0.025 mm) through-out the approximately 300 degrees of crank-shaft rotation.

Rotate the crankshaft back to its originalposition in the opposite rotation direction.The indicator must return to its original read-ing of zero to make a valid test. If not, the indi-cator shaft points were not properly seatedand the test procedure must be repeated.

3. If the gauge reads more than 0.001 in.(0.025 mm), cylinder block distortion hasoccurred due to improper mounting.

Figure 4.15

Loosen the hold-down bolts between theengine rails and mounting blocks. Checkcarefully for loose shims, improper locationsof fitted bolts, interference from clearancebolts, or any other constraints to properengine block movement.

Make any needed adjustments and secure thehold-down bolts, making sure alignment ofthe engine has not been disturbed.

4. Repeat the distortion check procedure.Consult your Caterpillar dealer if the engineblock is still bent.

Alignment of Two-Bearing GeneratorsFactors Affecting Alignment

The input shaft of remote-mounted equipment isalways positioned higher than the engine crank-shaft. This compensates for vertical thermalgrowth, flywheel sag, and main bearing oil film lifton crankshaft. These factors cause the relativepositions of crankshaft and load input shaft toshift between static and running conditions.

49 LEBW1414-00

Bearing Clearances

The generator rotor shaft and engine crankshaftrotate in the center of their respective bearings,so their centerlines should coincide. Alignmentis made under static conditions while the crank-shaft is in the bottom of its bearings. This is notits position during operation. Firing pressures,centrifugal forces, and engine oil pressure all tendto lift the crankshaft and cause the flywheel toorbit around its true center, Figure 4.16.

Generally, driven equipment will have ball orroller bearings which do not change their rota-tional axis between static and running conditions.

Figure 4.16

Flywheel Sag

With the engine not running, the weight of theoverhanging flywheel and coupling causes thecrankshaft to bend. This effect must be com-pensated for during alignment since it results inthe pilot bore and outside diameter of the fly-wheel rotating lower than the true crankshaftbearing centerline during alignment. Caterpillarrecommends alignment checks be performedwith the coupling in place, Figure 4.17.

Figure 4.17

Torque Reaction

The tendency of the engine to twist in the oppo-site direction of shaft rotation and the tendencyof the driven machine to turn in the direction ofshaft rotation is torque reaction. It naturallyincreases with load and may cause a vibration.This type of vibration will not be noticeable at idlebut will be felt with load. This usually is causedby a change in alignment due to insufficient basestrength allowing excessive base deflection undertorque reaction load. This has the effect of intro-ducing a side-to-side centerline offset whichdisappears when the engine is idled (unloaded)or stopped.

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Thermal Growth

As engine and generator reach operating tem-peratures, expansion or thermal growth willoccur. This growth is both vertical and horizontal.

Vertical growth occurs between componentmounting feet and their respective centerlines ofrotation. This thermal growth depends on thetype of metals used, the temperature rise thatoccurs, and vertical distance from the center ofrotation to the mounting feet, Figure 4.18.

Vertical compensation consists of aligning equip-ment to a non-zero value, Figure 4.25.

Crankshaft horizontal growth occurs at the oppo-site end of the engine from the thrust bearing.This growth has to be planned for when drivenequipment is connected to that end of the engine.The growth is slight if the driven equipment isbolted to the engine block, since the block andcrankshaft grow at approximately the same rate,Figure 2.12.

Figure 4.18

Figure 4.19

HORIZONTAL THERMALGROWTH

COUPLING CLEARANCE

GENERATOR VERTICAL GROWTH

ENGINE VERTICAL GROWTH

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Horizontal compensation consists of using a cou-pling that allows sufficient relative movementbetween driving and driven members. The equip-ment must be positioned so the horizontal growthmoves into the coupling operating zone, not awayfrom it. Failure to do so results in excessivecrankshaft thrust bearing loading and/or couplingfailure. Sufficient clearance has been allowed if itis determined during a hot alignment check thatthe crankshaft still has end clearance. Location ofthrust bearings on 3500 Series Caterpillar Enginesis at the center of the crankshaft. It is at the rearof the crankshaft on other Caterpillar engines.

Cat Viscous Dampened Coupling

Caterpillar couplings use an internal gear designwith a rubber element between the gears. Siliconegrease aids in the dampening characteristics.

Clearances involved in internal gear design allowaccurate alignment measurement to be madewithout removing the rubber element, Figure 4.20.

The coupling for front-driven equipment is similarto the rear-drive coupling illustrated here. On frontdrives, the driven element, Figure 4.20, is sup-ported on the engine crankshaft as it does notweigh as much as the driving element.

Figure 4.20

Interpreting Dial Indicator Readings

With front crankshaft drives, indicator readingsmay appear to show the driven shaft is lower thanthe engine. This occurs because the dial indica-tor is mounted on the driven shaft instead of theengine, reversing the indicator reference point,Figure 4.21, due to the coupling configurations.

Figure 4.21

Alignment Procedures

Refer to the following Caterpillar Special Instruc-tion for more detailed information and spe-cific instructions on mounting and alignmentprocedures.

Final alignment should be performed after allmajor equipment has been installed on the base.Engines should be filled with oil and water andready to operate.

Misalignment between the diesel engine and allmechanically driven equipment must be kept toa minimum. Many crankshaft and bearing fail-ures can be traced to incorrect alignment of thedrive systems. Misalignment at operating tem-peratures and under load will always result invibration and/or stress loading.

Since there is no accurate and practical methodfor measuring alignment with the engine runningat operating temperature and under load, allCaterpillar alignment procedures must be per-formed with the engine stopped and the engineand all driven equipment at ambient temperature.

Place driven equipment in its final position asclosely as possible without taking indicator read-ings. There should be a minimum of 0.030 in.(0.76 mm) and a maximum of 0.125 in. (3.2 mm)of shims under each mounting surface of thedriven equipment.

Position driven equipment, using the leveling andalignment screws, Figure 4.22.

Figure 4.22

For cold alignment, the generator is mountedhigher than the engine to compensate for ther-mal growth, bearing clearances, and flywheeldroop, Figure 4.21.

Installation of Cat Viscous Dampened Coupling

When using the Caterpillar viscous dampenedcoupling, the rubber elements should be installedat this time. Install the coupling grease retainerplate. Install the silicone grease after couplingend clearance is correct.

Shift generator fore and aft as necessary to assurethe inner member of the coupling is properlypositioned between the rear retaining plate of thecoupling and engine flywheel to allow for hori-zontal growth. Failure to do so can result in exces-sive crankshaft thrust bearing loading and/orcoupling failure.

Using a flexible steel scale or depth gauge, meas-ure coupling end clearance to check that horizon-tal thermal growth will not cause metal-to-metalcontact within the coupling, Figure 4.23. Measuredistance (axial clearance dimension) from theouter face of inner coupling member to the outerface of grease retainer plate. The distance shouldbe 0.34 ± 0.03 in. (8.6 ± 0.8 mm) for front drivesand 0.41 ± 0.03 in. (10.4 ± 0.8 mm) for reardrives (flywheel-mounted couplings.)

Other Couplings

Flexible element of other couplings may need tobe removed during alignment checks. Elementstiffness can prevent accurate alignment readings.

With coupling element removed, driving anddriven members of the coupling should be rotatedtogether during alignment checks. This preventsface or bore runout of piece parts from affectingdial indicator readings. When both members arerotated together, only equipment misalignmentwill register on dial indicator readings.

Form No. TitleSEHS7654 Alignment — General InstructionsSEHS7259-06 Alignment of Single Bearing GeneratorsSEHS7073-01 Alignment of Two-Bearing Generators

53 LEBW1414-00

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Final Alignment

Use indicator support brackets to mount two dialindicators to simultaneously measure bore andface misalignment. See Figure 4.24 for properformat to record alignment readings.

Be sure crankshaft end thrust is always in thesame direction before taking a face reading. Zeroboth dial indicators at the top and take readingsevery 90 degrees (1.5 rad). Rotate the completeassembly by barring the engine over.

Figure 4.25 illustrates the method to be used,provides instructions to be followed and lists

alignment limits for various generator drivearrangements.

When the generator is moved to correct facealignment, it will be necessary to recheck borealignment and vice versa.

When the engine drives more than one genera-tor, recheck alignment of each generator after allgenerators have been aligned.

For instructions on installation of shims andmounting bolts on the engine, refer to the EngineMounting Section.

Figure 4.23

Figure 4.24

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After completion of the final shimming and bolt-ing operation, recheck coupling alignment.

Crankshaft end play should be checked after unitis up to operating temperature. It should bebetween 0.007 to 0.025 in. (0.178 to 0.635 mm).

Realignment LimitsRealignment is not required until field check lim-its are reached. When these limits are reached,units should be realigned to limits shown in pre-vious paragraphs.

Alignment of Close-CoupledDriven Equipment

Close-coupled components, such as single-bear-ing generators, close-coupled two-bearing gen-erators, transmissions, compounds, etc., rely onbolting together of two piloted housings to deter-mine alignment. When two piloted housings arejoined together in a parallel manner, they are inalignment. However, outside stresses can beintroduced by poor mounting practices and allowthe flywheel housing to flex. This can contributeto high vibration.

To check for outside stresses, loosen the mount-ing bolts between the driven equipment andengine flywheel housing. There should be no con-tact between flywheel housing and driven equip-ment housing at this time to assure neitherhousing is being stressed. Clearance between thetwo separated faces should be parallel within0.005 in. (0.13 mm). See Figure 4.26. Oilfieldgenerators are extra heavy and may distort theflywheel housing when it is not parallel to engine.

Figure 4.26

TWO BEARING ALIGNMENT — 21 INCH (534 mm) BASE AND BASE-WITHIN-A-BASE TYPE

Figure 4.25

To avoid this, make sure there is a minimum0.001 in. (0.03 mm) gap for the full 360 degreeswhen making this parallelism check.A dial indicator mounted between flywheel andgenerator rotor is sometimes used to check align-ment. However, after the generator housing ispiloted into and bolted to the flywheel housing,alignment is not checked by the dial indicatormethod.When the dial indicator method produces resultsin conflict with the parallelism check of the twohousings, Figure 4.26, such conflict indicates therear bearing of the driven equipment is not cen-tered in relation to the engine and is subject togenerator manufacturer’s accepted tolerances,flywheel housing nominal runout, and flywheeldroop.Generator mounting feet should not be shimmedafter the generator housing is bolted to the fly-wheel housing. Such practices stress both thegenerator housing and flywheel housing and cancause vibrations.It is not necessary to make this check on smallerCaterpillar Generator Sets where the engine doesnot have rear mounting feet but relies on the gen-erator supports, Figure 4.18. However, this checkis necessary on smaller Caterpillar Engines wherethe driven equipment is also rigidly connected toanother piece of equipment. A common exampleof this would be a mechanical drive where theclutch mechanism is bolted to the compound. Poormounting practices with this arrangement cancause excessive stresses in the flywheel housing.Single bearing generators are recommended tohave a pilot shaft extension and loose fitting flexplates or no pilot shaft extension but with pilotedplates. This aids in maintaining proper alignment.If vibration is noted at assembly of a generatorhaving coupling plates piloted into the flywheel,correction can often be made by repositioningcoupling plates 1⁄4 turn with respect to the origi-nal location. Start the unit and observe thechange in vibration. A second or third relocationmay be necessary to find the position of lowestvibration. Locate plates at point of lowest vibra-tion. This procedure allows manufacturing toler-ances to attempt to cancel each other.Before bolting coupling plates onto the flywheel,always rotate engine to the same position (i.e.,no. 1 TDC). Tighten half the bolts while the fly-wheel is in this position. Then rotate as necessary

to tighten other bolts. This procedure assures thatany sag in the crankshaft is always as the sameposition when the plates are fastened to flywheel.

Alignment of Mechanical DrivesImproper alignment will result in excessive vibra-tion, short life of compound bearings and clutchparts and a need for frequent realignment. Goodalignment practices include proper shimming,correct torque on hold-down bolts, and accuratedial indicator usage. See the section on GeneralAlignment Information for additional information.

Alignment Procedures

Final alignment should be performed after allmajor equipment has been installed on the base.Engines should be filled with oil and water andready to operate.

When clutches are used that contain air bladders,pay careful attention to air pressure; the allow-able amount of misalignment goes down as airpressure increases. Alignment limits must notexceed limits established for a Caterpillar viscousdampened coupling or for the clutch, whicheveris smaller.

Clutches are to be disengaged when alignment ischecked, Figure 4.27. Rotate clutch slowlythrough 360 degrees (6 rad) and check total indi-cator reading at 90 degree (1.5 rad) intervals.Shim engine, as required, to achieve correct align-ment, Figure 4.5.

ALIGNMENT CHECKFigure 4.27

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Dial indicator readings will include an error dueto runout of clutch or flywheel parts. Whereexcessive runout is suspected, check and cor-rect as required.

Non-Cat Bases

Bases not manufactured by Caterpillar mustmeet several design criteria. These bases must berigid enough to limit torsional and bending forcescaused by torque reaction and subbase flexing.They must prevent excessive bending forcesfrom passing to the engine block, couplings, anddriven unit during shipment. To prevent reso-nance, they must have a natural frequency out ofthe operating speed range. They must allow suf-ficient space for shimming so proper alignmentcan be accomplished.

VibrationAll mechanical systems with mass and elasticityare capable of vibration. Engines produce vibra-tion due to combustion forces, torque reactions,structural mass and stiffness combinations, andmanufacturing tolerances on rotating compo-nents. These forces may create conditions rang-ing from unwanted noise to high stress levels,and possible ultimate failure of engine or drivencomponents.The same amplitude and frequency of vibrationgenerated by the engine could result in structuraldamage if a fixed installation were housed in abuilding, or close to sensitive instruments or equip-ment, such as computers.Other influencing factors are foundation design,soil load characteristics, and other machineryoperating in close proximity.Vibrating stresses can reach destructive levels atengine speeds which cause resonance. Reso-nance occurs when natural system frequenciescoincide with engine excitation frequencies.Engine vibrations are produced and maintainedby regular, periodic driving forces set up byunbalanced moving masses. These are calledforced vibrations.Free vibrations have no driving force. When setin motion such vibrations, if undamped, wouldcontinue indefinitely with constant amplitude andnatural frequency.

If the frequency of a forced vibration is the sameas the natural frequency of free vibrations, exces-sive vibration results. This is called resonanceand can cause serious problems.

Mass Elastic System

Engine vibration may be of the following typesand causes:

1. Linear vibration — vertical and/or horizontalinertia forces due to lack of balance in recip-rocating or rotating machinery.

2. Torque reaction — not a vibratory force, butmay excite vibration.

3. Torsional vibration of shafting — occurs inany rotating mass elastic system (two ormore masses connected by an elastic shaft)where periodic forces are present. Wherethese forces recur near the natural frequencyof torsional vibration, resonance may developand cause dangerous stress.

4. Axial vibration of shafting — when torquesare applied to a crankshaft, it is alternatelyshortened and lengthened. This could betroublesome if the natural axial frequency isnear a torsional frequency.

Generator sets need no isolation for protectionfrom self-induced vibrations. However, isolationis required if:

1. Engine vibration must be separated frombuilding structures.

2. Vibrations from nearby equipment are trans-mitted to inoperative generator sets.

3. System is supported on a flexible mountingsurface, such as a trailer bed.

Vibration isolators prevent the transmission of pos-sible damaging generator set vibration through-out a building. Noise is also reduced.

When an engine and generator are to be assem-bled to each other, vibration studies and testsmust be completed to assure satisfactory, trou-ble-free operation on the job site. With factoryassembled generator sets, the responsibility isassumed by the manufacturer. In any case, wher-ever assembly takes place, someone mustassure the integrity of the installation from avibration standpoint.

Perfectly balanced rotating devices can vibrateif not properly aligned.

57 LEBW1414-00

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Vibration Measurement

Vibration measurements on large engine unitsshould be made using the Caterpillar VibrationAnalyzer, Part No. 4C-3030. If Caterpillar meas-uring equipment is not available, an equivalentdevice capable of measuring peak-to-peak dis-placement at selected frequencies, overall veloc-ity, and overall displacement should be used.

Vibration should be measured at nine points on atwo bearing generator set. Comparable points onnon-generator driven equipment may be impor-tant. These points are illustrated in Figure 4.28and are described below.

Point 1

Horizontal direction at the front of the engine;locate the probe on the left side of the block at thecrankshaft centerline.

Point 2

Vertical direction at the front of the engine; locatethe probe on the block top deck in the plane ofthe crankshaft centerline.

Point 3

Horizontal direction at the rear of the engine;locate the probe on the side of the block at thecrankshaft centerline.

Point 4

Vertical direction at the rear of the engine; locatethe probe on the block top deck (or rear housing)in the plane of the crankshaft centerline.

Point 5

Vertical direction at the generator front bearing;locate the probe on the bearing housing at theshaft centerline.

Point 6

Horizontal direction at the generator front bear-ing; locate the probe on the side of the bearinghousing at the shaft centerline.

Point 7

Vertical direction at the generator rear bearing;locate the probe on the bearing housing at theshaft centerline.

VIBRATION MEASURING POINTS

Figure 4.28

59 LEBW1414-00

Point 8

Horizontal direction at the generator rear bear-ing; locate the probe on the side of the bearinghousing at the shaft centerline.

Point 9

Axial direction at the generator rear; locate theprobe on the rear right outside edge of thegenerator structure (not sheet metal) at the shaftcenterline.

Vibration measurements must be made at theadvertised driven equipment rating (100% load).If additional data is desired, it is recommendedthat measurements be made at 0% load, 50%load, and 75% load. It may be useful to takevibration measurements also at plus and minus10% of rated speed, at no load.

Data must be reported in terms of peak-to-peakdisplacement (mils) at half order frequency, firstorder frequency, overall velocity level (in/s) andoverall displacement (mils) for each of the ninemeasuring locations. A chart can be used torecord and report the measured vibration data.

Vibration Limits

The vibration levels for any load condition, at anyof the nine measuring locations, must not exceedthe following guideline limits:

1. Peak-to-peak displacement at half order fre-quency = 5 mils (0.13 mm)

2. Peak-to-peak displacement at first order fre-quency = 5 mils (0.13 mm)

3. Overall displacement = 8.5 mils (0.22 mm)

4. Overall velocity = 1.35 in/s (34.3 mm/s)

This is applicable to both Diesel and Gas Engines(reference: EDS 73.1, Linear Vibration).

Consult the manufacturer of the driven equip-ment for applicable vibration limits.

If the measured vibration levels exceed the limits,contact your Caterpillar dealer representative orCaterpillar factory representative for assistance.

Warning: It is not an acceptable practice to lowerthe package vibration levels when operating atstable conditions by tightening the snubber boltson the Caterpillar vibration isolators. This prac-tice will only hide vibration problems.

Linear Vibration

Linear vibration is exhibited by noisy or shakingmachines, but its exact nature is difficult to definewithout instrumentation. Human senses are inad-equate to detect relationships between the mag-nitude of vibration and period of occurrence. Afirst order (1 2 rpm) vibration of 0.010 in.(0.254 mm) displacement may feel about thesame as third order measurement of 0.002 in.(0.051 mm).

Vibration occurs as a mass is deflected andreturned along the same plane and can be illus-trated as a single mass spring system (seeFigure 4.29). With no external force imposed onthe system, the weight remains at rest and thereis no vibration. But when the weight is moved ordisplaced and then released, vibration occurs.The weight travels up and down through its orig-inal position until frictional forces cause it to rest.When external forces, such as engine combus-tion, continue to affect the system while it vibrates,it is termed forced vibration.

MASS-SPRING SYSTEM

Figure 4.29

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Time required for the weight to complete onemovement is called a period (see Figure 4.30).

ILLUSTRATION OF A PERIOD

Figure 4.30

Maximum displacement from the mean positionis amplitude; interval in which the motion isrepeated is called the cycle.

If the weight needs one second to complete acycle, the vibration frequency is one cycle persecond.

If one minute, hour, day, etc., were required, itsfrequency would be one cycle per minute, hour,day, etc. A system completing its full motion20 times in one minute would have a frequencyof 20 cycles per minute, or 20 cpm.

Establishing vibration frequency is necessarywhen analyzing a problem. It allows identifica-tion of engine component or condition causingthe vibration.

Total distance traveled by the weight, from onepeak to the opposite peak, is peak-to-peakdisplacement. This measurement is usuallyexpressed in mils, one mil equaling one-thou-sandth of an inch [0.001 in. (0.025 mm)]. It is aguide to vibration severity.

Average and root-mean-square (rms) are used tomeasure vibration (rms = 0.707 times the peakof vibration). These terms are referred to in the-oretical discussions.

Another method to analyze vibration is measur-ing mass velocity. Note that the example is notonly moving but changing direction. The speed ofthe weight is also constantly changing. At its limit,the speed is “0”. Its speed or velocity is greatestwhile passing through the neutral position.

Velocity is extremely important; but because ofits changing nature, a single point has been cho-sen for measurement. This is peak velocity nor-mally expressed in inches per second.

Velocity is a direct measure of vibration and pro-vides best overall indicator of machinery condi-tion. It does not, however, reflect the effect ofvibration on brittle material.

Relationship between peak velocity and peak-to-peak displacement is compared by:V Peak = 52.3 2 D 2 F 2 106

Where:V Peak = Vibration velocity in inches per second

peak.

D = Peak-to-peak displacement, in mils(1 mil – 0.001 in.).

F = Frequency in cycles-per-minute (cpm).

Acceleration is another characteristic of vibra-tion. It is the rate of velocity change. In the exam-ple, note that peak acceleration is at the extremelimit of travel where velocity is “0”. As velocityincreases, acceleration decreases until it reaches“0” at the neutral point.

Acceleration is dimensioned in units of “g”(peak), where “g” equals the force of gravity(980 2 6650 mm/s2 = 386 in./s2 = 32.3 ft./s2).

Acceleration measurements, or “g’s”, are usedwhere relatively large forces are encountered. Atvery high frequencies (60,000 cpm), it is per-haps the best indicator of vibration.

Vibration acceleration is calculable from peakdisplacement :g Peak = 1.42 2 D 2 F2 2 108

Machinery vibration is complex and consists ofmany frequencies. Displacement, velocity, andacceleration are all used to diagnose particularproblems. Displacement measurements arebetter indicators of dynamic stresses and are,therefore, commonly used. Note that overall, ortotal peak-to-peak displacement, described inFigure 4.31, is approximately the sum of indi-vidual vibrations.

61 LEBW1414-00

PEAK-TO-PEAK DISPLACEMENT

Figure 4.31

IsolationGenerator sets need no isolation for protectionfrom self-induced vibrations. They easily with-stand any vibrations which they create.

However, isolation is required if engine vibrationmust be separated from building structures, or ifvibrations from nearby equipment are transmit-ted to inoperative generator sets. Caterpillar Gen-erator Sets with isolation mounts between thegenerator set and base already satisfy theserequirements. Running units are rarely affectedby exterior vibrations. Methods of isolation are thesame for external- or self-generated vibrations.

Isolation Location

Several commercial isolators provide variousdegrees of isolation. Generally, the lower the nat-ural frequency of the isolator, the greater thedeflection (soft) and more effective the isolation.Weight of generator sets can be unequally dis-tributed among the isolators, within the limits ofthe isolators. However, isolator overloading willeliminate isolator benefits. Isolators are mosteffective when located under generator mount-ing and engine front support (see Figure 4.32).If additional support is desired, place an isolatormidway between front and rear mounts andunder radiator.

REFERENCES FOR DISTANCES

Figure 4.32

To apply isolators, wet weight and center of grav-ity of the assembled unit must be established.Assuming engine and generator are assembledto a base, wet weight (WT) and assembled centerof gravity can be calculated. A common referenceis needed (see Figure 4.32). In this case, use therear face of the flywheel housing or engine block.Because measurements are to both sides ofthe reference, one direction can be considerednegative.

WT (D) = WE (D2) – WG (D1) + WR (D3)

D = WE (D2) – WG (D1) + WR (D3)___________________________WT

WT = wet weightWE = engine weightWG = generator weightWR = radiator weightD1,2,3 = distances

If additional equipment is added, the process isrepeated to determine a new center of gravity.

Having established center of gravity for the totalunit (see Figure 4.33), loading on each pair ofisolators is determined by:

S1 = WT S2 = WTA__C

B__C

LEBW1414-00 62

DETERMINATION OF ISOLATOR LOCATION

Figure 4.33

Isolators are sized to have natural frequencies farremoved from engine exciting frequencies. Ifthese frequencies were similar, the entire unitwould resonate. The transmissibility chart inFigure 4.34 depicts this condition. It also showsthe significant improvement caused by decreas-ing the mounting natural frequency to allow aratio increase above √ , or 1.414.

Isolation Methods

Vibration is reduced by commercially availablefabricated isolators or bulk isolators. Both tech-niques utilize static deflection, with increaseddeflection resulting in greater isolation. Althoughinternal damping of various materials cause per-formance differences, the vibration chart inFigure 4.35 describes the general effect deflec-tion has on isolation. By using engine rpm as thenominal vibration frequency, magnitude of com-pression on isolating materials can be estimated.

The unit can be separated from supporting sur-faces by these soft commercial devices, i.e., thosewhich deflect under the static weight. Mountingrails or fabricated bases withstand torque reac-tions without uniform support from the isolators.

2

TRANSMISSIBILITY CHART

Figure 4.34

63 LEBW1414-00

BASIC VIBRATION CHART

Figure 4.35

Piping connected to generator sets requires iso-lation, particularly when generator sets mount onspring isolators. Fuel and water lines, exhaustpipes, and conduit could otherwise transmitvibrations long distances. Isolator pipe hangers,if used, should have springs to attenuate low fre-quencies, and rubber or cork to minimize highfrequency transmissions. To prevent buildup ofresonant pipe vibrations, support long piping runsat unequal distances (see Figure 4.36).

PIPE RUNS SUPPORT

Figure 4.36

Rubber

Rubber isolators are adequate for applicationswhere vibration control is not severe. By carefulselection, isolation of 90% is possible. They iso-late noise created by transmission of vibratoryforces. Avoid using rubber isolators with naturalfrequencies near engine excitation frequencies.

Adding rubber plates beneath spring isolatorsblock high frequency vibrations transmittedthrough the spring. These vibrations are notharmful but cause annoying noise.

Spring

The most effective isolators are of steel springdesign. They isolate over 96% of all vibrations andnoise transmitted from rotating machinery tothe foundation or mounting surface. Conversely,isolators can absorb disturbances generated byadjacent machinery and prevent damage frombeing transmitted to idle equipment.

Spring-type linear vibration isolators are includedin offshore power modules. These isolators per-mit mounting the generator set on a surfacecapable of supporting only the static load.

A detail of a spring-type isolator shows theaddition of thrust blocks to restrict lateral move-ment without interfering with the spring function(see Figure 4.37). Limit stops are also included,for tilt angle requirements.

VIBRATION ISOLATOR

Figure 4.37

LEBW1414-00 64

No allowance for torque or vibratory loads isrequired. As with direct mountings, no anchorbolting is usually required. However, when oper-ating in parallel, vertical restraints are recom-mended and the isolator firmly fastened to thefoundation. Spring isolators are available withsnubber for use when engines are side loaded orlocated on moving surfaces.

Other Isolation Methods

Fiberglass, felt, composition, and flat rubber dolittle to isolate major vibration forces. Thesematerials tend to compress with age and becomeineffective. Because deflection of these types ofisolators is small, their natural frequency is rela-tively high compared to the engines. Attemptingto stack these isolators or apply them indiscrim-inately could force the system into resonance.

Land rig power module include composition padsat the three internal mounting points. Land rigmodules have reduced concern over vibrationtransmission. Composition pads are easilydesigned to remain in place during the frequentrig moves.

If no isolation is required, auxiliary generator setsmay rest directly on the mounting surface.Factory assembled units are dynamically bal-anced and theoretically there is no dynamic load.Practically, the surface must support 25% morethan the static weight of the unit to withstandtorque and vibratory loads. Unless the engine isdriving equipment which impose side loads, noanchor bolting is required. This normally appliesto all non-parallel generator set mountings. Thinrubber or composition pads minimize the unit’stendency to creep or fret foundation surfaces.

External Isolation

Piping connected to generator sets requires iso-lation, particularly when generator sets aremounted on spring isolators. Fuel and water lines,exhaust pipes, and conduit could otherwise trans-mit vibrations long distances.

If isolator pipe hangers are used they should havesprings to attenuate low frequencies, and rubberor cork to minimize high frequency transmissions.

To prevent buildup or resonant pipe vibrations,long support piping should run at unequal dis-tances (see Figure 4.36).

Vibration carried throughout an enclosure causesearly failure of auxiliary equipment. Relays,switches, gauges, and piping are adverselyaffected.

Noise, while normally only annoying, can attainlevels objectionable to owners and operators. Ifoperating near property lines, noise could exceedlocal ordinances.

Torsional Vibration

Torsional vibrations occur as subjects, such asan engine crankshaft, twist and recover. Standardgenerator set components withstand normalstresses caused by combustion forces and torquereactions. A generator set must prevent thenatural frequency of the drive train from approach-ing the unit’s operating speed. Failure of crank-shaft, couplings, gears or bearings may resultwithout this attention.

Torsional vibrations originate with the piston powerstroke. The simplified drive train in Figure 4.38illustrates relationship of shaft diameter, length,and inertia on the natural system frequency.

TORSIONAL VIBRATIONS

Figure 4.38

Even though generator sets, factory packagedon Caterpillar designed bases, avoid criticalspeeds where resonant conditions occur, allapplications, whether packaged by Caterpillar orothers, require a torsional vibration analysis. Thisassures compatibility of the engine and drivenequipment. It must be performed by either thecustomer or by Caterpillar, depending on the cus-tomer’s preference. Customer performed analy-ses are subject to Caterpillar review and approvaland Caterpillar does not assume responsibilityfor analysis performed by others without specificCaterpillar review and approval. Without the

65 LEBW1414-00

approval, no warranty for vibration caused prob-lems can be claimed from Caterpillar. ForCaterpillar-performed analyses, a complete setof technical data (see below) must be submittedto Caterpillar before calculations are undertaken.The report will include a mathematical determi-nation of the natural frequency, critical speeds,relative amplitudes of angular displacement, andapproximate nodal locations of the completeelastic system (both engine and driven equip-ment). See the Special Additions section of theprice list for ordering information.

NOTE: Consult factory on compound installa-tions. There may be additional charges for analy-ses of applications where more than one enginedrives a single load. A separate torsional analy-sis is also required for each engine with differentdriven equipment in multiple engine installations.

Technical data required:

1. The operating speed range.

2. Load demand curve on generator sets whichhave a load dependent variable rigiditycoupling.

3. General arrangement drawing or sketch ofcomplete system, including data on equip-ment driven from front of engine.

4. With driven equipment on both ends of theengine, the power demand of each end isrequired. In addition, simultaneous frontand rear power (maximum engine load) isrequired.

5. Make, model, WR2 (rotational inertia), and tor-sional rigidity on all couplings used betweenthe engine and driven equipment.

6. WR2 of each rotating mass. Weight of eachreciprocating mass.

7. Torsional rigidity and minimum shaft diam-eter or detailed dimensions of all shaftingin the driven system whether separatelymounted or installed in a housing.

8. The ratio of the speed reducer or increaser.The WR2 and rigidity submitted for a speedreducer or increaser should state whether ornot they have been adjusted to engine speed.

9. For reciprocating compressor applications,a harmonic analysis of the compressortorque curve under various load conditions.If not available, a torque curve of the com-pressor under each load condition throughone compressor cycle. The WR2 of all avail-able flywheels for the compressor.

Couplings

A coupling must be torsionally compatible withengine and driven load so that torsional vibrationamplitudes are kept within acceptable limits. Amathematical study called a torsional vibrationanalysis should be done on any combination ofengine-driveline-load for which successful expe-rience doesn’t already exist. A coupling with thewrong torsional stiffness can cause serious dam-age to engine or driven equipment.

All couplings have certain operating ranges ofmisalignment, and the manufacturers should becontacted for this information.

Some drives, such as U-joint couplings, have dif-ferent operating angle limits for different speeds.

As a general rule, the angle should be the sameon each end of the shaft (see Figure 4.39). Theyokes must be properly aligned and sliding splineconnections should move freely. If there is noangle at all, the bearings will brinell due to lackof movement.

Cyclic Irregularity

Cyclic irregularity is a nondimensional ratiodescribing degree of crankshaft twist occurringbetween two successive firings of cylinders dur-ing steady-state operation. Formulas to repre-sent this movement were derived before moderninstrumentation allowed measurement. The ratiois expressed as:

Cyclic irregularity: rpm rpm(maximum) – (minimum)________________________

rpm (average)

System speed varies with connected rotatingmass. Cyclic irregularity differs, therefore, for abasic engine, one driving a generator, or addi-tional equipment.

This ratio compares merits of large slow speedengines which were custom made, but has littlevalue applied to modern medium speed engines.

LEBW1414-00 66

Out-of-Balance Driven Equipment

The engine itself is designed and built to run verysmoothly. Objectionable vibration generallyarises from either poor driveline componentmatch to the engine or unbalance of the drivenequipment. Reciprocating equipment with largeimbalances, for example, can cause prematurefailure of the mounting structure or undesirablevibration even though the unit is properly mounted,aligned, and isolated from the engine.

Even though the engine and the driven load arein balance, it is also possible to encounter unde-sirable and damaging vibration as a result of thedriving or connecting equipment having a mis-alignment or out-of-balance condition. Longshafts, drives, gear assemblies, clutches, or anytype of coupling where misalignment, out-of-bal-ance, or mass shifting may occur, are probablesources of vibration.

Alignment

An unsatisfactory engine mounting nearly alwaysresults in alignment problems between the engineand the driven machinery. Assuming that failureof the driven equipment does not occur first, theforces or loads transmitted to the engine in theform of pounding, twisting, flexing, or thrust couldresult in engine crankshaft and bearing failure.Costly failures of this nature can be avoided if, atthe design and installation stage, the importanceof proper alignment between the engine anddriven load and adequate mounting to maintainalignment is considered.

If this is possible, a suitable flexible coupling mustbe incorporated into the drive train to compen-sate for misalignment.

Good alignment practices include proper shim-ming, correct torque on hold-down bolts, accu-rate dial indicator usage, allowances for bearingclearances, thermal growth, and accounting forother characteristics of the engine.

UNIVERSAL JOINT SHAFT DRIVE

Figure 4.39

67 LEBW1414-00

DefinitionsNoise can be defined as all unwanted sounds.Music is sound and can be pleasant to somepeople and noise to others. Noise and sound areoften used to describe the same physical char-acteristics. Noise is generally random in naturewithout distinct frequency components. Noisecan produce undesirable psychological effectson people and physical damage to the ears.Noise can be annoying and affect verbal com-munications at work and away. At times, it mayimpact behavior, including short term and longterm hearing loss, muscle tension, respiratoryreflexes, stress level, heart function, etc. Recog-nizing this, many governmental agencies aroundthe world have established regulatory limits forvarious levels of noise.

The noise from the engine comes mainly fromcombustion, mechanical forces and from theexhaust and air intake sources.

Frequency of sound refers to the rapidity orcycles of an oscillation in a unit time. The con-ventional unit is Hertz (Hz) — one Hz being onecycle per second.

Sound Waves and MeasurementAs sound waves radiate, their strength diminishes(see Figure 5.1). As distance traveled doubles,the wave amplitude is reduced by one-half. Thisrule applies if the first measuring point is at leasttwo or three times the largest dimension of thenoise source, usually about three feet.

Figure 5.1. Distance vs. wave amplitude.

Sound waves impinging on a microphone pro-duce voltages proportional to sound pressures.The signals measure amplitude or strength, ofthe sound pressure waves. Amplitude and fre-quency are the only sound properties measura-ble using ordinary techniques.

Sound Pressure

The extensive audible range of sound compli-cates noise ratings. The human ear hears pres-sure levels that are about 100,000 times strongerthan the lowest pressure it is affected by. For thisreason, measuring instruments have extraordi-nary range and are scaled in decibels (dB). Thedecibel scale is logarithmic, which allows thewide range of sound pressures to be measured inonly two- or three-digit numbers.

Sound Pressure Level (SPL) in dB =

20 log10 2

The reference pressure is taken as: 20 µPa or2 2 10–4 microbars = 0 dB. The relationshipbetween µPa and dB is that when multiplying thesound pressure (µPa) by 10, 20 dB is added tothe dB level. Decibel (dB), is the relative meas-urement of amplitude of sound. Sound is a pres-sure which makes the membrane in the humanear deflect. The softest pressure the human earcan hear is 20 µPa (1 atmospheric pressure =1 bar = 100 kPa = 14.5 psi) but the ear can takepressures up to more than 1 million times higher.

Frequency — Weighting Networks

The ear is more sensitive to high frequencies thanlow frequencies. To approximate the effect ofsound on the average person, measurements areweighted according to frequencies correspon-ding to the sensitivity of the ear. Loudness canbe measured by filtering the microphone signalto reduce the strength of the low frequency sig-nals and give more weight to frequencies in the5,000–10,000 Hz range. The signal from themeasuring microphone is fed to an amplifier, thento an attenuator, which is calibrated in decibels.The signal is then fed to one of four weightingnetworks, referred to as A, B, C, and D. Theresponse of the network chosen modifies theinput signal accordingly.

The most commonly used network is weightingA (A-scale), and it is known as dBA or dB(A).

Measured pressure___________________Reference pressure

Distance Sound StrengthX 100%2X 50%4X 25%

NOISE

Figure 5.2 shows the response characteristics foran “A” filter. The result of adjustments through-out the frequency range is a total decibel ratingwith a correction for various frequencies toapproximate the human ear’s sensitivity.

RESPONSE CHARACTERISTICS OF “A” FILTER

Figure 5.2

Octave Band Levels

More detail is required of the frequency dis-tribution of a noise than provided by an A-weighted measurement. Measurementsare made with filters subdividing sounds over theentire audible range into standardized frequencybands, permitting the pressure levels of only thesound within each subdivision to be measured.Each filter spans an octave; that is, the upper fre-quency limit is twice the lower limit as shown inFigure 5.3. Sound levels in each octave are meas-ured in decibels and are referred to as octaveband levels.

STANDARD OCTAVE BANDS (ANSI STANDARD S1.11 IEC 225)

Figure 5.3

Loudness

The human ear does not use sound pressuredecibels to judge loudness. Rating noise loud-ness is a complex operation because humanhearing is also frequency sensitive.

Sounds with frequencies in the 5,000-10,000 Hzrange are the easiest to hear; sounds with verylow frequencies are the hardest. Hearing lossfrom exposure to noise is frequency sensitive.

Direction of Sound

Sound is mostly directional, meaning that thesound tends to move more in one directionthan another.

The contour of the sound wave can be complex.By measuring the sound pressure level threedimensionally around the engine, the contour canbe determined (see Figure 5.4).

It is not only the source of the sound which willgive the direction, but also any kind of reflectivesurface in the area of the engine, i.e. floor, wallsor ceiling.

BandDesignation(CenterFrequency)

BandLimits

8000 Hz

4000

2000

1000

500

250

125

63 Hz44 Hz

88

176

353

707

1415

2830

5650

11300 Hz

Signals enteringfilter

Lowfrequencies

Highfrequencies

Signals leavingfilter

dB totaldB(A) total

Frequency Hz

RelativeResponsedB

“A” weightedfiltering

- 5 0

+ 5

-10-15-20-25-30-35-40-45-50

20 50 100 200 500 1000 2000 5000 10,000

A

A

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69 LEBW1414-00

CONTOUR OF A SOUND WAVE

Figure 5.4

Noise Addition

When standing by an engine, the noise heardfrom other engines operating in the same areawill depend on the spacing of the engines andwhere the person is in relation to the spacing.

A chart showing the combined effect of up to tenequal sound sources is shown in Figure 5.5.

ADDITION OF EQUAL SOUNDS

Figure 5.5

Figure 5.6 shows the versatility of the decibel sys-tem. Although calculations are made on the basisof sound power, the system uses measured orcalculated sound pressures. Use the differencein the pressure levels of two sounds to find howtheir combined level exceeds the higher of thetwo. First adjust the levels for the distances fromthe source to the spot where the noises are beingadded. To add a third level, use the same processto combine it with the total of the first two.

ADDITION OF UNEQUAL SOUNDS

Figure 5.6

Sound Level Conversions

Sound level information is presented both interms of sound power level, SWL, dB(A), andsound pressure level, SPL, dB(A). SWL is the totalsound power being radiated from a source, andits magnitude is independent of the distance fromthe source. Relative loudness comparison betweenengines is simply a comparison of their soundpower levels at equivalent operating conditions.

When the sound power level (SWL) is known, thesound pressure level (SPL) at any distance froma point source (such as exhaust noise) can becalculated.

0

.5

1

1.5

2

2.5

3

0 2 4 6 8 10 12 14De

cib

els

ad

de

d t

o h

igh

er

of

two

no

ise

s to

ob

tain

to

tal i

n d

BDifference between two noises in dB

03 4 5 6 7 8 9 10

2

4

6

8

10

2

Increase in sound pressure dB or dB(A)

Incr

ea

se in

dB

or

dB

(A)

Number of sources

Engine

The equation for determining the sound pressurelevel of exhaust noise without any correction forambient temperature and pressure, is:Sound Pressure Level, SPL dB(A) =Sound Power Level, SWL dB(A) – 10 2 Log10 (CπD2)

Where C = 2 For exhaust source adjacent to aflat surface, such as a horizontalexhaust pipe adjacent to a flat roof.

or C = 4 For exhaust source some distancefrom surrounding surfaces, such asa vertical exhaust stack some dis-tance above roof.

D = Distance from exhaust noisesource (m).

For C = 4 = SPL = SWL - 20 Log10 D - 10.99

SPL measurement requires only a simple soundlevel meter. However, the sum of sound wavesarriving from every direction depends on theacoustic characteristics of the environment andvaries with position relative to the noise source.SPL cannot be used to describe the strength of anoise source without specifying relative positionand room acoustic properties of the test envi-ronment. A disadvantage is that sound pressurelevel conversion is valid for a point source only.It cannot be used for mechanical noise since thesource (overall engine) is quite large.

If the sound pressure level of a point source atsome distance is known, the sound pressurelevel at another distance can be calculated usingthis formula:

SPL2 = SPL1 – 20 2 Log10 (D2 ÷ D1)

Where: SPL1 = known sound pressure level,dB(A)

SPL2 = desired sound pressure level,dB(A)

D1 = known distance, ft. (m)

D2 = desired distance, ft. (m)

Noise ExposureAs mentioned before, exposure to excessivenoise causes permanent hearing damage andadversely affects working efficiency and com-fort. Recognizing this, the U.S. Government cre-ated the Occupational Safety and Health Act(OSHA) which established limits for industrialenvironments.

When an individual’s daily noise exposure, des-ignated D(8), is composed of two or more peri-ods of noise at different levels, the combinedeffect is calculated by: D(8) = (C1/T1) + (C2/T2)+ ... + (Cn/Tn). Where Cn is duration of expo-sure at a specified sound level and Tn is total timeof exposure permitted at a specified sound level(see Figure 5.7). The noise exposure is accept-able when D(8) is equal to or less than 1.

PERMISSIBLE NOISE EXPOSURES

Figure 5.7

Duration of AllowableDaily Exposure Level

(hours) dB(A)8 906 924 953 972 100

1.5 1021 105

0.5 1100.25 115

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71 LEBW1414-00

Engine packages include an engine and somepiece of driven equipment, such as a generatoror a compressor. Guidelines for installation designare provided, along with information on usingnoise data on Caterpillar units from TMI.

Some installations require very little noise abate-ment (for example, a remote facility far from peo-ple). Very sensitive installations, on the otherhand, may require extensive noise abatementmeasures. Because of the variety of noise crite-ria that may apply to a given site, it is impossi-ble to provide a description of abatementmeasures meeting all site criteria. It is the respon-sibility of the facility designer to ensure that thespecific criteria of the site are met.

It is strongly advised that a noise control expertbe involved in the facility design process fromthe beginning if the engine unit is to be installed

in a building or area that is noise sensitive. Sinceinternal combustion engines produce high noiselevels at low frequencies, many traditional noisecontrol approaches are relatively ineffective.Every aspect of facility design must thereforebe reviewed with special emphasis on low-fre-quency attenuation characteristics in order tomeet site criteria.

A typical approach to designing an engine instal-lation is as follows:

• Recognize the special requirements of engineinstallations. The first step is to becomeaware of the special noise characteristics ofengine installations. Possible sources, paths,and receivers of large-engine noise arereviewed.

ENGINE INSTALLATIONS

TMI contains the specific noise values (SPL) forthe specific engine at different ratings. Variousdefinitions are used and most can be found under“HELP” in TMI.

Free Field

Free field means that it is a 100% open area with-out any kind of sound reflections or other modi-fying factors.

Sound Pressure Level, SPL, —Mechanical or Exhaust

Sound pressure level is presented under twoindex headings: mechanical or exhaust.

Over one thousand data points per engine areused to prepare this data. There are eight octavebands and one overall reading taken at fourengine speeds, four loads, three distances, andfour positions around the engine.

Mechanical

Sound pressure level data is obtained by oper-ating the engine in an open “free” field andrecording sound pressure levels at a given dis-tance. The data is recorded with the exhaustsound source isolated.

Exhaust

Sound pressure level data is recorded with themechanical sound source isolated.

Measurements

The instrumentation used are Larsen/Davis andHewlett-Packard. All measurements are for “with-out” radiator fan arrangements.

Tolerances for the overall and for the octave banddata is shown below:

Overall Plus or minus 2 dB(A)60 Hz Plus or minus 5 dB(A)

125 Hz Plus or minus 5 dB(A)250 Hz Plus or minus 4 dB(A)500 Hz Plus or minus 3 dB(A)

1000 Hz Plus or minus 2 dB(A)2000 Hz Plus or minus 2 dB(A)4000 Hz Plus or minus 2 dB(A)8000 Hz Plus or minus 2 dB(A)

The confidence level of the above data is 99.73%,which means that only 27 out of each 10,000engines measured of the same configuration aslisted could fall outside of the nominal values plusthe tolerances shown for the same engine, therepeatability tolerance is ±1 dB(A).

TMI DATA

LEBW1414-00 72

Noise can be either airborne or structure-bornetransmitted. Airborne noise is transmitted throughair. Structure-borne noise is vibration transmit-ted through a structure; typically supporting theengine. Noise control methods are different forthe two sources. Noise control refers to appro-priate technology used for noise attenuation toacceptable levels.

Noise criteria at various frequencies for typicalareas are shown in Figure 5.8.

Airborne Noise ControlAirborne noise control is a straightforward andwell-developed area compared with structure-borne noise control. There is abundant infor-mation available on sound absorption andtransmission properties of common constructionmaterials, and there are accepted and provenprocedures for applying that information.

However, it is important to recognize that muchof the conventional information and procedureswere developed for higher-frequency noise, andthus may not be appropriate for engine units,which produce strong low-frequency acousticenergy. For example, structural and acousticresonances (conditions of minimum dynamic

stiffness) may coincide with pure-tone frequencycomponents of the engine noise, resulting in veryefficient transfer of energy. Conventional build-ing acoustics generally is based on statisticaldescriptions of noise, and therefore does notaddress resonance effects.

For some installations, airborne noise must becontrolled at several receiver points: inside theengine room; in other rooms in the building; andoutside the building. The simplest way to reduceairborne noise within a building is through goodbuilding layout. Equipment rooms should be sit-uated far from sensitive receiver locations in thebuilding. This takes advantage of the fact thatpropagating sound energy diminishes with dis-tance from the source. In addition, there are twoother methods of controlling airborne noise: withhigh transmission loss walls and with absorption.

It is helpful to review some terminology beforediscussing the sound transmission characteris-tics of walls. The transmission loss (TL) of a par-tition is a measure of the ratio of energy incidenton the wall to that transmitted through the wall,expressed in dB. The less relative sound trans-mitted through the wall, the higher the TL of thewall. TL is a function of frequency.

NOISE CONTROL

NOISE CRITERIA

Figure 5.8

Octave Bands in Cycles Per Second 31.5 63 125 250 500 1000 2000 4000 8000Highly Critical Hospital or

Residential Zone 71 63 44 37 35 34 33 33 33Night, Residential 73 69 52 44 39 38 38 38 38Day, Residential 76 71 59 50 44 43 43 43 43Commercial 81 75 65 58 54 50 47 44 43Industrial-Commercial 81 77 71 64 60 58 56 55 54Industrial 87 85 81 75 71 70 68 66 66Ear Damage Risk 112 108 100 95 94 94 94 94 94

• Identify site noise criteria. For example, is theinstallation in a remote or a populated area?Is it within a building sensitive to noise (forexample, a laboratory or a hospital)? Whatregulations, standards, or restrictions applyto noise? The noise criteria form an essen-tial part of the design goals. Since criteriavary from site to site, all the criteria that apply

to a particular site cannot be identified. How-ever, some guidelines for site noise criteriaare provided.

• Identify and select appropriate noise abate-ment measures. Guidelines for attenuation ofnoise, both through commercially availableequipment and through facility construction,are provided.

73 LEBW1414-00

The sound transmission class (STC) of a partitionis a single-number rating calculated from the par-tition TL. A reference contour is adjusted againstthe measured TL data, and the STC rating equalsthe value of the adjusted contour at 500 Hz. TheSTC rating does not include information in fre-quency bands below 125 Hz. This rating is use-ful for designing walls that provide insulationagainst the sounds of speech and music; it isinappropriate for industrial machinery with low-frequency energy such as engine units. TL datashould be used instead, whenever possible.In typical partitions, sounds at higher frequen-cies are attenuated more than sounds at lowerfrequencies. The highest transmission loss val-ues are found in cavity wall (two-leaf) construc-tions, where the two separate wall layers are wellisolated. The transmission loss values increasewith the masses of the individual leafs, the depthof the airspace, and the characteristics of anysound-absorptive material in the airspace.It should be noted that noise leaks can severelydegrade the performance of a partition. Materialsare tested for their transmission loss character-istics in a controlled laboratory setting, with alledges sealed. But in typical construction, soundleaks may occur at the edges of the wall, at open-ings for pipes or electrical outlets, and acrossshared ceilings (so-called flanking paths). A wallwith a leakage area equal to 0.01% of that of thewall area cannot exceed STC = 40, no matterhow high the STC of the wall construction.A partition may include elements with varioustransmission loss characteristics, for example,windows and doors. The transmission loss of thepartition must be calculated taking all elementsinto consideration.To estimate the total airborne noise transmissionloss of a facility, subtract the noise value for eachreceiver from the estimated room-average soundpressure level. If there is more than one space,the sum of the individual contributions must notexceed the criterion.

Mechanical Noise

Many techniques for isolating generator set vibra-tions are applicable to mechanical noise isolation.Modest noise reductions result from attention tonoise sources, i.e., reducing fan speeds, coatingcasting areas, and ducting air flows. But for atten-uation over 10 dB(A), units must be totally iso-lated. One effective method utilizes concrete

blocks filled with sand to house the generator set.In addition, the unit must incorporate vibration iso-lation techniques. A rough guide comparing var-ious isolation methods is illustrated in Figure 5.9.

Completely enclosed engines are impractical dueto openings required for pipes, ducts, and venti-lation. Enclosures with numerous openings rarelyattain over 20 dB(A) attenuation.

ILLUSTRATION OF ISOLATION METHODS

Figure 5.9

Intake Noise

Intake noise attenuation is achieved througheither air cleaner elements or intake silencers.Noise attenuation due to various air cleaners andsilencers can be supplied by the componentmanufacturer.

Originalmachine

Vibrationisolators

Baffle

Absorptionmaterialonly

Rigidsealedenclosure

Enclosure,andisolators

Enclosure,absorptionandisolators

Doublewalledenclosure,absorptionand isolators

Approximate sound levelreduction

dB(A)

0

2

5

5

15-20

25-30

35-40

60-80

LEBW1414-00 74

Exhaust Noise

Exhaust noise is typically airborne. Exhaust noiseattenuation is commonly achieved with a silencertypically capable of reducing exhaust noise15 dB(A) when measured 10 ft. (3.3 m) perpen-dicular to the exhaust outlet. Locating it near theengine minimizes transmission of sound to theexhaust piping. Since the number of cylindersand engine speeds result in varied exhaust fre-quencies, specific effects of mufflers must be pre-dicted by the muffler manufacturer.

Silencers/Mufflers

Silencers are used to attenuate airborne noise inpiping and duct systems. Their effectiveness gen-erally is frequency sensitive, so it is essential thatthey be matched to the frequency content of thenoise. There are two major categories of silencers;dissipative and reactive. Dissipative silencers useabsorptive, fibrous material to dissipate energyas heat. They are effective only for high fre-quency applications (i.e., 500 to 8000 Hz).

Reactive silencers, on the other hand, use achange in cross-sectional area to reflect noiseback to the source. They are typically usedfor low-frequency applications (such as internalcombustion engines), and they may incorporateperforated tubes to increase broadband per-formance. The effectiveness of a reactive silencerdepends on its diameter, volume, and overalldesign. Multi-chamber silencers provide maximumsound attenuation with some flow restriction.Straight-through silencers offer negligible flowrestriction with slightly lower sound attenuation.

Stack silencers are designed to be inserted directlyinto a stack and withstand a harsh environment.Finally, some manufacturers offer combinationheat-recovery silencers for hot gas exhaust.

Most manufacturers offer silencer dynamicinsertion loss (DIL) information in octave bandsfrom 63 to 8000 Hz, tested in accordance withASTM E-477. DIL is the difference in sound levelwith and without a silencer installed in pipe orduct with air flow. Some manufacturers ratesilencers as being “industrial”, “commercial”, or“residential” grade; in such a case, the DIL ofthe silencer should still be requested in order todetermine the grade of silencer most suitable forthe installation.

To determine the DIL required by a particularapplication, information is required on the actual(unsilenced) and desired noise levels at the emis-sion point. The difference between these valuesis the silencer DIL. The desired source level isdetermined from the criteria governing the site.

When used to attenuate exhaust noise, thesilencer must be sized to accommodate the spec-ified volume of flow without imposing excessivebackpressure. The flow area for a given back-pressure can be calculated from the engineexhaust flow (CFM) and the exhaust tem-perature. The pressure drop will determine therequired size of the silencer.

Sound Absorption Treatments

Acoustically absorptive surfaces convert acousticenergy into heat and are generally described bysound absorption coefficients in octave bands.Absorptive surfaces may be used to reduce thereverberant (reflected) sound field within a room.As mentioned above, reducing the reverberantfield within a room can also reduce the noisefield outside the room. It should be noted thatabsorptive materials do not attenuate the directsound field.

The absorption of a room may be estimated onan octave-band basis from the absorption coef-ficients and the area of each room surface (ceil-ing, walls, and floor). Alternatively, the roomabsorption may be determined through rever-beration time measurements. Using this infor-mation and the source sound power data, thenoise reduction that can be obtained by addingabsorption to a room may be determined.Information on the absorption coefficients of amaterial or element may be obtained from themanufacturer.

A wide variety of commercially available soundabsorbing elements are available for almost everyapplication. Ceiling treatments include lay-in tilesor boards (for suspended ceilings), tiles that canbe directly affixed to the ceiling surface, andsuspended absorbers. Acoustic wall panels rangefrom “architectural” panels with attractive finishesto perforated metal panels filled with absorbingmaterials. Concrete blocks with slotted faces andacoustical fill may be used to add sound absorp-tion to normal concrete block wall construction.

75 LEBW1414-00

Sound absorbing elements are selected onthe basis of their sound absorption coefficient inthe octave bands of interest. In addition, the ele-ments must survive their environment, be easy tomaintain, and offer acceptable flame spreadproperties.

Enclosures and Barriers

Enclosures and barriers block and reflect direct-radiated sound from a noise source. A barrierprovides a “shadow zone” of sound attenuationbetween the source and the receiver, much aslight casts a shadow behind a wall. Full enclosuresmay be used around the source or around thereceiver (e.g., personnel in affected areas). Partialbarriers may be used to protect noise sensitiveareas, by locating receivers in the shadow zone.The effectiveness of a barrier in blocking noisetransmitted through it is a function of its soundtransmission characteristics. Both enclosures andbarriers should be lined with absorptive materialto be fully effective. In the case of an enclosurewithout absorption, the reverberant field insidethe enclosure can greatly increase the interiorsound pressure so that noise outside the enclo-sure is also increased. In the case of a barrierwithout absorption, the noise is simply reflectedelsewhere. Transmission loss and absorption arethe main selection criteria for barriers and enclo-sures, and each is a function of frequency.Openings in enclosures should be acousticallytreated, for maximum effectiveness. Also, whenusing sound barriers it is important to control“flanking path” (sound paths around the barrier).There are many types of commercially availableenclosures and barriers. Complete enclosures forspecific types of mechanical equipment are avail-able, some of which include silenced air inlets/exitsand a reactive silencer for exhaust noise. Severaltypes of modular panels are available that mayinclude sound absorbing material on one or bothsides of the panel. Outdoor barriers, designed toresist wind and seismic forces, are also availableto block or reflect noise outdoors.Along with acoustical performance, practicalissues must be considered in using barriers orenclosures. Engine enclosures require ventila-tion to dissipate the heat that builds up within theenclosure. The enclosure must be accessible formaintenance and inspection and may requirepanic latches on doors. Acoustic materials withinthe enclosure must be fire-resistant.

Structure-borne Noise ControlThe purpose of a vibration isolation system(whether simple or compound), or a wave bar-rier, is to control the transmission of structure-borne noise from the engine unit to the buildingstructure, either directly or through the ground.

Those measures are intended to control noiseclose to the source, where control measures gen-erally are most effective. However, even witheffective isolation mounting of the engine unit itstill may be necessary to provide additional struc-ture-borne noise attenuation in the buildingconstruction. The simplest way to attenuatestructure-borne noise along a path (at least con-ceptually) is to increase the distance between thesource and receiver, since the amplitude of struc-ture-borne noise decreases with increasing dis-tance from the vibration source. The attenuationof noise in concrete-frame buildings has beenfound to be about 5 dB per floor for frequenciesup to 1000 Hz. Attenuation for vibrations travel-ing along continuous concrete floor slabs typi-cally range from 1.5 to 2 dB/meter. In general,there is less attenuation along horizontal build-ing structures.

Another way to attenuate structure-borne noiseis through structural discontinuities. A disconti-nuity, or impedance mismatch, causes a reflec-tion of energy back toward the source, therebycontrolling noise transmission. Such discontinu-ities are usually filled with a resilient material toprevent debris falling into and “shorting out” thegap. Semirigid fiberglass board is normally usedto fill wall gaps, while asphalt-impregnated fiber-glass board is normally used between on-gradeslabs, foundations, and footings. Many times,large buildings already incorporate expansionjoints to allow for thermal expansion and con-traction. These may be used to attenuate struc-ture-borne noise by placing the source andreceivers on opposite sides of the expansion joint.It is essential that construction elements, pipes,or any other rigid connections do not bridge thesediscontinuities.

In addition to the source and the path, receiverlocations can also be treated to control structure-borne noise in some situations. For example,a “floating floor” construction may be used toisolate the receiver (e.g., a person or some pieceof vibration-sensitive equipment) from buildingvibration.

LEBW1414-00 76

Foundation

Foundation Design is a very important and oftenoverlooked aspect of large-engine unit facilitydesign. Large-engine units, as noted above, emitrelatively strong low frequency energy — struc-ture-borne as well as airborne. If the facility designdoes not account for both forms of noise, it is likelythat site noise criteria will not be met. (Foundationdesign for installations where noise is not an issueis discussed in the Mounting section.)

Unfortunately, structure-borne transmission andradiation is much more difficult to analyze thanairborne noise. Whereas it may be relativelystraightforward to estimate the airborne noisetransmission loss of the building structure andvarious types of noise control systems, andthereby assess the adequacy of a facility design,reliable quantitative estimates of structure-bornenoise transmission may be extremely difficult orimpossible to obtain with current technology,particularly at low frequencies. Thus, the usualapproach for noise-sensitive installations is toover-design for structure-borne noise, to ensurethat it is not a problem. This means taking careto control every possible structure-borne noise

path. Especially in this area, designers are stronglyurged to consult qualified professional noise con-trol engineers for noise-sensitive installations.

Engine units usually are mounted on concretepad or metal deck foundations, using the springmounts between the unit base and the founda-tion. Some of the smaller engine units come withisolators between the engine/generator and baseand do not require additional spring mounts forthe unit base. Since the unit base provides suffi-cient stiffness for alignment and relative deflec-tion of the engine and the driven equipment,there is no need to rely on the foundation for addi-tional stiffness. Thus a foundation that is ade-quate for supporting the static load of the unitwill be satisfactory for many installations wherenoise is not a critical concern.

In installations where noise is a major concern,attention must be directed toward all elements ofthe isolation system and to the structural pathsbetween the foundation and the rest of the build-ing structure. Adequate isolation often can beachieved with a simple system, but some instal-lations may require a compound isolation system.

77 LEBW1414-00

The purpose of the governor is to control thediesel engine speed by regulating the amount offuel injected.

Diesel engines that do not have to meet emis-sions standards typically utilize a hydra-mechan-ical (or hydraulic) governor and mechanicallyactuated unit fuel injection systems. This gover-nor regulates speed by controlling the position ofthe fuel control rack. The speed control lever onthe governor is positioned by the operator usingsome type of control lever, cable, or remote airactuator. Devices such as air-fuel ratio controls,shutdown solenoids, and manual shutoffs alsooperate on the governor.

Most diesel engines that meet emissions stan-dards utilize an electronic governoring and con-trol system. The Electronic Control Module (ECM)is engine mounted and used in conjunction withunit fuel injectors that are electronically controlled.This governor regulates speed by controlling theactivation of the electronic solenoid on the unitfuel injector. Speed setting can be remotely setwith various electrical devices. Functions suchas air-fuel ratio, shutdown function, and altitudesensing are electronically controlled in the ECM.See the section on Electronic Governing andControl System for further information.

Speed Droop GovernorsIf the speed of an engine drops from no load to fullload operation, the governor is said to have speeddroop. Speed droop is expressed as a percentageof full load speed. For example, a 10% speeddroop governor with a full load speed of 1200 RPMwould have a no load speed of 1320 RPM.

SPEED DROOP GOVERNOR

Figure 6.1

Speed droop hydra-mechanical governors avail-able on Caterpillar Engines are not all the samein construction, but their speed droop character-istics are the same. They are generally availablein approximately 3% or 8% versions, Figure 6.1.

Load sharing between engines — Mechanical rigs

Engines on a direct drive mechanical compoundmust have load sharing, i.e., they must have speeddroop. Without droop, it is not possible to bal-ance the load between engines, with the result thatone engine will tend towards full fuel and the otherengine will tend towards fuel off. This is true evenfor ECM controlled engines which have anadjustable feature called Top Engine Limit, TEL.TEL equipped engines provide speed droopunder certain operating conditions, but not underthe range of conditions encountered on directdrive mechanical compounds.

Engines on a mechanical compound, but witheach engine equipped with a torque converter, canoperate successfully with Zero speed droop in thegovernor. The “slip” in the torque converter allowsthe load to balance between engines, assumingthe engine speed settings are close to each other.

SHUTOFFSHAFT

LOCATION FORSHUTOFFSOLENOID

AIR-FUELRATIOCONTROL

THROTTLESHAFT

GOVERNORS

Load sharing between engines —Generator sets

Lite plants on mechanical rigs are typically 3%speed droop. They can be 0% speed droop if theyare not operated in parallel, and equipped withoptional hydraulic or electric governors.

Generator sets for SCR drill rigs require 0% (orisochronous) operation. This is accomplishedwith a load sharing isochronous electric gover-nor. These are typically referred to as Wood-ward 2301A load sharing governors — orequivalents. The newer electronic controlledengines have a load sharing module available,but this module is sensitive to the extreme elec-trical noise encountered on SCR drill rigs, plus itcannot be used to parallel with older engines thatare controlled with “master/slave” type load shar-ing control systems. For 3500B engines for SCRrig service, Caterpillar therefore recommends theuse of the “direct fuel control” attachment. Thisallows the engine to be controlled with the 2301Aload sharing governor — or equivalent.

Hydra-mechanicalSpeed Droop Governor

Engines equipped with speed droop governorscan be shut down by rotating the hand throttleshaft beyond a detent into a fuel off position. Amanual shutoff shaft and provisions for mount-ing an optional DC shutoff solenoid are availableon most Cat Engines.

The manual shutoff shaft can have a leverinstalled on it to provide a mechanical or pneu-matic method of stopping the engine whereasthe solenoid option provides for remote electricshut down of the engine.

When operated at less than rated full load speed,the governor speed droop percentage increasesbecause of the reduced flyweight force. Governorsprings should be changed to provide properdroop. If not changed, engine power, response,and load sharing will be reduced.

Air-fuel ratio controls are available as standardor optional equipment for speed droop gover-nors. This control minimizes smoke when accel-erating or applying load to engine. They arerecommended for workover, service rigs, anddrawworks applications.

Air actuator governor controls are available formany engines. Engine shutdown cannot be

accomplished through the air actuator. The airactuators operate between 10 psi to 60 psi(69 kPa to 414 kPa), Figure 6.2.

The air line to the driller’s console must be prop-erly sized for best hoisting response. Too smallor too large reduces response rate.

Customer supplied shutoff and vent valve are rec-ommended as it is an aid during engine servicing.

Figure 6.2

Governor Force and Motion Data

The TMI contains information on (1) arc ofmotion and (2) force level required to operatethe governor speed control on each enginemodel. This allows the designer to select ordesign an appropriate cable control, air control orsome lever-link arrangement if a factory suppliedunit is not available.

Design for Linkage Over-Travel

Non-factory supplied control mechanisms mustbe designed with a stop which prevents over-loading the governor throttle lever when itreaches its limit of travel. But this causes a prob-lem when the stop on the control linkage isreached before full speed position of governorlever is reached. This causes power complaintsbecause the engine is prevented from operatingat rated power, because the linkage did not allowthe engine to develop rated speed.

The best approach is to use a spring-loadedbreakover governor throttle lever which acceptsmotion of the control linkage beyond the travel ofthe governor throttle shaft. It is easy to adjust cor-rectly and visually check that the governor speedcontrol lever will travel its full range.

Engine Shutdown Control

Engine shutdown is done by shutting off the fuelsupply in some manner. Usually this is done witha direct mechanical connection which pulls therack to shutoff, or with a solenoid which does the

To DRILLER’S CONSOLE

SHUTOFF ANDVENT VALVE

AIRACTUATOR

LEBW1414-00 78

79 LEBW1414-00

same thing. Safety shutoffs are discussed morecompletely in another chapter.

The 3300 and 3400 hydra-mechanical gover-nors are available with an attachment 24V DCspeed trim adjusting motor. This feature is oftendesirable on generator set service, Figure 6.3.

Figure 6.3

SHUTOFF SOLENOID

MECHANICALSHUTOFF LEVER

GOVERNORCONTROL MOTOR

HANDLE FOR MODESELECTION ANDMANUAL CONTROL

LINKAGE

Isochronous GovernorsIsochronous governors are usually referred to as“constant speed” or “0% speed droop.” Their no-load and full-load speeds are the same.

The isochronous governors used by Caterpillar arethe Woodward PSG and 3161. These governorsare serviced by Caterpillar, Figures 6.4 and 6.5.

Although these governors are isochronous, theycan be adjusted to provide 3% speed droop,(8% on 3161). The speed droop adjustment isexternal on the PSG and internal on the 3161.

PSG GOVERNOR

Figure 6.4

The PSG governor, which operates on engine oil,is available for smaller generator set engines andis normally supplied with an electric speedchanging motor.

The 3161 is supplied on the 3508, 3512, and3516 for mechanical rig service. It has features

similar to the Caterpillar speed droop governors.The 3161 is supplied with a 10 to 60 psi (69 to414 kPa) air actuator for drill rig service.

A shutoff and vent air valve should be added intothe governor air signal line near the engine,Figure 6.2. This allows a serviceman to hold theengine at low speed, if desired.

3161 GOVERNOR

Figure 6.5

Additional Isochronous Governor Features

Engines equipped with isochronous governorscannot be shut down by use of the governor con-trol. These engines contain a manual shutoff pro-vision. PSG-equipped diesel engines have ahand-operated shutoff lever mounted next to thegovernor. Diesel engines equipped with the 3161governors have a hand-operated shutoff plungerlever located near the governor.

2301A Standby Governor

For standby generator sets, a 2301A Governor isstandard on most engines. The control box doesnot allow parallel operation, Figure 6.6. Thisgovernor provides faster response than speeddroop governors. An EG3P or EG6PC actuatoris mounted on the engine, Figure 6.7.

NONPARALLEL CONTROL (STANDBY)

Figure 6.6

Electric Load Sharing GovernorsA Woodward 2301A electric load-sharing gover-nor system is available on most CaterpillarEngines, Figure 6.9, including 3500B SCR rigunits with the “direct fuel control” feature added.It is isochronous and provides automatic andproportional load division between paralleled ACgenerators and still maintain isochronous speed.

An EG3P or EG6PC actuator is mounted on theengine, Figure 6.6. They require a 0 to 200 mAinput signal. The 3500B with “direct fuel control”also requires this same 0 to 200 mA input signal,but includes a coil that simulates the current inputrequirements of the EG3P or EG6PC actuator.

The load sharing 2301A is recommended forSCR drives. Isochronous hydraulic governorscannot maintain proper load division during thelarge load swings when tripping (operating thedrawworks).

Speed adjustment from the face of the switchgearcan be provided by using a sealed 50 ohm rheo-stat. Engine shutdown from the switchgear canbe accomplished by connecting a pushbuttonacross the min-fuel terminals of the governor,except on 3500B series. A manual shutoff is alsoprovided at the engine.

SCR control systems, provided by many SCRsystem suppliers, contain a load-sharing gover-nor integral with the switchgear circuitry and isreferred to as a “master/slave” control system.Though these systems provide essentially thesame features as the 2301A Governor, Caterpillaris not responsible for aspects of these systems.

AIR-FUELRATIO CONTROL

PNEUMATICSPEEDCONTROL

THROTTLESHAFT

LEBW1414-00 80

81 LEBW1414-00

Duplex mud pumps cause a cyclic load fluctua-tion occurring at the pump stroke speed. Thiscyclic load will cause a cyclic reading on the fre-quency meter plus a cyclic motion of the enginefuel control.

EG3P or EG6PC ACTUATOR

Figure 6.7

2301A Governor Control UnitInstallation/Environment

Mounting

Mount control unit at a location of minimumvibration with four 1/4-20 bolts (6.4 mm) (lengthas required) through the 5/16 in. (7.9 mm)mounting holes in the plate assembly.

For ease of adjustment, control unit should bemounted so switchgear electrical indicatinginstruments are readable when making governoradjustments.

For stable speed control, control unit ambienttemperature must remain constant and be withina –60°F to +150°F range (–50°C to +65°C). Asa general rule, mount the voltage regulator higherthan the governor to minimize temperaturebuildup within the switchgear cubicle.

Do not expose control unit to intense AC mag-netic fields like electrical buses or circuit break-ers. Speed droop or actuator instability can occurdue to the erroneous signals picked up. A solidmetallic barrier should be used between the gov-ernor compartment and circuit breaker and/orbus area.

WIRING DIAGRAM — STANDBY CONTROL

Figure 6.8

NOTE A: Lube oil idle speed switch maintainslow idle speed until oil pressurecloses switch. Another switch may beadded in series for low speed controlat the switchgear.

NOTE B: Approximately 1% speed change per20 ohms. 250 ohms maximum remotespeed settling potentiometer.

NOTE C: 20K droop potentiometer. Leave openif not used.

NOTE D: 2 second acceleration time per50 MFD. Leave open if not used.

NOTE E: Shielded wires should be twistedpairs.

NOTE F: Ground battery negative to switch-gear frame and neutral bus.

NOTE G: Run shielded cable from componentto component. Do not run through ter-minal points. Ground shielded cableat control box only.

NOTE H: Installed on engine by Caterpillar Inc.

NOTE J: Speed range of magnetic pickup1800-5400 hz.

NOTE K: All external wiring to be furnishedby customer.

LEBW1414-00 82

Wiring

Since the 2301A system is designed to be sen-sitive to small signal changes, certain input linesmust be shielded from picking up stray signalsfrom adjacent equipment. Shield all lines indi-cated in the wiring diagram, Figures 6.8 and6.10, and do not run shielded lines in the sameconduit with heavy current carrying cables.

As Figure 6.10 indicates, the paralleling linesshould be closed through contacts of an auxiliaryrelay. The recommended contacts are sealed,mercury wetted, dry reed or equivalent.

Electrical noise can be picked up if the parallel-ing lines go direct to the circuit breaker. Also, cir-cuit breaker auxiliary contacts sometimes providepoor connections to the extremely small mV/mAsignals that flow through paralleling lines.

To minimize electrical interference, the requiredshielded cable must be run from component tocomponent, not through terminal points. Allshields must be grounded only at the control boxbecause it is a ready reference point. Shieldedcable must not have an outside metal sheathwhich could cause a multiple ground. The bat-tery negative and shielding of various cables mustconnect to a common point to provide effectivegrounding. See the section labeled Electrolyticand Galvanic Action Protection for further infor-mation when in a marine environment.

As with any electrical component, the control unitmust be mounted in a dust-free environment.

Wiring to governor components should be16 gauge or larger stranded wire.

A control battery and battery charger are requiredfor the governor system. The control battery is

used only during undervoltage or dead bus con-ditions. Normally, the battery charger float chargesthe battery and operates the governors. Recom-mended system contains one battery set and twobattery chargers. Battery chargers should befused separately and on the emergency genera-tor circuit, if so equipped. If battery maintenancepresents a problem, a nickel cadmium batteryshould be used. A nickel cadmium battery rat-ing equivalent to 2 ampere-hours (7200 Coulomb)per engine is sufficient for four hours runningwithout either battery charger operating. Withlead-acid batteries, a capacity of 10 ampere-hours (36 000 Coulomb) per engine is required.

Condition of control batteries should be periodi-cally checked. Lead-acid batteries should bechanged on a regular schedule.

It may be desirable to have a low voltage alarmset at 22V on a 24V system.

On land rigs, the battery should be disconnectedduring rig moves to prevent discharge.

A battery charger or Power Pak by itself is notrecommended. The governor is unstable duringlow voltage transients. Also during a dead buscondition, engines would shut down due to nogovernor power input.

If electric starting is used on standby units, thatstandby battery can be used to operate that gov-ernor; however, no other engine governor orstarter can be connected to it. The voltage dipduring cranking will cause instability on any 2301Aequipped engines that are running. If the standbygenerator will run in parallel with main generat-ing units, cranking battery must be separate fromcontrol battery.

PARALLEL CONTROL (LOADSHARE)

Figure 6.9

2301A WIRING DIAGRAM — LOAD SHARING CONTROL

Figure 6.10

NOTE A:All external wiring, contacts and potentiome-ters to be furnished by customer.

NOTE B:Run shielded cable from component to com-ponent, not through terminal points. Groundshielded cable at control end only.

NOTE C:Governor paralleling contacts (terminals 10and 11) are closed simultaneously with gen-erator circuit breaker by an auxiliary circuitbreaker contacts directly, but through a relaysolenoid.

NOTE D:Ground battery negative to switchgear frameand neutral bus.

NOTE E:Load sensor input voltage (terminals 1through 3) may be either 120 or 208 volt AC bysimple reconnection of load sensor trans-formers. (Reconnection Terminal Board). Allunits shipped for 208-volt AC connection.

NOTE F:On 3500B with “Direct Fuel Control,” this con-nects to terminals 01 (+) and 02 (–) of the 40pin connector at the bottom of the EngineInstrument Panel.

NOTE G:Ramp switch connected to terminals 14 and15 is engine-mounted oil pressure switchwhich maintains low idle speed until oil pres-sure closes switch. Another manual switchmay be added (in series) for low speed con-trol at switchgear.

NOTE H:Optional shutdown switch(es) may be con-nected to terminals 22 and 23 for remote shut-down at driller’s console, at switchgear, etc.

NOTE I:Governor may be operated in parallel, withoutcarrying load if required, by wiring load shar-ing control switch as shown (switch shown innon-load sharing position).

NOTE J:A switch may be connected and labeled as:

Position Connection

1. STOP Shutdown SwitchNote H

2. LOW SPEED Ramp SwitchNote G

3. FULL SPEED Load Share SwitchNote I

4. LOAD SHARE Load Share SwitchNote I

83 LEBW1414-00

Miscellaneous

A load-sharing control switch can be used whereit is desired to remove load from the enginebefore opening the generator circuit breaker. Thisreduces wear on the circuit breaker and mini-mizes transient speed changes. In full speed posi-tion, engine load is reduced to less than 10%. SeeNote I, Figure 6.10.

Electronic Governing and Control System

The Electronic Control Module (ECM) is a fullrange electronic governor. It is a computer andhas full authority over engine fuel delivery.Injection timing is varied as a function of operat-ing conditions to optimize engine performancefor emissions, fuel consumption, and ease ofoperation. The electronic system also includesmechanical or hydraulic actuated electronicallycontrolled unit fuel injections (MEUI or HEUI),the wiring harness, switches, and sensors. Thepersonality module is the software for the ECM.The ECM is engine mounted and cooled withdiesel fuel. See Figure 6.11.

Figure 6.11

The ECM monitors many engine parameters, andgenerates diagnostic codes, as required. ThisECM data becomes the source for the data dis-played on the engine instrument panel. Electroniccontrolled engines have a self-diagnostic capa-bility. In addition to monitoring the engine with

various sensors and transducers, the ECM detectsunintentional grounds, shorts, and open circuits,thereby saving time during diagnosis of engineproblems. The engine’s electronics stores recordsof past performance. This will allow troubleshoot-ers to see if operation contributed to problems.

The ECM also provides cold start modificationsto injection timing. This provides reduced smokeand reduced engine warm-up time.

Installation wiring diagrams and programmingfeatures vary somewhat between the variousengine models. For specific and complete infor-mation, consult the proper Installation guide.These presently are:

SENR1025-03, for 3176C, 3196, 3406E,3456, 3408E & 3412E

LEMB7301-00 for 3500B series engines.

Alarm, Derate, Shutoff Options

The ECM monitors functions such as exhausttemperature, air cleaner restriction, water tem-peratures, and crankcase pressure continuously.If important parameters enter into a dangerouscondition, the engine can protectively respond invarious ways.

Alarm mode provides alarm only for monitoredengine parameters. Derate mode will alter engineRPM or hp when specific operating parametersare exceeded. Shutdown mode will shut down theengine when specific operating parameters areexceeded. For example, it may derate itself sev-eral percent every few seconds/minutes to pro-tect itself from unplanned down time. Consult thespecific Installation Guide for specific details.

With proper communication links and software,real time or historical data can be accessed andremotely displayed or analyzed.

Programming Parameters

Many programmable parameters affect engineoperation. Certain parameters affecting engineoperation may be changed with an ElectronicService Tool, (ET). Some parameters may affectengine operation in ways an operator may notexpect. Parameters are stored in the ECM andmay be protected from unauthorized changes bypasswords. Certain parameters are accessibleonly with Factory Passwords. Other parametersare accessible with Customer Passwords. Refer tothe specific Installation Guide for details.

ECM

LEBW1414-00 84

Auxiliary switch requirementsAll non-Caterpillar provided switches connectedto the electronic control system must be two wiredesign and externally connected to the batterynegative. Internally grounded or case groundedswitches must not be used.Applied voltage to switches by the ECM will nor-mally not exceed 12 VDC. Switch contact platingshould not corrode or oxidize. Gold plated switchcontacts are recommended. Normal current drawthrough the switches by the ECM will not exceed5.0 mA.

Pin Connector RequirementsAll connections to the electrical control systemare through pin type connectors. Field addedwiring should be tested with a 45 N (10 lb) pulltest on each pin/wire. This test ensures the wirewas properly crimped in the pin, and the pinproperly inserted into the connector. (Do not sol-der wiring connections.)All unused connector socked slots must be sealed.

Wiring Harness RoutingAll wiring connections have connector seals tokeep out water and other contaminants. Wiringadded should not have short radius bends or ten-sion on the connectors. Routing of all harnessesshould ensure that connector seals are not stressedbecause the harness wiring curvature is too closeto the connector. See Figure 6.12.

Figure 6.12

Battery Circuit Requirementsand Considerations

Proper grounding for the engine electrical sys-tems is necessary for proper performance andreliability. Improper grounding results in unreli-able electrical circuit paths. That may damagemain bearings, crankshaft bearing journal sur-faces, and aluminum components. Stray electri-cal currents can also cause electrical noise whichdegrades control and system performance.These problems are often very difficult to diag-nose and repair.

The customer must provide an AWG 4 (or larger)ground wire from the engine Electronics GroundStud to the battery negative. All ground pathsmust be capable of carrying any conceivablefault currents. An AWG 4 (or larger) wire is rec-ommended to handle alternator currents. Thealternator and other electrical loads should begrounded at the same point (starting motor neg-ative or battery negative) to avoid stray electri-cal currents. Grounding through frame membersis not recommended.

Use of an alternator or battery charger without abattery is not recommended as a power sourcefor electronic engines. The battery provides noisesuppression in addition to starting capability forthe engine.

Certain smaller engines can operate on 12 VDCsystems. Larger engines require 24 VDC. Theacceptable voltage range is 20 to 28 VDC. Lowervoltage will first cause the loss of instrumenta-tion but the engine may keep operating with thevoltage as low as the 10 VDC. This is not rec-ommended for normal operation.

A temporary loss of power (as in one or two milli-seconds when switching) will not affect engineoperation. A loss of DC power for a longer period(over 0.25 second) will cause the engine to stoprunning, depending upon injection duration andother loads on the ECM.

3500B engines require a power source of 24 VDC10 Ampere continuous, 20 Ampere intermittent,clean electrical power source.

Welding on an Electronic Engine

Before welding near an electronic engine, the fol-lowing precautions should be observed:

— Turn the Engine Control Switch to the OFFposition.

HARNESS CORRECTLYROUTED

WIRE EXITING STRAIGHT OUTOF CONNECTOR CORRECTLY

WIRE EXITING PULLEDUP ON CONNECTOR

INCORRECTLY

HARNESS PULLED TOWARD CENTERTOO CLOSE TO CONNECTOR

HARNESS PULLED UPTOO CLOSE TO CONNECTOR

INCORRECTINSTALLAT ION

CORRECTINSTALLAT ION

85 LEBW1414-00

LEBW1414-00 86

— Disconnect the NEGATIVE battery cable atthe battery. If a battery disconnect switch isprovided, open the switch.

— Disconnect the ECM harness connectors.

— Connect the welder ground cable directly tothe member being welded. Place the groundcable clamp as close as possible to the weldto reduce the possibility of weld current dam-age to bearings, hydraulic components, elec-trical components and ground straps. Do notuse electrical components, the ECM, orElectronics Ground Stud for grounding of thewelder.

— Protect wiring from welding debris or splatter.

— Use standard welding techniques to weld thematerials together.

Suppression of Voltage Transients

Caterpillar recommends transient suppression atthe source of the transient. Inductive devices suchas relays and solenoids can generate voltagetransients on control system inputs, and degradeelectronic control system performance. Fieldinstalled relays and solenoids should includebuilt-in transient suppression diodes where pos-sible. See Figure 6.13.

Figure 6.13

Throttle Position Sensor —Non-generator Sets

The Throttle Position Sensor (TPS) eliminates themechanical throttle and governor linkages. TheTPS utilizes operator lever movement and sendsan electrical speed signal to the engine ElectronicControl Module (ECM). The TPS signal, alongwith the speed/timing signal is processed by theECM to control engine speed.

The TPS signal is a Pulse Width Modulated (PWM)signal. See Figure 6.14. Note that ‘0’ signal doesnot stop the engine, but lets engine operate at a

pre-programmed low speed. The TPS can be fit-ted with a pneumatic operator for control.

SPEED CONTROL WITH PWM INPUT

Figure 6.14

Direct Fuel Control — 3500B Gen Sets

Control of 3500B gen sets is recommended withan optional 0-200 mA engine governor conver-sion. This provides for control by the 2301A typeload sharing control. It allows for parallel opera-tion with non-3500B gen sets, including opera-tion in systems with master-slave controlschemes. Also see Note F in Figure 6.10.

The Direct Fuel Control disables the governorsystem in the ECM. Low idle and overspeed func-tions are retained. 0 mA control returns the engineto the ECM set low idle, not to engine stop.Shutdown can be done at the engine or by wiringin a remote routine stop switch.

Data Connections

The ECM provides output pins that are dedicatedto the communications data link. The data link isavailable to share data between the ECM, elec-tronic service tools, and electronic display mod-ules. See the specific Installation Guide for details.

Generator Set PerformanceA governor should provide a stable speed controlwhen the load remains constant, Figure 6.15.

This is unrelated to any particular speed, but ismerely a tolerance on speed at any steady load.Caterpillar governors have a steady-state speedtolerance of ± 0.33%, while Woodward governorsoffer ± 0.25%.

Transient speeds are temporary excursions (dipsor overshoots) from steady-state speeds causedby sudden imposition or detraction of load.

0 5 10 90 95 100

100% (Programmed

High Idle)

0% (Programmed

Low Idle)

Throttle Position %

5% “Deadband” Insures engine will reach Low and High Idle

Engine drops to Low Idle and a fault is logged

THROTTLE POSITION VS. PWM INPUT

POWER POWER

87 LEBW1414-00

Wherever a load is applied to or removed from agenerator set, the engine speed rpm, voltage andfrequency are temporarily changed from itssteady-state condition. This temporary changeis called transient response. When a significantload is applied, the engine speed temporarilyreduces (generally referred to as frequency orvoltage dip) and then returns to its steady-statecondition. The degree of this dip depends on theamount of active power (kW) and reactive power(kVAR) changes based upon total capacity anddynamic characteristics of the generator set. Onremoval of load, the engine speed increasesmomentarily (generally referred to as overshoot),then returns to its steady-state condition. Thetime required for the generator set to return to itsnormal steady-state speed is called recovery time.This is illustrated graphically in Figure 6.15.

Generator sets on offshore rigs have to meet thetransient response requirements of the variousmarine classification societies. These require-ments are demonstrated on a resistive load bankwith various step load changes.

In addition, jackup drill rigs can impose large ACmotor block loads with their leg jacking systems.(See the section on motor starting.) Typically,other AC motors on land or offshore rigs do notpresent significant transient response challengesdue to the size of these motors in comparison tothe engine and generator capacity.

The DC motors, powered through the SCR con-trol system, are considered to be “soft-start.” Theseverest transient DC load (but of short duration)

on a drill rig is applied by the drawworks when lift-ing “empty blocks.”

Motor Starting

The gen set’s ability to start large AC motorswithout large frequency or voltage dips dependson the entire system. System factors include:

• Available engine power

• Capacity of the generator

• Energy stored in the rotating inertia of thegen set

• Acceleration of the motor and its load (motorcharacteristics).

A properly sized generator will support the highstarting kVA (skVA) required and sustain ade-quate output voltage for the motor so it can pro-duce the needed torque to accelerate its load torated speed.

After the initial voltage dip, it is important thatthe generator restore voltage to at least 90% todevelop adequate torque to accelerate its load torated speed. Full voltage starting causes thelargest voltage dip.

Voltage Regulators

The voltage regulator is a key component indetermining the amount of voltage/frequencydeviation and recovery time on the AC motorportion of the load, such as when “jacking up” ajackup drill rig or when performing load bank

Figure 6.15

acceptance testing. There are several differenttypes of regulators:

• Constant voltage

• Volts/Hertz (Caterpillar standard)

• 2 Volts/Hertz

• Digital Voltage Regulator (adjustable Volts/Hertz)

A constant voltage regulator attempts to maintainrated voltage as the load is applied. Since thegenerator is maintaining rated voltage, eventhough the speed has reduced, it is maintainingthe applied AC load (ekW). This results in anincreased RPM drop during large AC load changes.

Constant voltage regulators are the most com-mon regulation system on drill rigs. Some offshorerigs have begun to use Volts/Hertz (Volts-per-Hertz) regulation systems to improve stabilityand transient response during certain non-drillingfunctions. The voltage temporarily reduces whenthe speed drops during the starting of large ACmotors. This voltage reduction improves theoverall voltage and frequency recovery time.

Digital Voltage Regulators are programmable tocompensate for changes in the inertia of theengine generator and local load requirements. Itwill provide constant voltage control, withVolts/Hertz operation when under frequency.

LEBW1414-00 88

89 LEBW1414-00

General InformationA No. 2 diesel fuel, when mixed with the properamount of air and compressed to the ignition tem-perature, will produce in excess of 19,500 Btu/lbof heat energy (45,5000 kJ/kg).

As a general rule, 38% of this energy will be usedto produce useful work, 30% will be dischargedinto the exhaust system, 27% will be rejected intothe engine cooling system, and 5% is radiated tothe environment.

The cooling system has a direct effect on theoperation and service life of the engine. If thecooling system is not correctly sized, does nothave good maintenance, or is not operated cor-rectly, the engine can overheat or overcool. Thiscan shorten the engine service life and/or resultin poor engine performance.

Caterpillar oilfield Engines are equipped with thebasic components required for a closed circuitcooling system. A closed system recirculates thecoolant. The components are all engine mountedwith the exception of the water system heatexchanger or radiator. These two items may bemounted on the same oilfield base. DO NOT usesea water or impure untreated water in the jacketsystem as it causes corrosion.

Caterpillar oilfield Engines are designed to oper-ate with a jacket water temperature differentialof approximately 18°F (10°C) measured acrossthe engine under full load. Coolant entering the

block should be a minimum of 165°F (74°C).Coolant will exit at 175° to 210°F (79° to 99°C),depending on inlet temperature, load, temper-ature regulator, and pressure. Cooling systempressure determines maximum allowable tem-perature. 200°F (94°C) is the maximum for non-pressurized systems, and 210°F (99°C) is themaximum for pressurized systems.

Jacket water temperatures are maintained highenough by water temperature regulators to pro-vide efficient engine operation. Light load oper-ation in cold weather, particularly where enginesare not protected from wind, may result in lowengine operating temperatures. Extended oper-ation under these conditions may cause enginedamage.

Maximum jacket water temperature limits arecontrolled by size of radiators or heat exchangers.

Cooling System FunctionsFigure 7.2 shows the basic components of com-mon liquid cooled engine cooling systems. Thesebasic components are: coolant, the water pump,the engine oil cooler, coolant temperature regu-lators, the fan and the radiator. In operation, thewater pump pushes coolant through the engineoil cooler and into the cylinder block. The coolantthen flows through the cylinder block and intothe cylinder head(s) where it flows to the hotareas of the cylinder head(s). Additional com-ponents that will transfer heat to the coolant are

COOLING SYSTEMS

Figure 7.1

AFTERCOOLER WATER OUTLET

RADIATOREXPANSION TANK

JACKET WATER OUTLET

STACKED COREAFTERCOOLERCIRCUIT

LEBW1414-00 90

aftercoolers, water cooled exhaust manifolds,water cooled turbocharger shields and housingand torque converter oil coolers. After flowingthrough the cylinder head(s), the coolant goesinto the coolant temperature regulator housing.

Figure 7.2

When the engine is cold, the temperature regu-lators prevent the flow of coolant to the radiatorand direct the coolant back to the water pumpinlet. As the temperature of the coolant becomeswarmer, the temperature regulators begin to openand permit some flow of coolant to the radiatoror heat exchanger.

The regulator opens to maintain the correctengine temperature. The amount that the regu-lator opens and the percent of coolant flow to theradiator depends on the load on the engine andthe outside air temperature.

Caterpillar provides a radiator or heat exchangerand expansion tank system designed to performsatisfactorily with each engine manufactured andto be compatible with various power levelsselected. Modifications to the cooling packagesare not acceptable without approval because ofpossible disturbance to coolant flow paths.

See Figures 7.1 and 7.3 for typical external com-ponents such as heat exchangers and expansiontanks.

The expansion tank and heat exchanger performthe same function as the radiator. A radiator fanprovides air flow through the cooling fins of theradiator to transfer coolant heat to the air. Anexternal water supply is used to accomplish heattransfer when using a heat exchanger.

Water Temperature Regulators

The thermostat (regulator) and bypass line main-tain proper operating temperature. The regula-tor directs all or part of the water discharged fromthe engine jacket to the cooler. The bypassedcoolant is sent to the expansion tank on heatexchanger cooled engines or to the water pumpinlet on radiator cooled engines where it mixeswith cooled water before returning to the enginejacket. Thermostats with higher operating tem-peratures are available for field installation. Seethe section on Lubrication Requirements for HighSulfur Fuels. Caterpillar Engines equipped forradiator cooling have temperature regulators ina controlled outlet configuration, Figure 7.4.

Most Caterpillar Engines equipped for expansiontank/heat exchanger cooling have the same tem-perature regulators but in a controlled inlet con-figuration, Figure 7.5. This does cause the heatexchanger to be pressurized to the higher JWwater pump pressure.

Operating temperature of the jacket water oninlet-controlled systems will be higher than thatfor the outlet-controlled system by the amountof the temperature rise across the engine.

The jacket water pump has sufficient capacity tomaintain proper flow through the engine whilecirculating water through a heat exchanging cir-cuit with moderate line resistance. An increasein pipe diameter is required when external resist-ance reduces water flow below the required min-imum. Refer to TMI or Engine Performance book.

Aftercooler Designs

The engine aftercooler reduces the temperatureof the charge air provided by the turbocharger.This results in cooler combustion and exhausttemperatures plus reduced engine emissions.

Jacket Water Aftercooling (JWAC)

Figures 7.2 and 7.4 illustrate this configuration.Aftercooler water is the engine jacket coolant. Theaftercooler temperature will be up to 210°F (99°C).

Separate Circuit Aftercooling (SCAC)

In this configuration, the aftercooler water sourceis a separate, cooler source of treated coolant.This configuration is typically designed for anaftercooler inlet coolant temperature of 140°F(60°C). 140°F (60°C) is a practical limit for most

91 LEBW1414-00

radiator cooled applications and provides emis-sion compliance for many engines. This is utilizedon the 3500B series of engines. See Figure 7.1.

In order to ensure emissions compliance in use,optional or customer supplied radiators must becapable of rejecting enough heat to allow properoperation at worst case site conditions and alsomust supply 140°F (60°C) SCAC cooling waterto the aftercooler inlet, with a SCAC flow rate of

at least 140 gpm (530 L/m) with an ambient tem-perature of 86°F (30°C) and at site conditions(including altitude considerations).

Figure 7.6 shows a SCAC radiator with side-by-side cooling sections. This radiator configurationcan work with both suction or blower fan config-urations. On larger engines, radiator width maybecome unacceptably large.

RH VIEW LH VIEW

Figure 7.3

RADIATOR COOLING — CONTROLLED OUTLET THERMOSTATS

Figure 7.4

AC HEAT EXCHANGER

AFTERCOOLERJW TEMPERATURE

REGULATOR

AC TEMPERATURE REGULATOR

AC WATER PUMPJW PUMP

EXPANSION TANK

JW HEATER

JW HEAT EXCHANGER

LEBW1414-00 92

Figures 7.1 and 7.7 show an SCAC radiator withstacked core cooling sections. This radiator con-figuration will only work with a blower fan con-figuration.

SCAC cooling systems include an aftercooler ther-mostat to prevent too cold of coolant in the after-cooler. Cold aftercooler water, at high engine loads,can cause excessive engine cylinder pressure.See Figure 7.8.

Figures 7.3 and 7.5 show the SCAC system usedwith heat exchanger cooling for offshore drillingpower modules. Dual heat exchanger circuitsincludes expansion tanks to provide venting andfilling requirements.

HEAT EXCHANGER COOLING — CONTROLLED INLET THERMOSTATS

Figure 7.5

RADIATOR COOLING — SIDE-BY-SIDE SCAC COOLING SECTIONS

Figure 7.6

PIPINGPART OF ENGINESUPPLIED BY PACKAGEROR RADIATOR SUPPLIER

ENGINE DRIVENJW PUMP

BYPASSLINE

RETURN

OUTLET

JW THERMOSTAT

AC TEMPERATURE REGULATORRA

DIA

TO

R

AC JW AC PUMP

93 LEBW1414-00

Air-to-Air Aftercooling (ATAAC)

In this configuration, the aftercooler core is relo-cated from the engine to the radiator. Coolingwith the ambient air reduces charge air temper-ature. Engines subject to more stringent emis-sions requirements use the ATAAC aftercoolerconfiguration. This is utilized on most of thesmaller Caterpillar electronic controlled engines.

Air piping routes turbocharger outlet air to theATAAC section of the radiator and back to theengine inlet manifold.

If the ATAAC radiator is locally made, the chargeair section must be designed to deliver air to theengine’s air intake manifold at a temperaturespecified for the engine model with ambient airtemperature equal to (77°F) 25°C, maximum airtemperature to turbocharger equal to 97°F (36°C),maximum pressure drop from the turbochargercompressor exit to engine intake manifold of4 in. Hg (13.5 kPa), and zero cooling system ramair velocity. Specified inlet manifold air temper-ature and turbocharger compressor exit condi-tions can be found in the TMI. The recommended

RADIATOR COOLING — STACKED CORE SCAC COOLING SECTIONS

Figure 7.7

3500B AC PUMP AND LINES

Figure 7.8

PIPINGPART OF ENGINESUPPLIED BY PACKAGEROR RADIATOR SUPPLIER

ENGINE DRIVENJW PUMP

BYPASSLINE

RETURN

OUTLET

JW ENGINE THERMOSTAT

AC TEMPERATURE REGULATORRA

DIA

TO

R

AC PUMP

BLOWER FAN

LEBW1414-00 94

charge air cooler location should provide paral-lel air flow through the jacket water radiator andcharge air cooler. If a series (stacked) arrange-ment between the charge air cooler and jacketwater radiator is selected, the charge air coolermust be located upstream relative to the jacketwater radiator, or any other stacked coolers inthe system and special consideration must begiven for core cleaning and servicing.

Connections

Use flexible connections for all connections tothe engine (rubber hoses are not recommended).The positions of flexible connections and shut-off valves are important. Shut-off valves (usedon larger engines) should be located to providea flexible connection and also allow engine repairwithout having to drain the entire cooling sys-tem. Orient the flex connector to take the maxi-mum advantage of its flexibility. When selectingconnectors, consider normal thermal expansionand maximum expected movement.

Material compatibility must also be evaluated.The internal surface must be compatible with thecoolant used over the anticipated operating tem-perature and pressure ranges. The liner material ofthe flexible connection must also be compatiblewith potential coolant contaminants, such as lubeoil and system cleaning solutions. The outer covermust be compatible with its environment (tem-perature extremes, ozone, grease, oil, paint, etc.).

Cooling System Protection

All pipe and water passages external to the engineshould be cleaned before initial engine operationto ensure there will be flow and foreign materialswill not be lodged in the engine or cooler.

Electrical systems should be designed so no con-tinuous electrical potential is imposed on cool-ing system components. Any electrical potentialmay cause cooling system materials to be dam-aged by electrolytic processes.

Galvanic activity in saltwater circuits produces acorrosive action with metal, resulting in deteriora-tion of system components. Proper cathodic pro-tection should be employed by installing sacrificialzinc rods in sea water flow passages at numerouslocations. Sufficient zinc rods are installed onCaterpillar components. In order to maintain thisprotection, the zinc rods must be inspected reg-ularly and replaced when deteriorated. Refer tothe section on Electrolytic and Galvanic ActivityProtection for additional information.

Coolant ConsiderationsProperties

Water is used in the coolant mixture because it isthe most efficient, best known, and universallyavailable heat transfer agent. However, eachwater source contains contaminant levels tovarious degrees. At operating temperatures ofdiesel engines, these contaminants form acids orscale deposits that can reduce cooling systemservice life.

Prime consideration in closed cooling systems isto ensure no corrosion or scale forms at any point.Therefore, select the best quality water available,but never use salt water.

Water hardness is usually described in parts permillion, ppm (grains/gal), of calcium carbonatecontent. Water containing up to 60 parts per mil-lion (3.5 grains per gallon) is considered soft andcauses few deposits.

Treated Water

Never use water alone as a coolant. Supplemen-tal coolant additives are required because purewater is corrosive at engine operating tempera-tures. Corrosion inhibitors or antifreeze solutionadded to water maintains cleanliness, reducesscale and foaming, and provides pH control.

Figure 7.9

AIR

ATAAC SECTION

WATER

JW SECTION

95 LEBW1414-00

A 3%–6% concentration of inhibitor is recom-mended to maintain a pH level of 8.5 to 10. Sud-den changes in coolant composition should beavoided to minimize nonmetallic componentfailure.

Caterpillar cooling inhibitor is compatible withethylene glycol and propylene glycol base anti-freezes but not with Dowtherm 209, or CatExtended Life Coolant (ELC). With a 30% mix-ture of glycol containing corrosion inhibitors, noadditional inhibitors are required. To maintainconstant protection, additives should be replen-ished every 250 operating hours.

For conventional heavy duty cooling systems theantifreeze/coolant is recommended.

NOTE: If cooling water comes in contact withdomestic water supplies, water treatment maybe regulated by local codes.

Coolant/Antifreeze (Glycol)

Glycol in the coolant provides boil and freeze pro-tection, prevents water pump cavitation, andreduces cylinder liner pitting. For optimum per-formance, Caterpillar recommends a 50/50 gly-col/water coolant mixture.

Ethylene glycol is commonly used in heavy duty(HD) coolant/antifreezes. Propylene glycol is alsocommon. Both ethylene glycol and Propyleneglycol have similar fluid properties in a 50/50glycol/water mixture. Both ethylene glycol andpropylene glycol provide similar heat transfer,freeze protection, corrosion control, and sealcompatibility. The following charts define thetemperature protection provided by the two typesof glycol.

NOTE: Do not use propylene glycol in concen-trations that exceed 50 percent glycol because ofpropylene glycol’s reduced heat transfer capa-bility. Use ethylene glycol in conditions thatrequire additional boil or freeze protection.

Exposing engine coolant to freezing tempera-tures requires additional antifreeze. Ethylene gly-col or Dowtherm 209 are recommended to protectagainst freezing and inhibit corrosion. Borate-nitrite solutions such as Caterpillar inhibitor arecompatible only with ethylene glycol and canreplenish the original corrosion inhibitors in theantifreeze.

Figure 7.10 defines the concentration of ethyl-ene glycol required for system protection. It alsodescribes the effect on coolant boiling tempera-ture which reduces coolant afterboil. The concen-tration should exceed 30% to assure protectionagainst corrosion, but above 60% will needlesslypenalize heat transfer capabilities. Generally, aradiator derates 2% for each 10% of antifreeze con-centration. Use of antifreeze year around decreasesradiator capabilities at least 6°F (3.3°C).

COOLANT FREEZING AND BOILING TEMPERATURES VS.

ETHYLENE GLYCOL CONCENTRATION

Figure 7.10

Extended Life Coolant (ELC)

Caterpillar provides Extended Life Coolant (ELC)for use in heavy duty diesel engines, natural gasengines, and automotive engines. The CaterpillarELC anticorrosion package is totally differentfrom conventional coolants. Caterpillar ELC isan ethylene glycol based coolant which containsorganic acid corrosion inhibitors (which turn into

–80

–60

–40

–20

0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

300

320

(°F)

–62

–51

–40

–29

–18

–6

4

15

26

38

49

60

71

82

93

105

116

127

138

149

160

(°C)Temperature

80 90 100706050

%

403020100

FREEZINGTEMP

RECOMMENDEDCONCENTRATIONRANGE 30–67%

(°SEA LEVEL)

BOILINGTEMP

Propylene Glycol

Concentration Protection Against% Glycol/% Water Freezing Boiling

50/50 –20°F (–29°C) 222°F (106°C)

Ethylene Glycol

Concentration Protection Against% Glycol/% Water Freezing Boiling

50/50 –33°F (–36°C) 223°F (106°C)60/40 –60°F (–51°C) 226°F (108°C)

LEBW1414-00 96

carboxylates) and antifoaming agents. CaterpillarELC has nitrites that serve as corrosion inhibitorsthat protect against cavitation corrosion. CaterpillarELC also has TT (toly-triazole, a yellow [non fer-rous] metal corrosion inhibitor). Caterpillar ELChas been formulated with the correct levels ofadditives to provide superior corrosion protectionfor all metals in diesel engine cooling systems.

Caterpillar ELC extends coolant service life to6000 Service Hours or Four Years. CaterpillarELC does not require frequent additions of sup-plemental coolant additives, SCA. A “one timeonly” coolant Extender is the only maintenanceaddition required. The extender should be addedto the cooling system at 3000 Service Hours orTwo Years.

Caterpillar ELC is available Premixed with distilledwater in a 50/50 concentration. The PremixedELC provides freeze protection to –33°F (–36°C).The Premixed ELC is recommended for initial filland for topping off the cooling system. ELCConcentrate is available to lower the freezingpoint to –60°F (–51°C) for Arctic conditions. ELCConcentration should be used to adjust thecoolant freeze point as required where CaterpillarELC Premixed freeze protection is not acceptable.

Contact your Caterpillar dealer for part numbersand available container sizes.

Caterpillar recommends the Extended Life Coolantas it provides extended coolant service life, cor-rosion protection, extended water pump seal ser-vice life, and extended radiator service life.

NOTE: The Caterpillar EC-1 specification is anindustry standard developed by Caterpillar. TheEC-1 specification defines all of the performancerequirements that an engine coolant must meetin order to be sold as an extended life coolantfor Caterpillar engines. Caterpillar ELC meetsthe industry performance requirements ofASTM D4985 and D5345 for heavy duty low sil-icate coolant/antifreezes. Caterpillar ELC alsomeets the industry performance requirementsof ASTM D3306 and D4656 for automotiveapplications.

NOTE: Do not mix ordinary ethylene glycol orpropylene glycol mixtures with ELC. Completelyflush system before converting from one to theother coolant.

Corrosion Resistance

The coolant must prevent the formation of rustand pits in the engine and other components.Since all water can cause corrosion, water aloneis not a good coolant. Both distilled water andsoftened water are unacceptably corrosive whencorrosion inhibitors are not added.

Always add Caterpillar’s corrosion inhibitor,Cooling System Conditioner, or equivalent to thewater antifreeze mixture at the time of the initialfill of the cooling system if the initial fill does notinclude it. (This is not necessary when usingCaterpillar Antifreeze. The Caterpillar formulaincludes all necessary inhibitors for initial fill.) Ifwater only is used (not recommended), it isextremely important that conditioner be added.Use 3P2044, quart (0.118 L), or 6V3542,1/2 pint (0.24 L), Cooling System Conditioner.

Because modern antifreezes contain consider-able dissolved chemical solids to accommodatealuminum components, over-concentrations canreduce heat transfer and cause water pump sealleakage or failure.

NOTE: Do not over inhibit your cooling systemor damage will result.

Chromate Corrosion Inhibitors

Chromate is another corrosion inhibitor. In gen-eral, special testing equipment must be utilized inorder to measure the coolant consist. Inappro-priate amounts of corrosion inhibitor can do harmto the system. These are being phased out ofusage due to toxicity and environmental concerns.

Water Quality and Treatment —Standard Temperature

Usable water for cooling systems must meet thefollowing criteria:

Chloride (CL) 2.4 grains/gal (40 ppm)Maximum

Sulfate (S04) 5.9 grains/gal (100 ppm)Maximum

Total Hardness 10 grains/gal (170 ppm)Maximum

Total Solids 20 grains/gal (340 ppm)Maximum

pH 5.5–9.0Water softened by removal of calcium and mag-nesium is acceptable.

97 LEBW1414-00

Coolant Testing

The coolant should be maintained throughout thelife of the application. Dealers have available lab-oratory testing services which can measure notonly the glycol levels but also the main corrosioninhibiting additives, as well as contaminants.Caterpillar recommends additives be kept withincertain ranges depending on the type of coolantas well as the application. If regular coolant isbeing used, a prescribed dose of Supplementalcoolant Additive or SCA is usually added at250 hour intervals which recharges the corrosioninhibitors in the form of nitrates, nitrites, borates,and silicates. If ELC (Extended Life Coolant) isused, Caterpillar’s Cooling System Conditioneris added which contains a carboxylate or organicacid corrosion inhibitor, nitrites, and other ingre-dients necessary to ensure the coolant remainscorrosion resistant. Overtreatment should alsobe avoided since this can cause problems as well;do not add treatment unless testing shows addi-tive depletion. Caterpillar also has specificationscovering contaminants such as chlorides, sulfates,hard water minerals, as well as dissolved gases.These must be checked by analytical methodssince they can destroy a system even if corro-sion inhibitor additives are in correct proportions.

Coolant Conditioners and Filters

For 3400 Series and smaller engines a cartridge-type chemical coolant conditioner is available.The conditioner reduces potential cylinder blockand liner pitting and corrosion.A. Consult the factory for suitable coolant

conditioners which should be applied andmaintained in accordance with publishedinstructions.

B. If a dry charged additive water filter isselected, the following plumbing recom-mendations should be followed.1. The filter inlet and outlet are ordinary

0.375 in. (9.5 mm) inside diameter rub-ber hoses. Connect the hoses to obtainthe highest possible coolant pressure dif-ferential across the unit. Heater hoseconnecting points at the coolant pumpinlet and the temperature regulator hous-ing are recommended. If uncertain, plumbthe inlet to a point on the discharge sideof the water pump and the outlet to apoint near the water pump inlet.

2. The outlet should be orificed with an0.125 in. (3.2 mm) internal diameter ori-fice. This will prevent excessive coolantflow through the filter which can bypassthe radiator core and reduce effective-ness of the cooling system. Inlet and out-let lines should include shutoff valves sothe filter can be serviced without drain-ing the cooling system.

System Venting

Air and entrained combustion gas must bepurged and/or vented from the cooling system.Air can be trapped in the cooling system at ini-tial fill or enter through combustion gas leakageduring operation. System deterioration or waterpump cavitation will result.

Air trapped in high points of the cooling systemduring initial fill is difficult to purge and requiresventing, Figure 7.11. Entrained combustion gasrequires deaeration capabilities built into the sys-tem. Deaeration is performed by the Caterpillarexpansion tank or Caterpillar radiator top tank. Ifthese deaeration components are not included,custom deaeration must be provided. Centrifugaldeaeration gas separators are available on theaftermarket. Alternatively, see the section onExpansion Tanks for use of enlarged pipe diam-eters for deaeration.

Caterpillar-supplied cooling systems completelyvent during initial fill at rates up to 5 gpm(0.32 L/s). External piping will also vent providedpiping is installed without air traps and no higherthan engine connecting points on heat exchangersystems. Figure 7.12.

The expansion tank (surge tank) must be the high-est point of a radiator cooled system, Figure 7.13.Radiator air venting requirements for each engineare available on request.

A cooling system that will not purge itself on ini-tial fill must have vent lines from the highestpoints of the system to the radiator expansiontank or to the expansion tank of a heat exchangersystem. Lines must enter the tank above normalwater level, have a continuous upward slope, andcontain no air traps. An adequate vent line shouldbe 0.25 in. (6.3 mm) tubing. Caution: The con-stant full level in the expansion tank must beabove all piping. For additional information onradiator cooling, see the section Radiators withExpansion Tanks.

LEBW1414-00 98

Watermaker Installation RequirementsConnecting watermakers to the jacket water cir-cuit of 3508, 3512, 3516 Engines.

The following guidelines are intended to assistthe designer and installer of watermaker systemsto avoid installations which may damage or impairengine operation. These guidelines in no way guar-antee performance of the watermaker system.

Watermaker system performance, as it affectsthe engine, must be verified at startup.

Watermaker performance will depend upon theamount of heat received from the engine. Referto TMI or Engine Performance book for heatrejection and jacket water pump flow data. Thisdata is for the engine at rated load and speed with

fully open thermostats. As load on the engineand/or engine speed decreases, external waterflow decreases. The amount of heat and water-flow available to the watermaker will be approx-imately proportional to the load on the engine.

Watermaker Circuit

Flexible connectors are required on all connec-tions to the engine. Rubber hoses are not rec-ommended and are generally not approved bymarine classification societies. Use of flexiblemetal connectors is recommended.

All connections are to be made external of theengine’s pump, thermostat and bypass system,i.e., between engine and cooler, Figure 7.14. The

INCORRECT PIPING

Figure 7.11

CORRECT PIPING

Figure 7.12

99 LEBW1414-00

engine jacket water bypass line is not to be mod-ified or blocked.

Watermaker piping should not block access toengine fuel and oil filters.

Flow resistance imposed on the jacket waterpump by watermaker and piping from the enginemust not exceed the limits shown in TMI orEngine Performance book.

Shutoff valves in each line to the watermakershould be installed. This also applies for auto-matic systems since it allows deactivating thesystem for servicing.

All external piping must be level, without airtraps, and below the expansion tank or radiatortop tank. All high points must be vented to theexpansion tank/radiator top tank.

CORRECT PIPING

Figure 7.13

Figure 7.14

LEBW1414-00 100

Expansion Volume

When the jacket water volume of the watermakerand piping exceeds the allowable external vol-ume for the engine-mounted expansion tank, anauxiliary expansion tank must be added. Refer toFigure 7.24 for allowable external volume of theengine-mounted tank. (Refer to the section onAuxiliary Expansion Tank if an additional tankis required.) The engine mounted tank isalways required.

Expansion volume required for radiator-cooledengines must be coordinated with the radiatorsupplier. Additionally, a deaerator is required ifwatermaker flow bypasses the deaeration fea-tures of the radiator. Deaerator should be capa-ble of venting air at the rate of 10% of the engine

displacement per minute. The deaerator mustvent to radiator top tank.

Watermaker Controls

Watermaker controls may be either manuallyoperated valves or thermostatically controlledvalves, Figures 7.15, 7.16, and 7.17.

Any failure of watermaker control system (elec-trical, air, etc.) must shut off jacket water flow tothe watermaker and return the flow to the engineheat exchanger.

The watermaker must be connected between theengine jacket water connections and the heatexchanger or radiator. Required flow diverters orconnections are not supplied by Caterpillar.

MANUAL CONTROL SYSTEM

Figure 7.15

AUTOMATIC CONTROL SYSTEM — SERIES FLOW

Figure 7.16

101 LEBW1414-00

AUTOMATIC CONTROL SYSTEM — PARALLEL FLOW

Figure 7.17

For safety, valve(s) in the engine heat exchangercircuit should contain .25 in. orifices (6.35 mm)so there will be a slight water flow in case all valvesare inadvertently left closed. This orifice assureswater flow to actuate engine alarm system.

The thermostat valve, Figures 7.16 and 7.17,should have a temperature setting that will notinterfere with engine thermostats. This valveshould begin to divert water flow to the engineheat exchanger at no more than 190°F (88°C)and be fully diverting at 205°F (96°C) for engineswith outlet controlled thermostats. Engines withinlet controlled thermostats should be 185°F(85°C) and 200°F (93°C) respectively.

If the watermaker cannot handle the full engineheat rejection and/or cannot handle full water flowof the engine, the automatic system, Figure 7.17,must be used. The circuit, Figure 7.17 connectsthe watermaker in parallel with the heat exchangerwhereas the circuit, Figure 7.16, connects thewatermaker in series with the heat exchanger.

It should be remembered the volume of waterflow to the watermaker depends upon load andwatermaker size, up to the engine’s maximumflow limits.

Mixing Tank

When the watermaker is a long distance from theengine or where watermaker requires a constantwater flow, a mixing tank and circulating pumpare required, Figure 7.18.

Do not use a circulating pump by itself becausethe circulating pump head pressure will damageengine thermostats if they are closed.

Although the mixing tank is not Caterpillar sup-plied, it can be used with any of the suggestedcircuits.

An auxiliary electrical heater may be installedas shown.

Interconnections of Engines

Central cooling systems utilize a single externalcircuit supplying coolant to several engines.Although separate cooling systems for eachengine is preferable, use of a single radiator or heatexchanger system is possible. Practical experi-ence has shown that only identical engines at thesame loads and speeds can be successfully com-bined in a joint cooling system. A failure on oneengine can adversely affect all engines. For thisreason, interconnected engines should have iso-lating valves. Check valves are required on theoutput line of each engines to prevent recircula-tion through an engine that is shutdown with thethermostats opened.

The cooling system for mixed engines with mixedspeeds, loads and thermostat configuration arevery difficult to design and are rarely successful.They must meet the required criteria (water flow,temperatures, pressures, etc.) for each enginewhile operating in all possible combinations withother units.

LEBW1414-00 102

Figure 7.18

A single auxiliary expansion tank is permissible.It must connect into each engine-mounted expan-sion tank (if so equipped). See the section onAuxiliary Expansion Tank. If a shutoff valve isinstalled between auxiliary expansion tank andeach engine-mounted expansion tank, a 0.5 in.(12.7 mm) line must be connected from belowthe shutoff valve to the top of the auxiliary expan-sion tank. The line should enter above the normalfull water level.

Coolant return header to the engines must belarge enough and so located that no engine jacketwater pump inlet operates in a vacuum.

If auxiliary jacket water pumps are required, referto the section on mixing tanks and Figure 7.18.

SCAC engines require that a separate set ofcommon cooling lines be provided for the after-cooler function.

Heat Exchanger Cooling Systems

Water SpecificationsCaterpillar used two water classifications: freshwater and sea water.

Fresh WaterFresh water refers to drinkable water. Prior tochemical water treatment for engine corrosioninhibiting, it must be in a pH range of 5.5 to 9.0,containing no more than 40 ppm chlorides. Totaldissolved solids must be less than 340 ppm. Totalsulfates must be no more than 100 ppm. Totalhardness must be less than 170 ppm. This is thecooling water that is used within the engine‘sjacket water system.

Sea WaterSea water refers to salt water, river water, lakewater and all waters that do not meet the fresh-water requirement. Heat exchanger componentsin contact with this water should be copper-nickel

103 LEBW1414-00

construction, or equivalent, highly corrosion resist-ant material. This is not the water retained withinthe engine’s jacket water system.

Inboard Heat Exchanger CoolingInboard heat exchangers are recommended foruse with Caterpillar oilfield Engines. Caterpillarinboard heat exchangers are shell and tube-type.Heat is transferred from hot jacket water to coldsea water. Heat exchangers are usually mountedon the oilfield base, but may be mounted directlyon smaller engines.Heat exchanger cooled systems require a seawater pump to circulate sea water through theheat exchanger tubes or plates. It is good designpractice to “always put the sea water through thetubes”. The tubes can be cleaned by pushing ametal rod through them; the shell side requireschemical cleaning which is only available atshore-side facilities.Offshore drill rigs provide the main and standbysea water pumps. Sea water is pumped into apressurized header for use throughout the rig,including the engines.The fresh water is circulated through the heatexchanger shell, across the tubes by the engine-driven water pump.Most shell and tube heat exchangers are of eitherthe single-pass or the two-pass type. This des-ignation refers to the flow in the cold water circuitof the exchanger. In the two-pass type, the coldwater flows twice through the compartmentwhere jacket water is circulated; in the single-pass type only once. When using a single-passexchanger, the cold water should flow throughthe exchanger in a direction opposite to the flowof jacket coolant to provide maximum differen-tial temperature and heat transfer. This results inimproved heat exchanger performance. In a two-pass exchanger, cooling will be equally effectiveusing either of the jacket water connection pointsfor the input and the other for return.Factory supplied 150 gpm (9.5 L/s) two-passheat exchangers are recommended because rigwater header size is reduced. A 150 gpm (9.5 L/s)engine driven sea water pump is NOT available.The rig main and standby sea water pumps mustbe sized to provide flow to a header system thatsupplies all engines.

Engine-mounted heat exchangers require theleast amount of pipe fitting since jacket waterconnections to the heat exchanger are made atthe factory, Figure 7.3. Remote-mounted heatexchangers require connecting jacket water inletand outlet at the engine to shell side of theexchanger.The selected heat exchanger must accommodatesea water temperature and flow required to coolthe engine when operating at maximum antici-pated load with stated temperature differential.

HEAT EXCHANGER TYPES

Figure 7.19

Heat exchangers should always be located at alower level (elevation) than the coolant level inthe expansion tank.

Heat Exchanger Sizing

Occasionally, special applications exist whichrequire an inboard heat exchanger size not avail-able as a Caterpillar unit. When these conditionsexist, it is necessary to obtain a heat exchangerfrom a supplier other than Caterpillar. In order toexpedite the selection of a nonstandard heatexchanger, a Heat Exchanger Selection Work-sheet is included, Figure 7.20. Heat exchangersuppliers will provide information and aid inselecting the proper size and material for theapplication.

LEBW1414-00 104

Heat Exchanger Sizing WorksheetHeat Exchanger Sizing Data

Required by Heat Exchanger Supplier

Engine Jacket Water Circuit:1. Jacket water heat rejection* ________________ Btu/min (kW)

1a. Jacket water engine outlet temperature ________________ F° (C°)2. Jacket water flow* ________________ gpm (L/sec)3. Anticipated sea water maximum temperature ________________ F° (C°)4. Sea water flow ________________ gpm (L/sec)5. Allowable jacket water pressure drop ________________ ft. (m) water6. Allowable sea water pressure drop ________________ ft. (m) water

Drop7. Auxiliary water source h sea water

(sea water or fresh water) h fresh water8. Heat exchanger material h adm. metal

(admiralty or copper-nickel) h cu-ni9. Shell connection size** ________________

10. Tube side fouling factor** ________________

Aftercooler Water Circuit:1. Aftercooler circuit water heat rejection* ________________ Btu/min (kW)

1a. Aftercooler circuit engine inlet temperature ________________ F° (C°)2. Aftercooler circuit water flow* ________________ gpm (L/s)3. Anticipated sea water maximum temperature ________________ F° (C°)4. Sea water flow* ________________ gpm (L/s)5. Allowable Aftercooler Circuit ________________ ft. (m) water

Water Pressure Drop*6. Allowable sea water pressure drop* ________________ ft. (m) water7. Auxiliary water source h sea water

(sea water or fresh water)* h fresh water8. Heat exchanger material h adm. metal

(admiralty or copper-nickel) h cu-ni9. Shell connection size** ________________

10. Tube side fouling factor*** ________________***Refer to TMI (Technical Marketing Information)***Refer to engine general dimension drawing***Fouling Factor, a descriptive quantity often found on heat exchanger specifications, refers to the heat exchangers ability

to resist fouling. As defined in Caterpillar literature, fouling factor is the percentage of the heat transfer surface which canbe fouled without losing the heat exchanger’s ability to dissipate the engine’s full heat load. A factor of 0.0001 – 0001is assumed for sea water systems.

Figure 7.20

105 LEBW1414-00

For a given jacket water flow rate, the perform-ance of a heat exchanger depends on both thecold water flow rate and differential temperature.To reduce tube erosion, the flow velocity of thecold water through the tubes should not exceed6 fps (183 cm/s).

At the same sea water flow rate, the flow resist-ance and the flow velocity will be greater througha two-pass heat exchanger. The heat exchangershould be selected to accommodate the coldwater temperature and flow rate needed to keepthe temperature differential of the jacket waterbelow about 18°F (10°C) at maximum engineheat rejection. Thermostats must be retained inthe jacket system to assure that the temperatureof the jacket water coolant returned to the engineis approximately 175°F (79°C).

Size heat exchangers to accommodate a heatrejection rate approximately 10% greater thanthe tabulated engine heat rejection. The addi-tional capacity is intended to compensate forpossible variations from published or calculatedheat rejection rates, overloads or engine mal-functions which might increase the heat rejec-tion rate momentarily. It is not intended to replaceall factors which affect heat transfer, such as foul-ing factor, shell velocity, etc.

Pay particular attention to the shell side pressuredrop to ensure the entire cooling system flowresistance does not exceed the limitations on theengine freshwater pump.

Maximum Sea Water Temperature

Size heat exchangers such that the seawater isnot heated above approximately 130°F (54°C).Higher sea water temperatures will result in foul-ing of the heat transfer surfaces with chalk-likecompounds.

Temperature rise can be calculated with the fol-lowing formula:

∆ T (deg F) =

Keel CoolersA keel cooler is an outboard heat exchangerwhich is either attached to, or built as part of, thesubmerged part of a ship’s hull. The heated waterfrom the engine(s) circuit(s) is circulated throughthe cooler by the engine driven water pump(s).

This type of cooling system is not widely usedfor oilfield engines. Sufficient ocean currents orriver currents, etc., are not always available tomaintain adequate cooling. They should be usedwith caution as overheating can result.

Keel Cooler TypesFabricated Keel Coolers

Fabricated keel coolers may be made of pipe,tubing, channel, I-beams, angle or other avail-able shapes. The choice of materials must becompatible with materials used in the vessel’shull in order to prevent galvanic corrosion.

Sizing of Fabricated Keel Coolers

Engine water temperature maximum limits arecontrolled by size of the keel cooler. Heat trans-fer rates through any cooler depend mainly oncooling water temperature, cooling water flowand heat transfer surface area. A cooler mayhave to operate at its maximum capacity at zerohull speed. The minimum area calculatedincludes a fouling factor. Materials used in coolerconstruction, condition of waters in which thevessel will operate, and service life expectancywill influence the size selection of a new cooler.See the keel cooler sizing worksheet for aid indetermining size of keel coolers for use withjacket water circuits.

Keel cooler area recommendations contained inthe graphs (Figure 7.21 and 7.22) apply only tokeel coolers made of structural steel (chan-nel, angle, half pipe, etc.) welded to the ship’sshell plating. These recommendations take intoaccount the thermal resistance to heat transferof the steel plate, the internal and external waterfilms, and the internal and external surface cor-rosion factors. The coefficient of heat transfer ofthe fresh water film flowing inside the cooler isbased upon a flow velocity of 3 ft/sec (0.9 m/sec).The coefficient of heat transfer for the raw waterfilm varies with the velocity of water flow past thecooler due to vessel speed. Surface corrosionfactors are based on treated fresh water and pol-luted river water. Miscellaneous factors becomeso predominant in the resultant heat transfer ratethat the type of material used and thickness ofmetal become minor considerations.

Heat Rejection (Btu/min)_______________________Flow (gpm) 2 7.99

LEBW1414-00 106

Normal deterioration of the cooler’s inner andouter surfaces in the form of rust, scale and pit-ting progressively reduce a keel cooler’s effec-tiveness over a period of years. Protective coatingsand marine growths will also reduce the rate ofheat transfer. It can take 4–5 years before dete-rioration stabilizes in keel coolers. It must bedesigned considerably oversize when new.

Because of the severe deterioration of heat trans-fer characteristics associated with structural steelcoolers, adequate cooler size sometimes becomesimpractical. This is particularly true in regions ofhigh sea water temperature (over 85°F [30°C]).In these regions, the use of “packaged” keep cool-ers, or box coolers, made of corrosion-resistantmaterials is suggested. These coolers can provide

KEEL COOLER SIZING WORKSHEETEngine Model __________________ Rating __________________ Hp (kW) at __________________ rpm

For Engine Jacket Water:

1. Jacket water heat rejection* ____________________________________________ Btu/min (kW)

2. Jacket water flow* ________________________________________________________ gpm (L/s)

3. Current speed classification (Refer to Figure 7.22) _____________________________________

4. Anticipated maximum sea temperature ________________________________________ F° (C°)

5. Minimum cooler area required (From Figure 7.22) _____________________________________

Sq ft/Btu/min (m2/kW)

6. Minimum area required (Line 1 times line 5)__________________________________Sq ft (m2)*Refer to TMI or Engine Performance Book. Temperature assumed to be 210°F (99°C).

Figure 7.21

Figure 7.22

.006 .007 .008 .009 .010 .011 .012 .013 .014 sq ft per Btu/min

.032 .037 .042 .048 .053 .058 .063 .069 .074 .079

.015

sq m per kW

35

40

45

50

55

60

65

70

75

80

85

°F

1.7

4.4

7.2

10.0

12.8

15.6

18.3

21.1

23.9

26.7

29.4

°C

Ant

icip

ate

d M

axim

um S

ea W

ater

Tem

pera

ture

Cool er Area Require d

Sti ll W

ater

8 K

nots

and

Abo

ve

3 K

nots

1 Kno

t

(Per Revisi on of 8/11/90)

Thermostats st art open 175°F (79°C) or above

These requirements apply to Keel Coolers made of structural steel only.

Consider use of packaged Keel Coolers made of corrosion-resistant materials where sea water temperature may exceed 65°F (18°C)

107 LEBW1414-00

more heat exchange surface area in a given vol-ume on, or within the hull, than the coolers madeof structural steel.

Expansion TanksFunctions

Expansion tanks perform the following functions:

• Vent gases in the coolant—to reduce corrosion.—to prevent loss of coolant due to dis-

placement by gases.

• Provide a positive head on the system pump.—to prevent cavitation.

• Provide expansion volume.—to prevent coolant loss when the coolant

expands due to temperature change.

• Provide a place to fill the system, monitor itslevel, and maintain its corrosion inhibitingchemical additives.

• Provide a place to monitor the system coolantlevel.

—an alarm switch located in the expan-sion tank will give early warning of cool-ant loss.

Type of Expansion TankEngine-Mounted Expansion Tank(Manufactured by Caterpillar)

The engine-mounted expansion tank provides allof the above functions for the engine’s jacketwater circuit. Caterpillar also provides an expan-sion tank for Petroleum 3500B engine’s auxiliarywater circuit (the aftercooler circuit). It can pro-vide adequate expansion volume for only a mod-est amount of jacket water. Figure 7.24 describesthe allowable external volume using only theengine-mounted JW expansion tank.

The factory-installed expansion tank must beused with the heat exchanger and/or keel cool-ing system. If it is absolutely necessary to removethe engine-mounted tank, consultation withCaterpillar Application Engineering on tank relo-cation and design is recommended. Modifiedexpansion tank performance should be verifiedby testing.

Figure 7.23

Figure 7.23 shows the preferred method of con-necting a remote expansion tank into the enginecooling system. The enlarged section of pipe isnecessary to allow entrained gas to separate outof the water flow.

Expansion Tank Volume

The expansion tank allows for thermal expan-sion of the coolant. In addition to the thermalexpansion, there should also be volume for after-boil and sufficient reserve to allow operation withsmall leaks until they can be repaired. For stan-dard temperature systems, a volume of 15% ofthe total system is sufficient.

Auxiliary Expansion Tank(Jacket Water Circuit)

An auxiliary expansion tank is not requiredwhen an engine-mounted or base-mounted heatexchanger is used. Calculations to determine if anauxiliary tank is required must be made if a remote-mounted heat exchanger, keel cooler, or devicessuch as watermakers are added. Figure 7.24contains data indicating coolant capacity limits ofengine-mounted expansion tanks.

An auxiliary expansion tank provides additionalexpansion volume for the cooling system. Thefunction of this auxiliary tank need not be con-cerned with deaeration and can, therefore, con-sist of a simple tank containing no baffle system.The engine cooling system, including the engine-mounted tank, is designed to provide propersystem venting. Air must also vent from theengine-mounted tank through the connecting

LEBW1414-00 108

pipe to the auxiliary tank. Additional air vent pip-ing may be required if the auxiliary expansiontank is not located directly above the engine-mounted expansion tank. Figure 7.25 shows therecommended method of adding expansion vol-ume to the cooling system.

The auxiliary tank should be supported sepa-rately and isolated with a flexible connector

against vibration from the engine-mounted tank.A pressure cap or vent cap is required. Auxiliarytank minimum volume should include total expan-sion volume required plus the water volume tothe low water level in the tank. Figure 7.26,Auxiliary Expansion Tank Sizing, can be used todetermine minimum volume required.

Table of Cooling System Volumetric Data

Figure 7.24

Cooling System Volumetric DataColumn A Column B

Allowable External Volume Engine Jacket Water System VolumeEngine With Engine Mounted Tank With Engine Mounted TankModel U.S. Gal Liters U.S. Gal Liters3116 0.0 0.0 7.5 28.03126 0.0 0.0 7.5 28.0

3304B 2.1 8.0 14.7 55.63306B 2.1 8.0 14.7 55.63176 0.0 0.0 12.0 45.03196 0.0 0.0 12.0 45.0

3406C 10.0 38.0 23.6 94.53406E 10.0 38.0 23.6 94.53408C 14.0 53.0 37.5 142.03412 14.0 53.0 42.8 162.03508 64.0 243.0 75.3 285.03512 48.0 182.0 85.3 323.03516 32.0 122.0 101.4 384.0

Figure 7.25

109 LEBW1414-00

Auxiliary Expansion Tank Sizing, Engine Jacket WaterEngine Model ____________________ Rating ____________________ Hp at ___________________ rpm

1. Allowable external volume ___________ gal/L, with engine-mounted tank. (This value shownin Figure 7.24).

2. Total Volume of jacket water contained in external cooling circuit (not furnished as part ofengine) ___________ gal/L. See Figure 7.34, for volume per length of standard iron pipe.

3. Line 2 minus Line 1 ___________ gal/L.If this value is zero or less, additional tank is not required.If this value is greater than zero, an auxiliary tank is required.

4. If required, the minimum volume of the auxiliary expansion tank can be determined by:a. Engine volume, Figure 7.24, Column B ___________________________________________b. External volume Line 2 __________________________________________________________c. Multiply line a by 0.07 ___________________________________________________________d. Multiply line b by 0.05 ___________________________________________________________e. Total of lines c and d ____________________________________________________________(This is the minimum volume of the jacket water auxiliary expansion tank.)

For Separate Circuit Aftercooler:1. Total volume of aftercooler external water ___________ gal/L.2. Multiply Line 1 by 0.02 ___________ gal/L.3. Add the cold fill volume desired in auxiliary expansion tank to Line 2.

Total of Line 2 and cold fill volume ___________ gal/L.(This is the minimum volume of the aftercooler circuit auxiliary expansion tank.)

Figure 7.26

System ConsiderationsStrainers and Filters

Strainers are used with large fabricated coolantpiping systems to protect the cooling systemfrom physical damage due to circulating abra-sive materials and the plugging that occurs whenlarge foreign materials enter the system. Areashaving abundant marine life or shallow waterdrilling are benefited most by strainers.

Strainers should be installed as close to the hullas possible on the sea water inlet circuits.

Welded structural steel keel or skin cooler sys-tems need strainers installed between the coolerand pump inlet. Material, such as weld slag andcorrosion products, must be removed from thesystem to prevent wear of cooling system com-ponents.

Full-flow strainers of the duplex type are desir-able. Strainer screens should be sized no largerthan 0.125 in. (2.3 mm) mesh for use in sea watercircuits and 0.063 in. (1.6 mm) mesh for use in

closed fresh water circuits. Strainer connectionsshould be no smaller than the recommendedline size. A differential pressure gauge across theduplex strainers indicates pressure drop andenables the operator to determine when strainersneed servicing.

Pressure drop across a strainer at maximumwater flow should be considered as part of thesystem’s external resistance. Suppliers can helpin proper selection of strainers and furnish thevalues of pressure drop versus flow rate. Thestrainer selected should impose no more than3 ft. (1 m) water restriction to flow under cleanstrainer conditions.

Careful initial cleaning of the fabricated coolingsystem in addition to annual cleaning will keepaccumulation of wear-causing debris to a mini-mum. Maintenance of proper water coolantinhibitor concentrations will aid in minimizingformation of debris.

Some form of continuous bypass filter shouldalso be used to remove smaller particles and

LEBW1414-00 110

sediment. Element size of the continuous bypassfilter should be 20 to 50 microns.

Water flow through the bypass and filter shouldnot exceed 5 gal per min (19 L per min).

No filtering system is required on the enginejacket water circuit when the heat exchanger ismounted on the oilfield base.

Marine Growth

Marine growth in sea water cooling systemsoccurs in many areas of the world. Increasedtemperature and flowing food source are primarycauses. Experience is the best guide in knowingwhere marine growth is excessive.

Marine growth refers to minute marine plant oranimal life which enters the sea water coolingsystem, attaches itself, and grows. Sea waterstrainers have minimal effectiveness due to theminute size of the adolescent plant or animal life.(Strainers are effective with more mature plantor animal life.)

Marine growth can be controlled with varyingdegrees of success by several methods.

Periodic mechanical cleaning of heat exchanger,etc., removes accumulated growth. It may be nec-essary to clean sea water headers also.

Periodic chemical treatment combats marinegrowth. Chemical type and concentration mustbe controlled to prevent deterioration of the seawater cooling system components. Contact aknowledgeable chemical supplier.

Continuous low-concentration chemical treat-ment via either bulk chemical or self-generatingprocesses are offered by various manufacturers.

Coolant Velocity

Coolant flow in the system must be maintainedin a velocity range to achieve optimum heattransfer without erosion damage to system com-ponents. Jacket water external circuit velocitiesbetween 2 to 8 ft. per sec (0.6 to 2.5 m per sec) areacceptable. Sea water circuit velocities between2 to 6 ft. per sec (0.6 to 1.9 m per sec) are accept-able. Experience has shown these velocity rangesprovide required cooling and adequate system life.

Coolant velocities can be varied for a knownpump flow by increasing or decreasing the sizeof the pipe and components in the system. TMIor Engine Performance book lists flow values ofengine driven pumps. Figures 7.27 and 7.28 areuseful graphs for converting water flow to veloc-ity for pipes and tubes.

When electric sea water supply pumps are used, itis recommended that flow be adjusted for individ-ual engines with a balancing cock or glove valveon the supply side of each engine. Pressure gaugeson supply and return lines should be installed asa means of monitoring system operation.

System Pressure and Pressure Drop

Piping and heat transfer equipment resist cool-ing water flow, causing an external pressure headwhich opposes the water pump output. Coolingwater flow is reduced as external head increases.Total system resistance to flow must be limited toensure adequate flow. Resistance to flow is deter-mined by size and length of pipe, number andtype of fittings and valves used, coolant flow rate,and losses contributed by heat transfer devices.Excessive external heads demand pumps withadditional pressure capacity.

Depending upon arrangement, sea water differ-ential pressure at the engine heat exchanger canbe between 3 psi (21 kPa) and 12 psi (83 kPa).

Relief valves are required where sea water systemvalve sequencing could result in system over-pressures. Pressure control valves are requiredwhere sea water flow to engines could be acci-dentally diverted to ballast pumps, mud tanks, etc.

Check valves are not required on outlet of heatexchangers discharging into a common dis-charge manifold. Recirculation between heatexchangers does not occur.

A low sea water pressure alarm should be used incase sea water pumps are inadvertently turned offor to warn of gas entrainment of sea water pumpsduring an attempted blowout.

Total system resistance to flow must be limited toensure adequate flow. Resistance to flow is deter-mined by size and quantity of pipe, fittings, andother components in the cooling system. Asresistance (pressure drop) increases, water pumpflow decreases.

111 LEBW1414-00

External resistance imposed on the pump (alsocalled external head) includes both the resist-ance downstream of the pump outlet connectionand resistance ahead of the pump inlet. Resist-ance to flow in the external circuit of a closed cir-culating system consists only of the frictionalpressure drop.

Curves showing water flow versus external sys-tem head for engine jacket water pumps areavailable in the TMI. Maximum external resistancemust not be exceeded in the cooling circuit addedby the customer in order to maintain minimumwater flow. Flows lower than the minimums shownin TMI or Engine Performance book for eachpump circuit will shorten the life of the engine.

VELOCITY VS FLOWStandard Pipe Sizes 1.5 to 5 in. (38.1 to 127 mm)

Figure 7.27

VELOCITY VS FLOWTube Sizes from 1 in. to 5 in. O.D. (25.4 mm to 127 mm)

(Common Usage Wall Thickness)Figure 7.28

50 100 150 200 250 300 350 400 450 gpm

282624222018161412108642 L/s

0

2

4

6

8

10

12

fpsm/s

3.5

3

2.5

2

1.5

1

.5

1.00 in. (25.4 mm)

1.50 in. (38.1 mm)

2.00 in. (50.5 mm)

2.25 in. (57.0 mm)

2.50 in. (63.5 mm)

2.75 in. (70.0 mm)

3.25 in. (83.0 mm)

3.50 in. (89 mm)

2.75 in. (95.3 mm)

4.00 in. (102.0 mm)

4.75 in. (121.0 mm)

5.00 in. (127.0 mm)

4.75 in. (121.0 mm)

1.25 in. (31.8 mm)

1.75 in. (41.8 mm)

2.12 in. (53.3 mm)

2.38 in. (60.0 mm)

V = Vel (tps)Q = Flow (gpm)A = in2 (ID)ID = Inside Dia.

For Other WallThicknesses

V = 0.321 Q

= 0.408 Q

A ID2

Nom. Tube Size 0.65 in. (1.65 mm) Wall

FLOW

VE

LO

CIT

Y

50 100 150 200 250 300 350 400 450 gpm

282624222018161412108642 L/s

0

2

4

6

8

10

12

fpsm/s

3.5

3

2.5

2

1.5

1

.5

1.50 in. (38.1 mm)

2.00 in. (50.8 mm)

2.50 in. (63.5 mm)

3.00 in. (76.2 mm)

3.50 in. (89.0 mm)

4.00 in. (102.0 mm)

4.50 in. (114.0 mm)

5.00 in. (127.0 mm)

FLOW

VE

LO

CIT

Y

LEBW1414-00 112

Typical Friction Losses of Water In Pipe(Old Pipe) (Nominal Pipe Diameter)

Figure 7.29

Gallons GallonsPer Head Loss in Feet Per 100 Ft Per

Minute (m per 100 m) Minute3/4" 1-1/4" 1-1/2" 2-1/2"

gpm L/s (19.05 mm) 1" (25.4 mm) (31.75 mm) (38.1 mm) 2" (50.8 mm) (63.5 mm) gpm L/s5 0.34 10.5 3.25 0.84 0.40 0.16 0.05 3" (76.2 mm) 5 0.34

10 0.63 38.0 11.7 3.05 1.43 0.50 0.17 0.07 10 0.6315 0.95 80.0 25.0 6.50 3.05 1.07 0.37 0.15 15 0.9520 1.26 136.0 42.0 11.1 5.20 1.82 0.61 0.25 20 1.2625 1.58 4" (101.6 mm) 64.0 16.6 7.85 2.73 0.92 0.38 25 1.5830 1.9 0.13 89.0 23.0 11.0 3.84 1.29 0.54 30 1.935 2.21 0.17 119.0 31.2 14.7 5.10 1.72 0.71 35 2.2140 2.52 0.22 152.0 40.0 18.8 6.60 2.20 0.91 40 2.5245 2.84 0.28 5" (127 mm) 50.0 23.2 8.20 2.76 1.16 45 2.8450 3.15 0.34 0.11 60.0 28.4 9.90 3.32 1.38 50 3.1560 3.79 0.47 0.16 85.0 39.6 13.9 4.65 1.92 60 3.7970 4.42 0.63 0.21 113.0 53.0 18.4 6.20 2.57 70 4.4275 4.73 0.72 0.24 129.0 60.0 20.9 7.05 2.93 75 4.7380 5.05 0.81 0.27 145.0 68.0 23.7 7.90 3.28 80 5.0590 5.68 1.00 0.34 6" (152.4 mm) 84.0 29.4 9.80 4.08 90 5.68

100 6.31 1.22 0.41 0.17 102.0 35.8 12.0 4.96 100 6.31125 7.89 1.85 0.63 0.26 7" (177.8 mm) 54.0 17.6 7.55 125 7.89150 9.46 2.60 0.87 0.36 0.17 76.0 25.7 10.5 150 9.46175 11.05 3.44 1.16 0.48 0.22 8" (203.2 mm) 34.0 14.1 175 11.05200 12.62 4.40 1.48 0.61 0.28 0.15 43.1 17.8 200 12.62225 14.20 5.45 1.85 0.77 0.35 0.19 54.3 22.3 225 14.20250 15.77 6.70 2.25 0.94 0.43 0.24 65.5 27.1 250 15.77275 17.35 7.95 2.70 1.10 0.51 0.27 9" (228.6 mm) 32.3 275 17.35300 18.93 9.30 3.14 1.30 0.60 0.32 0.18 38.0 300 18.93325 20.5 10.8 3.65 1.51 0.68 0.37 0.21 44.1 325 20.5350 22.08 12.4 4.19 1.70 0.77 0.43 0.24 50.5 350 22.08375 23.66 14.2 4.80 1.95 0.89 0.48 0.28 10" (254 mm) 375 23.66400 25.24 16.0 5.40 2.20 1.01 0.55 0.31 0.19 400 25.24425 26.81 17.9 6.10 2.47 1.14 0.61 0.35 0.21 425 26.81450 28.39 19.8 6.70 2.74 1.26 0.68 0.38 0.23 450 28.39475 29.97 7.40 2.82 1.46 0.75 0.42 0.26 475 29.97500 31.55 8.10 2.90 1.54 0.82 0.46 0.28 500 31.55750 47.32 7.09 3.23 1.76 0.98 0.59 750 47.32

1000 63.09 12.0 5.59 2.97 1.67 1.23 1000 63.091250 78.86 8.39 4.48 2.55 1.51 1250 78.861500 94.64 12" (305 mm) 11.7 6.24 3.52 2.13 1500 94.641750 110.41 1.1 7.45 4.70 2.80 1750 110.412000 126.18 1.4 10.71 6.02 3.59 2000 126.182500 157.73 1.8 2500 157.73000 189.27 2.5 3000 189.3

When designing engine cooling systems, pres-sure drop (resistance) in the external coolingsystem can be calculated by totaling the pres-sure drop in each of the system’s components.Figures 7.29 and 7.30 can be used to determinepressure drop through pipe, fittings, and valves.Suppliers of other components, such as strain-ers and sea cocks, can provide required data ontheir products.

It is always necessary to evaluate the design andinstallation of cooling circuits by testing the oper-ation and effectiveness of the completed systemto ensure proper performance and life.

113 LEBW1414-00

Figure 7.30

Resistance of Valves and Fittingsto Flow of Fluids

EXAMPLE: The dotted line shows thatthe resistance of a 6-inch StandardElbow is equivalent to approximately16 ft. of a 6-inch Standard Pipe.

NOTE: For sudden enlargements orsudden contractions, use the smallerdiameter, d, on the pipe size scale.

LEBW1414-00 114

Emergency Radiator CircuitsSome offshore drilling contractors may desire toinstall a radiator on one drill rig engine in orderto supply some power whenever the sea watersystem becomes inoperative, Figure 7.31.

The radiator core must be suitable for 30 psi(206 kPa) operation due to the controlled inlettemperature regulators. The radiator core oper-ates near the engine jacket water pump pressureplus radiator cap pressure setting. See the sec-tion Water Temperature Regulators for additionalinformation.

The radiator should have an expansion tank tocollect any entrained gas. The pressure capshould be removed and replaced with a 3/8 in.(10 mm) vent line to the engine-mounted expan-sion tank. A 1/4 in. (8 mm) orifice should beinstalled to limit flow. If more than one engineis connected to this radiator, each engine musthave a vent line with a shutoff valve to be closedwhen the engine is not running. See the sectionRadiators with Expansion Tanks for additionalvent line information.

See the section Watermaker Installation Require-ments for proper circuit requirements. Figure 7.15is the proper circuit.

RadiatorsRadiator cooling is the most common type ofclosed cooling systems. Radiator cooling pro-vides a closed, self-contained system that is bothsimple and practical for most installations.

Cooling of the engine parts is accomplished bykeeping the coolant circulating and in contactwith the metal surfaces to be cooled. The pumpdraws the coolant from the bottom of the radia-tor, forces it through the jackets and passages,and ejects it into a tank on top of the radiator.The coolant passes through a set of tubes to thebottom of the radiator and again is circulatedthrough the engine by pump action. A fan drawsair over the outside of the tubes in the radiatorand cools the coolant as it flows downward. Itshould be noted that the coolant is pumpedthrough the radiator from the top down.

Figure 7.31

115 LEBW1414-00

The top tank is used for filling, expansion, anddeaeration of engine coolant. Extended systemsusing added coolant may require enlarged toptanks. The top tank is fitted with a pressure cap.This cap allows coolant level to be checked andreplenished as necessary. The cap also seals thecooling system and limits its pressure with aspring loaded disc valve.

The cooling system is designed to operate undera pressure of 4 to 7 psi (27.6 to 48.3 kPa) whichresults in a top tank temperature of 210°F (99°C).This limit minimizes water pump cavitation andprevents steam formation in the engine waterjacket. For each 1 psi (6.9 kPa) of pressure, theboiling point is raised about 3°F (2°C).

The radiator fan represents a parasitic load of about1.5% to 8% of the engine gross power output.

Information on attachment radiator fan groups isavailable in the TMI.

A selection of radiators with engine-driven fans isavailable for each Caterpillar Engine model. Theseradiators are fin and tube type and are generallyavailable in two sizes for each engine; the smallerdesigned for 110°F (43°C) maximum ambient,and the larger for 125°F (52°C) maximum ambi-ent. 140°F (60°C) are available for some con-figurations. Specific values can be supplied, asambient capability will vary with engine power.

PerformanceRadiator Design Criteria and Considerations

The following factors must be considered whendesigning and installing a radiator cooling system.

• Size the radiator to accommodate a heatrejection rate approximately 10% greaterthan the engine’s heat rejection. The additional10% will compensate for possible variationsfrom published or calculated heat rejectionrates, overload, and system deterioration.Even if the expected load is less than theengine rated power, size the radiator to matchengine rated power.

• Correction factors to the observed ambientair temperature capability for the enginemust not be overlooked. Altitude above sealevel reduces the density of air and its abilityto cool the radiator. A good correction fac-tor is 2°F (1.38°C) deducted from theobserved ambient temperature capability foreach 1000 ft. (305 m) above sea level.

• Ambient air temperature may not be thesame as the air temperature flowing acrossthe radiator core. An engine equipped withan engine-mounted radiator and blower fanwill increase the air temperature as it flowsacross the engine to the radiator. The ambi-ent temperature rise for different radiatorlocations is found in Figure 7.32.

Figure 7.32. Estimated air to core rise.

• The effects of antifreeze must be consideredwhen sizing a radiator. The ability to transferheat diminishes when water is mixed withethylene glycol. The loss in ambient capa-bility due to antifreeze is about 1.8°F (1°C)for each 10% glycol, up to 50%.

• Fan noise should be considered when select-ing radiator location. Fan noise transmitsthrough the air inlet as well as the outlet. Softflexible joints between the radiator and theducting will minimize vibration and noisetransmission.

• Position the radiator so prevailing winds donot act against the fan. One form of wind pro-tection for radiators is a baffle located sev-eral feet from the radiator air discharge.Another method is to install an air duct out-side the wall and mounting the air inlet oroutlet vertically. Large radius bends and turn-ing vanes prevent turbulence and excessiveair flow restriction.

• Backpressure or air flow restriction reducesradiator performance. If radiator air flow is tobe ducted, consult TMI or your radiator man-ufacturer regarding the allowable backpres-sure. An engine installation in an enclosedspace requires that the inlet air flow rate tothe enclosed space include the combustionair requirements of the engine, unless the airfor the engine is ducted directly to the enginefrom the outside.

Blower SuctionFan Fan

Engine only, outside or 5.4°F Nonein a large engine room (3°C)Engine/generator outside 7.2°F Notor in a large engine room (4°C) Recommended

with generatorEngine/generator in enclosure 12.6°F with external muffler (7°C)Engine/generator in enclosure 16.2°Fwith internal uninsulated muffler (9°C)

LEBW1414-00 116

• Air flow losses and EfficiencyParticular attention should be given to itemsrestricting air flow, both in front of the radia-tor and to the rear of the fan. The additiveeffects of guards, bumpers, grills, and shut-ters in front of the radiator, pulleys, idlers,engine-mounted accessories, and the engineitself behind the fan can drastically reduceair flow.

Fan Drives

Caterpillar fan drives are designed to prevent exces-sive crankshaft loading and to resist vibrations.

Fan drives sometimes require an outboard bear-ing on the crankshaft pulley. These drives musthave a flexible coupling between the pulley andthe engine crankshaft. This coupling must notinterfere with the longitudinal thermal growth ofthe crankshaft.

CAUTION: Fan belt and drive guard may not befactory supplied due to the large number of pos-sible configurations which we cannot identify.OSHA and other government bodies may haveregulations concerning this. The user is respon-sible to provide such guards where required butnot factory supplied.

Figure 7.33

Figure 7.34

Pipe DimensionsStandard Iron Pipe

Nominal Size Actual I.D. Actual O.D. ft per m per ft per m perIn (mm) In (mm) In (mm) gal. Liter cu. ft. m 3

1/8 3.18 0.270 6.86 0.405 10.29 336.000 27.000 2513.000 27,049.01/4 6.35 0.364 9.25 0.540 13.72 185.000 16.100 1383.000 14,886.03/8 9.53 0.494 12.55 0.675 17.15 100.400 8.300 751.000 8083.01/2 12.70 0.623 15.82 0.840 21.34 63.100 5.000 472.000 5080.03/4 19.05 0.824 20.93 1.050 26.68 36.100 2.900 271.000 2917.0

1 25.40 1.048 26.62 1.315 33.40 22.300 1.900 166.800 1795.01-1/4 31.75 1.380 35.05 1.660 42.16 12.850 1.030 96.100 1034.01-1/2 38.10 1.610 40.89 1.900 48.26 9.440 .760 70.600 760.02 50.80 2.067 52.25 2.375 60.33 5.730 .460 42.900 462.02-1/2 63.50 2.468 62.69 2.875 73.02 4.020 .320 30.100 324.03 76.20 3.067 77.90 3.550 88.90 2.600 .210 19.500 210.03-1/2 88.90 3.548 90.12 4.000 101.60 1.940 .160 14.510 156.04 101.60 4.026 102.26 4.500 114.30 1.510 .120 11.300 122.04-1/2 114.30 4.508 114.5 5.000 127.00 1.205 .097 9.010 97.05 127.00 5.045 128.14 5.563 141.30 0.961 .077 7.190 77.06 152.40 6.065 154.00 6.625 168.28 0.666 .054 4.980 54.07 177.80 7.023 178.38 7.625 193.66 0.496 .040 3.710 40.08 203.20 7.982 202.74 8.625 219.08 0.384 .031 2.870 31.09 228.60 8.937 227.00 9.625 244.48 0.307 .025 2.300 25.0

10 254.00 10.019 254.50 10.750 273.05 0.244 .020 1.825 19.612 304.80 12.000 304.80 12.750 323.85 0.204 .016 1.526 16.4

117 LEBW1414-00

Radiator Installation CriteriaPiping

Coolant connections must be as large as (or largerthan) applicable engine coolant connections.

Outlet piping to the radiator must have a contin-uous upward slope. Low spots will cause engineto be an air trap to combustion gas leakage,Figures 7.11, 7.13 and 7.43.

In order to maintain the correct flow relationshipin the radiator top tank, it is recommended thatno lines tee into the vent lines.

Offset Radiator

Where compound spacing causes radiator inter-ference, it is possible to offset radiators to gainclearance. This is most successful where the radi-ator fan is radiator mounted.

Crankcase Breathers

Crankcase breather fumes should be ductedaway from the radiator core when blower fans areused. See the section on Crankcase Ventilationfor further information.

Miscellaneous

Guards should be fabricated for all exposed belts,pulleys, or fans.

Radiator Mounting on Mobile EquipmentSeveral of the 3408/3412 radiators require abase when engine-mounted, Figure 7.35. Thebottom of these radiators is lower than the engine.The base raises the engine. In such cases, engineheight may become unacceptable. For example,the derrick may no longer lay down.

Figure 7.36 illustrates the base has not been usedand radiator is supported off the carrier frame.Determine that upper radiator connections donot interfere with derrick.

Many times in-line engine configurations willmount between the carrier’s frame members. Theradiator usually will not fit. Optional mobile fandrives can then be used to provide a high mountfan drive up to the limits of their adjustments. Thecustomer will have to supply the radiator or atleast fabricate new water lines and supports.

Figure 7.35

Figure 7.36

LEBW1414-00 118

Figure 7.37

The radiator top braces on radiators 17.0 ft2

(1.6 m2) and larger may not be adequate torestrain the radiator during off-road travel. Thiswould be particularly true with cross-mountedengines. For this reason, a sturdy brace is requiredbetween the radiator top tank and rig structure,Figure 7.37. Brace angle should not be shallowerthan that for the existing brace (which is to bediscarded). This bracing recommendation is anengine installation requirement to be met byengine installer.

Additionally, service units require the radiator bot-tom supports to be securely connected to the rig.This protects against the large side-to-side chas-sis movements caused by the triplex pump. Theradiator top may require side bracing as the radi-ator shock mounts allow large top end movement.

Piping between the engine and the radiator shouldbe flexible enough to provide for relative motionbetween the two. Hoses less than 6 in. (15.24 cm)in length provide little flexibility and are difficultto install. If the hose is more than 18 in. (45.7 cm)in length, it is susceptible to failure from vibrationor coming loose at the connections. Long hoseson the inlet require wire support on the insidediameter to prevent collapsing. Support the pip-ing with brackets, when necessary, to take weightoff a vertical joint. High quality hose, clamps andfittings are a prerequisite for long life and to avoidpremature failure. It if also necessary to bead pipeends to reduce the possibility of a hose blowing

off. Double clamps are desirable for all hose con-nections under pressure.

Radiator ambient capacity will be reduced bythings such as: fan air recirculation due to vehiclecab, oil-to-air coolers added to core, watercooledexhaust manifolds, torque converter coolers, etc.

Radiator Structure

Caterpillar industrial radiators such as the 3300Series unit construction type and the 3400 Seriesbolted core are not designed for applications withextreme machine vibration and large impactloads. The maximum total amplitude of vibrationallowed at any point on the radiator core is 10 mil(±5 mil). Core isolation is provided by rubbermounts from the radiator frame sufficient to limitcore vibration amplitude for relatively high fre-quency vibration; but low frequency vibration inthe order of 15 Hz may amplify radiator coremotion beyond 10 mil. In these cases specialmachine frame or radiator support modificationsmust be made.

Radiator Performance Criteria

Since many of the radiators used by equipmentmanufacturers will not be Caterpillar designed, acomplete evaluation of the cooling system isrequired to prove the capability of the system.

Caterpillar Application Engineering can providespecific information on methods and criteria usedto evaluate radiator performance criteria or referto EDS 50.5, Form LEKQ3296. A cooling systemtest needs to be performed in accordance withEDS 50.5 when a Cat radiator or expansion tankis NOT used.

Additional Heat Load

Frequently, the engine cooling system is utilizedto cool additional systems, such as transmissionsand torque converters. The heat rejection of thesedevices must be considered when sizing the radi-ator. The additional heat load which must beadded is 30% of flywheel power multiplied by42.4 Btu/min/hp. (0.74 watt/hr/kW) on enginesdriving mud pumps. Use a factor of 20% of fly-wheel power for torque converters built into trans-missions.

Because the torque converter oil cooler is on thepressure side of the engine water pump, pres-sure rated hose should be used and anchored

119 LEBW1414-00

securely. See Figure 7.39. Hose clamps are inad-equate to anchor securely. The cooler devicemust not present undue restriction to enginecoolant flow.

Figure 7.38 lists the cooler or cooler connectionsavailable on oilfield engines. The btu/min heatrejection capacity may vary if other than SAE30W oil is used.

Water lines to the cooler must be high quality andanchored to the engine so that hose failures dueto rubbing cannot occur.

Figure 7.39

Cold Fill and Low Coolant Level Marks

Caterpillar recommends a cold fill mark be notedon the expansion tank or surge tank, Figure 7.40.This indicates to the operator when the coolingsystem is full.

The radiator should contain a low coolant levelmark, Figure 7.40. It should be at or above thecoolant level established under the coolant levelheading. This mark should be based on a coldwater condition.

Coolant Level

Caterpillar recommends a water reserve of 2 gal-lons (7.57 L) or 12% of system capacity, which-ever is greater, be provided. In systems wheretotal coolant capacity is more than twice enginecapacity, a reserve of 5% is sufficient.

Radiators With Expansion Tanks

Commercially available radiators may use expan-sion tanks instead of top tanks. Such a radiatormust also meet the criteria listed in this section,Figure 7.41, and the section on Remote-MountedRadiators.

Expansion and Afterboil Volume

An expansion volume equal to 10% of systemcapacity must be provided to accommodate cool-ant expansion and afterboil occurring at engineshutdown. Failure to allow for this can result incoolant overflow, dilution of antifreeze by subse-quent makeup coolant, and possible water pumpcavitation caused by reduction in coolant level.In systems where total capacity is more than twiceengine coolant capacity, an expansion volumeof 8% can be used, Figures 7.40 and 7.41.

TORQUE CONVERTER CONNECTIONS

Figure 7.38

Auxiliary Cooling Provisions3516 3512 3508 3412 3412 3408 3406 3306 3304

(1200) (1200) (1200) (1200) (1800) (1800)Connections Only

gpm (L/s) 125 100 75 200 215 165 100(7.9) (6.31) (4.7) (12.7) (13.6) (10) (6.3)

psi (kPa) (water) 5 5.6 6.7 10 10 10 10(34.5) (38.6) (46.2) (69) (69) (69) (69) (69)

Cooler OnlyOil gpm (L/s) 70 70 37 40 16 20

(4.41) (4.41) (2.33) (2.52) (1.01) (1.26)Oil psi (kPa) 75 75 75 75 75 75

(517.1) (517.1) (517.1) (517.1) (517.1) (517.1)psi (kPa) 20 20 16.4 20 20 15(oil pressure drop) (137.9) (137.9) (113) (137.9) (137.9) (103.4)

Heat Rejection 9558 9558 5688 3750 2225 900btu/min (kW) (170) (170) (101) (67) (39) (16)(SAE 30W Oil)

LEBW1414-00 120

Radiator Overfilling

A radiator “brim-full” will expel water through theoverflow when the engine is started and broughtup to operating temperature. If the radiator isrefilled to brim-full when it is shut down, waterwill again be expelled when the engine is started.

Continued operation under this cycling will resultin diluting the cooling system anti-freeze and cor-rosion protection.

Additionally, makeup water may be poor qualityand cause harmful deposits.

Operating personnel should be instructed toNOT fill radiators brim-full, but up to the coldfill mark only.

Air/Gas Venting

Combustion gas leakage and entrained air must bevented from the cooling liquid. The ventingrequirement for each engine is shown in EDS 50.5.Separation of gas from a liquid medium requiresa low coolant velocity at the top of the radiatorand a relatively quiescent flow. Coolant velocityacross the top of a radiator core should beapproximately 2 fps (9.4 cm/s). Another way ofstating this limit is based on the rate of change ofthe fluid volume above the core. The maximumrate of change of volume should be 200 changesper minute. For example, if the volume of waterabove the core is 1 gal and the engine coolant

flow rate is 110 gpm, the 1 gal volume would bechanged 110 times per minute.

Any entrained air present in the external systemis also drawn into the water pump, causing cav-itation. Cavitation can also be caused by under-sized piping creating a vacuum at the water pumpinlet, causing water to boil. A cavitating pumpreduces the amount of water being circulated,usually resulting in engine damage.

Water Pump Cavitation

Given proper conditions of pressure and tem-perature, all liquids will form a gaseous state(boiling point). In the cooling system pump inlet,a gas or vapor bubble will displace liquid andreduce the amount of liquid that can be pumped.This loss of pumping volume can be observed asa loss in water pump pressure rise. The maxi-mum pump rise loss acceptable at the cavitationtemperature is 10% of the pressure rise observedat 120°F (48°C) coolant temperature to the pumpwhile operating at rated speed. Acceptable cav-itation temperature for a given engine is 210°F(98°C) minus the temperature rise across theengine when fully loaded. EDS 50.5 shows amethod for calculating temperature rise. As ageneral rule, temperature rise will be in the rangeof 10°F to 18°F (5.5°C to 10°C). The TMI pro-vides heat rejection to jacket water and pumpflow which allows temperature rise calculations.

RADIATOR TOP TANK REQUIREMENTS

Figure 7.40

121 LEBW1414-00

Cavitation characteristics observed during anevaluation can be affected by system air ventingcapability. If air venting problems are present,cavitation temperature should be rechecked aftera solution to the venting problem is found.

Cooling Level Sensitivity (Drawdown)

Drawdown capability from full coolant level with180°F (82°C) pump inlet temperature and engineoperating at rated speed must be 12% of the totalsystem volume with no more than a 10% loss inpump pressure rise. This level, so established, isthe low level reference position and should bemarked in such a manner on the radiator toptank that it can be accurately detected by visualinspection. A metal plate or sight glass shouldbe provided. The 12% value is appropriate fora system which uses a 7 psi pressure cap, butlower pressure systems should provide 16%drawdown capability.

Duct Work

Duct work and adjustable shutters can be used todirect some or all of the warmed radiator air forheating purposes. If this air is used to heat the

engine room, engine room temperature shouldbe below 75°F (24°C).

Duct work should be supported independent ofengine or radiator.

Static pressure imposed by duct work must bedetermined for each installation. The radiatormanufacturer should be consulted to determinepermissible static pressure.

Radiator Air Flow

Backpressure or air flow restriction reduces radi-ator performance. If radiator air flow is to beducted, consult the radiator manufacturer regard-ing allowable backpressure. An engine installationin an enclosed space requires that the inlet air vol-ume include engine combustion air requirements.

Remote-Mounted Radiators

Remote systems impose added restriction oncooling water flow by additional piping and fit-tings. An auxiliary pump in series with the engine-mounted pump should not be used to overcomethis restriction. Consideration should be given toradiator design and larger piping.

Figure 7.41

LEBW1414-00 122

TMI contains performance curves of variousjacket water pumps. Refer to Figures 7.27, 7.28,7.29 and 7.30 for information on water velocityversus flow, frictional losses of water in pipe, andresistance of valves and fittings to flow of fluids.

Remote-mounted radiators should never belocated more than 57 ft. (17.5 m) above theengine. At greater heights, the static head devel-oped may cause leakage of the engine waterpump seals.

The radiator top tank loses its air venting capa-bility if it is located below the level of the engineregulator housing. When a radiator must bemounted lower than the engine, the factory sup-plied expansion tank must be used, Figure 7.42.

Radiator design operating pressure must beincreased by 1 psi (6.9 kPa) for every 2 ft.(610 mm) the engine is above the radiator. Radia-tor pressure caps should not be used. It should beremoved and the opening sealed. For best oper-ation, water flow through the radiator should bereversed. This ensures gas or air does not gettrapped in the radiator top tank, Figure 7.42.

Remote radiators may also be on the same levelas the engine, Figure 7.43.

Oversize piping may be required to minimize pip-ing loss.

As shown in Figure 7.43, do not run the enginewater outlet line below the engine. Such designdoes not allow the engine to vent air or combus-tion gas to the radiator. Vent plugs could vent forinitial fill, but combustion gas produced duringoperation would accumulate in the engine cool-ing system and cause severe engine damage.

Radiators for use with expansion tanks mustwithstand a water operating pressure of 30 psi(207 kPa). (Caterpillar radiators are not recom-mended for this pressure.) This higher tubepressure results because the thermostats in anexpansion tank circuit are changed to a controlledinlet configuration. See the section on WaterTemperature Regulators. Conventional radiatortubes may flex and leak due to this pressure.

Figure 7.42

Figure 7.43

123 LEBW1414-00

WATER HEATER

Figure 7.44

Jacket Water HeatersJacket water heaters should be considered forfaster, easier starting in ambient air temperaturesbelow 70°F (21°C). All automatic installations,standby generators, etc., should include theseheaters, Figure 7.44.

JACKET WATER HEATER SIZES(Minimum Ambient Room Temperatures °F/°C,

No Wind and 10 hour warmup to 90°F/33°C)

Figure 7.45

Figure 7.45 indicates the correct size heater foreach engine model at minimum ambient roomtemperatures to maintain engine jacket waterat approximately 90°F (32°C). Heater sizingis based on wind velocity around the engine of0 mph (0 kmh).

When a 15 mph (24 kmh) wind is present, heaterrequirement doubles.

Time required for temperature to stabilize is10 hours. Wattage requirements for shorter timeperiods are inversely proportional to the 10-hourrequirements.

These heaters do not require circulating pumps.Physical location and exposure to wind can affectsizing.

Contact Caterpillar for special voltages, three-phase current, and special heaters for ambienttemperatures lower than those listed.

For those who install their own systems, thesesuggestions should be noted.

1. Mount heater as low as possible.

2. Cold water inlet to heater should be fromlowest possible point in the engine coolingsystem.

3. Avoid cold water loops — any situation wherecold water must rise to enter the heater.

4. Join hot water side of heater near top ofengine cooling system, but below the ther-mostats. CAUTION: DO NOT CREATE HOTWATER LOOPS. Hot water line should enterengine in either a horizontal or slightlyinclined plane, eliminating the possibility offorming a steam pocket.

5. Use same pipe size (or larger) as heaterconnections.

Cold Weather ConsiderationsForm SEBU5338-01 Cold Weather Operation,contains information on operation, lubrication,and maintenance in cold weather conditions.

Methods of retaining engine heat are discussedbelow.

Commercially available radiator shutters shouldbe considered. Fan air flow across the engineincreases heat lost to radiation. Particularly atlight load, shutters minimize this heat loss andraises the engine temperature.

kW required Engine Attachment Units to achieveModel 3.0 kW 2 2 3.0 kW –40°F/–40°C3516 –10/–23 9 kW3512 –30/–34 7.5 kW3508 –40/–40 5.5 kW3412 –40/–40 4.5 kW3408 –40/–40 3.5 kW3406 –40/–40 3 kW3306 –40/–40 1 kW3304 –40/–40 .75 kW

Commercially available diesel fuel fired jacketwater heaters should be considered on enginesthat must start when no AC power is available.

Engine enclosures or engine room enclosures arerecommended to retain engine heat.

Extreme Cold Weather Considerations

Extreme conditions require additional protection,Figure 7.46. This protection is commerciallyavailable.

The radiator should be in a separate room fromthe engine. Absence of the radiator air flow willensure the engine environment is kept at a warmertemperature in cold weather.

In warm temperatures, the weather enclosure iseither removed or opened. Radiator cooling airis drawn in through a roof door in the radiator roomduring winter operation. Normally, radiator dis-charge air is utilized for rig heating.

If emissions regulations allow them, two-speedradiator fans are recommended because theyoffer several advantages for utilization of engineheat. First, lower fan speed reduces air flow andconsequently increases air temperature rise of theradiator air flow utilized for rig heating. Second,radiator fan horsepower is considerably reduced.

Sensors for the two-speed motor and shuttershave to be protected from being affected by thecold air coming through the roof door. The roofdoor area is sized to accommodate only the

low fan speed air requirements. The opening isadjustable. The enclosure door will have to beopened by hand for summertime operation.

The house should be as airtight as possible. Thisincludes an air barrier under the engine oil pan,as illustrated.

To minimize air changes in the engine room,combustion air can be ducted to the air cleanerfrom outside, as shown. An air source valve isincluded so the engine can be started and idledon the warmer air in the engine room. The engineshould be operated on outside air. Otherwise, avacuum may be caused in the engine room,depending upon how airtight the engine roomis. Air cleaner adapters are available to connectducting.

Heavy duty air cleaners can be utilized for pro-tecting the engine from air cleaner plugging dueto “ice fogs,” if they occur.

Crankcase breather fumes should be piped out ofthe engine room to minimize oily deposits. Inextremely cold weather, the fumes may have tobe discharged into the engine room due tobreather outlet freezing. Fumes should be dis-charged as remotely as possible from engine aircleaner inlets. An alternative sometimes used isto discharge the fumes under the power modulebase where it is generally warmer.

Lube oil and jacket water heaters should be pro-vided. They are required for cold startup after a

LEBW1414-00 124

Figure 7.46

125 LEBW1414-00

rig move. (Power is supplied by a small cold startgenerator set.) They also can be used to main-tain the temperature of an engine that is not run-ning. On many rigs all engines are generally runat all times, as there is no reliable way to keep theengine ready for service at a moment’s notice,with a resultant increase in fuel usage. Jacketwater heaters are readily available, but oil heatersare not. Oil is difficult to heat without circulation.Thus, immersion-type oil heaters are generallynot recommended as they lead to coking of theoil. Unitized oil and water heaters are commer-cially available which overcome the problem.They employ oil and water circulating pumps forproper system operation.Exhaust piping should be so arranged that exhaustwill NOT be drawn into the radiator or combus-tion air inlet.

Sizing and Installing Radiators forEPA Certified 3500B Engines

Consult EPA document 40 CFR Part 89 for detailedinformation on EPA regulations. Caterpillar radi-ators meet these requirements.Radiators must be sized to properly cool both thejacket water and SCAC systems at maximumambient conditions and the conditions describedbelow to comply with the EPA regulation. Failureto do so may be considered tampering.Jacket water system sizing for EPA-certifiedengines remains the same as non-certifiedengines. The SCAC system, however, must beproperly sized to comply with EPA legislation.Specifically:SCAC radiator system must provide a maximumof 140°F (60°C) coolant to the aftercooler at140 gpm (530 L/min) minimum flow on an 86°F(30°C) ambient day. Ambient is defined as airtemperature outside of the engine room or build-ing in which it is installed.Unless air cleaners are ducted to air at ambienttemperature (inside or outside of the engine room),there will be an air temperature rise to the aircleaner. This rise will increase the intake manifoldtemperature and therefore affect emissions. Tocompensate for this air rise to the air cleaners (incases where ducting is not possible), SCAC watertemperature must be lowered by the amount ofair temperature rise above ambient in a 1:1 ratio.Caterpillar 3500B engine-mounted radiators aresized to allow for a 7°F (4°C) air rise to the inlet

face of the radiator core (ATC) without ductingthe air cleaners. Optional Caterpillar high ambi-ent radiators (122°F, 50°C) are available thatallow up to a 19°F (10°C) ATC rise where duct-ing is not practical.

For non-Caterpillar radiators or remote-mountedradiators, compensate for the air rise to the aircleaners by using the aforementioned 1:1 ratio.For example, if the temperature rise to the inletof the air cleaner is 10°F (6°C), the SCAC watertemperature to the aftercooler must be 140°F –10°F = 130°F at 86°F ambient (60°C – 6°C =54°C at 30°C ambient). Depending on the instal-lation, it may be more economical to duct the aircleaners to an ambient air location, or provide alarger SCAC radiator.

Consult EPA document 40 CFR Part 89 for properusage of auxiliary radiator control devices (suchas variable frequency drives, multi-speed motors,dampers etc.) to ensure they are in compliancewith the regulators.

Supplemental Radiator Design Criteria

Although Caterpillar-designed cooling packagesare recommended for many applications, thereare occasions where equipment manufacturersprefer to supply their own radiators. The follow-ing additional items should be considered withthese radiators.

Radiator Structure

Mobile equipment applications require radiatorconstruction which incorporates bolted top andbottom tanks with side channel support. Rein-forcing strips should be used on both sides of thecore header-to-tank bolted joint to limit distortion.Compressed rubber is often incorporated betweenthe core and the inboard side of the channelmembers to provide additional core support.

A complete evaluation of the cooling system isrequired to prove the capability of the system.Reference material for such an evaluation is pro-vided by Engine Data Sheet EDS 50.5. Anotheruseful reference for evaluating radiator top tankdesign is provided by EDS 52.1.

Cooling Capability

Caterpillar requires the maximum coolant dis-charge temperature to the radiator to be 210°F(98°C) for sea level operation and recommendsa minimum ambient capability of 110°F (42.9°C)

LEBW1414-00 126

during full load operation at all operating speeds.This includes all additional heat loads whichmight be imposed on the cooling system suchas torque converter coolers or air-to-oil coolerswhich might be added in front of the radiator.

As indicated in EDS 50.5, certain measuringdevices are required to evaluate cooling capa-bility. A suitable method for measuring enginepower could be a fuel meter, fuel setting indica-tor (rack position), or dynamometer. Additionalmeasured data are engine speed, jacket waterand aftercooler coolant temperatures in and outof radiator, air temperature to the radiator (sev-eral locations), and ambient air temperaturewhich is sampled far enough from the machineto eliminate effects of heat generated by theoperating machine.

Location of the test site should be such thatheated air which has passed through the radia-tor is not forced back through the radiator in anunrealistic manner by walls or other adjacentstructures (recirculation of air). Recirculation ofair can also be an inherent characteristic of thecooling system but should be avoided. Locatingnarrow strips of cloth on small pieces of wire fas-tened at various locations around the outside sur-face of the radiator provides an excellent flowpath indicator. Another useful tool for indicatingair flow path can be made by attaching a narrowstrip of cloth to the end of a long piece of wirewhich can be used as a probe around the engineor radiator periphery. Baffling of the radiator or airflow directors are often necessary to ensure thatunheated ambient air is directed to the radiatorfor most effective cooling. This is an insidiousproblem which should not be overlooked.

Cooling capability of a radiator and torque con-verter cooler are referenced to a 70% or 80% con-verter efficiency operating level as a general designconsideration. Normally, the performance char-acteristics of speed and torque ratio, input and out-put power, and the heat generated by lost poweris provided by the torque converter manufacturer.The efficiency characteristic will be associatedwith an engine speed, and cooling system oper-ating characteristics should be observed at thisengine speed whenever possible.

Equipment manufacturers often find that impos-ing a load on the engine is difficult to accom-plish during cooling test operations. Direct drivemachines are the most difficult and usually requirethat some type of dynamometer or other load

absorbing device be fastened to the output shaft.Torque converters can be used as load absorbingdevices if a separate cooling method (such ascold plant water) is provided to the cooler.Extended operation at converter stall can beaccomplished allowing all coolant temperaturesto stabilize without excessive torque converter oiltemperature. Note, however, that the coolingcapability established in this manner does notinclude the equivalent of 20% to 30% flywheelhorsepower which would normally be cooled bythe engine cooling system. This must be includedby calculation in the same manner as the calcu-lation shown in EDS 50.5 for extrapolatingobserved temperature data to 210°F (90°C) radi-ator top tank conditions. The additional heat loadwhich must be added is 20% to 30% of flywheelhorsepower multiplied times 42.4 Btu/min/hp.

Filling Ability (Reference EDS 50.5)

The cooling system must accept a bucket fillmethod (interrupted) and continuous fill methodat a minimum rate of 5 gpm (18.9 L/min) with-out air lock (false fill). The coolant should not bebelow the qualified low operating level afterengine start and warm-up. The low coolant levelis established during drawdown tests. False fill isa potential problem with all types of radiators.

Pump Cavitation (Reference EDS 50.5)

Verify capability in accordance with the earlier dis-cussion of water pump cavitation.

Cavitation characteristics observed during anevaluation can be affected by the system air vent-ing capability. If air venting problems are present,the cavitation temperature should be recheckedafter a solution to the venting problem is found.

Cooling Level Sensitivity (Drawdown)(Reference EDS 50.5)

Verify capability in accordance with the earlierdiscussion of cooling level sensitivity (Drawdown).

Air/Gas Venting (Reference EDS 50.5)

Verify capability in accordance with the earlierdiscussion of air/gas venting. See Figures 7.47,7.48, and 7.49 for suggested vent and fill pipingrouting.

127 LEBW1414-00

Other Radiator Considerations

Radiator inlet and outlet diameters should be thesame or, if possible, larger on the outlet and shouldbe located on diagonally opposite sides to limit“channeling” of coolant flow on one side of thecore. The bottom tank height of the radiatorshould be no less than the outlet tube diameter.

Radiator Core

Core frontal area should be as large as possibleto minimize restriction to air flow. Low radiatorcore restriction usually results in being able toprovide a larger diameter, quieter, slower turningfan, which demands less drive horsepower. Radi-ator cores which are nearly square can providethe most effective fan performance. They can beinstalled with a minimum of unswept core area.As a general rule, keep core thicknesses to aminimum with a maximum of 11 fins per inch.Increasing the number of fins per inch doesincrease the radiator heat rejection for a given airvelocity through the core but at the cost ofincreasing the resistance to airflow. While themost economical initial cost will be maximumcore thicknesses and fins per inch, this involveshigher fan horsepower with consequent operat-ing cost and noise penalties throughout the lifeof the installation. In addition, a radiator withmore fins per inch is much more susceptible toplugging from insects and debris.

Fan Recommendations

A. Fan Diameter and Speed

As a general rule, the most desirable fan isone having the largest diameter and turningat the lowest speed to deliver the required airflow. This also results in lower fan noise andlowest fan horsepower draw from the engine.Blade tip speed, while being only one ofthe elements of cooling fan design, is anitem easily changed with choice of fan drivepulley diameter. An optimum fan tip veloc-ity of 14,000 fpm (7112 cm/s) is a goodcompromise for meeting noise legislationrequirements and cooling system perform-ance requirements. Maximum acceptabletip speed is 16,000 fpm (9144 cm/s) forCaterpillar fans.

B. Fan Performance

Proper selection and placement of the fan iscritical to the efficiency of the cooling sys-tem. It requires careful matching of the fanand radiator by determining air flow neededand static air pressure which the fan mustovercome. This must be done since most dis-crepancies between cooling system calculatedperformance and test results are traceableto the “air side” and directly related to itemsaffecting fan air flow.

There are two major considerations for properfan selection:

1. Air flow needed to provide the requiredcooling.

2. Select a fan that provides the requiredair flow, and one that is relatively insen-sitive to small changes in static pressure.This desired design point is where asmall change in static pressure does notcause a large change in air flow. Select-ing a lower pressure point is not recom-mended as it could be in the unstable“stall” area where a small change in staticpressure causes a large change in airflow. Performance curves for availableCaterpillar fans are shown as air flow(cfm), static pressure head, (inches ofwater, gauge) and horsepower in theTMI. The Caterpillar curves are based onstandard air density, an efficient fanshroud, and no obstructions.

This is a theoretical air flow which is sel-dom possible because of some obstruc-tion. Theoretical air flow sometimes canbe approached with the fan in a properlydesigned close fitting shroud with nomore than 0.0625 in. (1.6 mm) blade tipclearance. Such a close fitting shroudis not practical, and tip clearance isincreased; a 0.5 in. (12.7 mm) clearanceis generally recommended. When a fanspeed different from those shown in thecurves is needed, the additional perfor-mance data can be calculated using thesefan rules:

For Speed Changes

cfm2 = cfm1rpm2_____rpm1

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Ps2 = Ps1 ( )2

hp2 = hp1 ( )3

For Diameter Changes

cfm2 = cfm1 ( )3

Ps2 = Ps1 ( )2

hp2 = hp1 ( )5

For Air Density Changes

Ps2 = Ps1

hp2 = hp1

Ambient Capability Adjustments(Air Flow or Fan rpm Changes)

∆T2 = ∆T1 ( )0.7

∆T2 = ∆T1 ( )0.7

Maximum Ambient Capability =210 – ∆T2

cfm = Air flow in cubic feet per minute.rpm = Fan speed in revolutions per minute.

Ps = Static pressure in inches of water.hp = Fan horsepower.

Dia = Fan diameter in inches.r = Air density in pounds per cubic foot.

∆T = Coolant top tank temperature minusambient air temperature.

C. Fan Shrouds and Fan Location

Two desirable types of shrouds are: venturiand box.

Maximum air flow and efficiency is providedby a tight fitting venturi shroud with sufficienttunnel length to provide straight air stream-lines. Small fan clearances require a fixedfan or an adjustable shroud. Although they

are somewhat less efficient than the venturishroud, box-type shrouds are most com-monly used because of lower cost. Properlypositioned, a simple orifice opening in thebox shroud is practical. Straight tunnelshrouds are usually less effective than ven-turi or box shrouds. The fan tip clearanceshould be 0.5 in. (12.7 mm) or less. A prop-erly designed shroud will:

1. Increase air flow.

2. Distribute air flow across core for moreefficient use of available area.

3. Prevent recirculation of air.

As a general rule, suction fans should be nocloser to the core than the projected bladewidth of the fan. Greater distance gives bet-ter performance. Consider also that engine-mounted items close to the back side of thefan can introduce vibrations into the fan tocause fan failure, increase fan noise, andreduce air flow. Suction fans should be posi-tioned so that two-thirds of the projectedwidth is inside a box shroud orifice platewhile a blower fan position is one-third insidethe shroud.

rpm1_____rpm2

cmf1_____cfm2

r2__r1

r2__r1

Dia2_____Dia1

Dia2_____Dia1

Dia2_____Dia1

rpm2_____rpm1

rpm2_____rpm1

129 LEBW1414-00

Proper Venting for Non-Standard Radiators

OUTLET CONTROLLED WITH VERTICAL RADIATOR COREFigure 7.47

OUTLET CONTROLLED WITH VERTICAL CROSS FLOW RADIATORFigure 7.48

OUTLET CONTROLLED WITH HORIZONTAL RADIATORFigure 7.49

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The lubricating system of a modern diesel engineaccomplishes three purposes. First, it lubricatesfriction surfaces to minimize friction losses.Second, it cools internal engine parts which can-not be directly cooled by the engine’s water cool-ing system. Third, it cleans the engine by flushingaway wear particles.

Proper lubrication requires clean oil free fromabrasive particles and corrosive compounds. Itrequires a lubricant with sufficient film strength towithstand bearing pressures, low enough vis-cosity index to flow properly when cold and highenough to retain film strength when subjected toheat exposure on cylinder and piston walls. Thelubricant must neutralize harmful combustionproducts and hold them in suspension for theduration of the oil change period. Your localCaterpillar Dealer should be consulted to deter-mine the best lubricant for local fuels.

The 3600 Series diesel engines and all Gasengines have different, unique oil specificationsand requirements.

Cleanliness

Normal engine operation generates a variety ofcontamination — ranging from microscopic metalparticles to corrosive chemicals. If the engine oilis not kept clean through filtration, this contam-ination would be carried through the engine viathe oil.

Oil filters are designed to remove these harmfuldebris particles from the lubrication system. Useof a filter beyond its intended life can result in aplugged filter.

A plugged filter will cause the bypass valve toopen releasing unfiltered oil. Any debris particlesin the oil will then flow directly to the engine.

Solid particles are removed from the oil bymechanical filtration. Filter mesh size is deter-mined by the maximum particle size that can becirculated without noticeable abrasive action.Standard oil filter systems on Caterpillar Enginesmeet these requirements and are sized to pro-vide reasonable time intervals between elementchanges. Filter change intervals relate to oilchange periods.

Caterpillar filters are designed to providemaximum engine protection. Use of genuine

Caterpillar elements is encouraged for adequateengine protection.

Larger oil pans are available on some engines.They provide increased oil change intervalsand/or increased tilt angle capability.

Lubricating Oil RequirementsSulfur content of today’s diesel fuels is increas-ing in certain areas. Fuel supplies around theworld are limited and in order to maintainneeded quantities, refineries are buying crude oilwherever available. Sulfur levels of these crudeoils vary significantly. Sulfur content of refineddiesel fuel is dependent upon the amount of sul-fur in the crude supply, and the refiner’s abilityto remove it.

When diesel fuel is burned in the engine’s com-bustion chamber, fuel sulfur is converted to sul-fur oxides. These compounds will unite withwater vapor to form acids. When the vapors cooland condense in the valve guides or in the pis-ton ring belt area, the acids attack metal andcause corrosive wear. One function of the enginelubricating oil is to neutralize the acids and retardmetal corrosion.

One factor that influences the formation of cor-rosive acids is the engine jacket water outlettemperature. If the outlet temperature is below175°F (70°C), acid vapor is readily formedbecause of the lower dew point temperature andcorrosion can occur. This is true even in fuelswith less than 0.5% sulfur. Under the above con-dition, the fuel performs as if it contained twoto three times the percent of sulfur that it actu-ally has.

When corrosion occurs, the usual signs are linerwear and ring wear. However, top ring wear isnot caused by corrosion but by the ring work-ing/sliding against a pitted surface. This pittedsurface can peel layers of chrome off the ringsurfaces. Ring and liner wear will result in exces-sive oil consumption.

Also, the water content of the oil increasesbecause of the lower temperature. The watercan react with the additives, deplete them andform sludge. This reduces the oil’s protectiveproperty.

LUBRICATION

131 LEBW1414-00

Additives

Lubricating oil consists of a mixture of base oilfortified with certain additives. Depending onthe type of base, paraffinic, asphaltic, naph-thenic or intermediate (which has some of theproperties of the former), different additivechemistries are used.

Certain lubricating oil additives contain alkalineconstituents which perform the neutralizing func-tion. The measure of alkalinity in a lube oil istermed TBN or Total Base Number. Oils havinghigh initial TBN values will generally have morereserve alkalinity or acid neutralizing capacity.To minimize engine corrosive wear caused byincreases in fuel sulfur levels, engine oils withhigher alkalinity reserve (TBN) are essential.

Guidelines have been developed to be used inthe selection of engine lubricating oils that maypermit standard oil drain intervals when usingdiesel fuel with up to 1.5% sulfur content. This canbe accomplished through use of oils with appro-priate alkalinity reserves (new oil TBN values)and satisfactory verification procedures listed inoil analysis.

Figure 8.1 contains the necessary information toselect the appropriate new oil alkalinity value(TBN) for the sulfur level in the fuel being used.

It must be kept in mind the new oil recommendedTBN value will provide acceptable performanceup to the standard drain interval, and we do notrecommend selecting oils with significantlyhigher TBN values. More than 5 TBN above rec-ommended is not advisable.

High Sulfur Fuels

Caterpillar lube oil change period recommen-dations are based on the use of diesel fuels con-taining 0.4% or less of sulfur by weight. Fuelsulfur can produce rapid engine wear. Fuels ofhigher sulfur content than 0.4% will requirereducing the oil change interval and/or use ofhigh TBN oil. These measures reduce the cor-rosive effect of the sulfuric acid that is formed bythe sulfur and other by-products of combustion.

The properties of the specific lube oil used, loadfactor, and other variables may affect the rateof wear due to sulfur. The lube oil supplier shouldbe consulted for the analysis parameters andlimits which will assure satisfactory engine per-formance with his products.

TBN by “ASTM D2896”Percentage of fuel sulfur by weightTBN of new oilChange the oil when the TBN deteriorates to 50% of the original TBN

Figure 8.1

2

1

X

Y

10 0.5 1.0 1.5 2.0 2.5 3.0

3

5

7

9

11

13

15

17

Y X

2

1

% FUEL SULFUR, BY WEIGHT

TB

N

Contamination

Contamination refers to the presence of unwantedmaterial or contaminants in the oil. There areseven major contaminants.

1. Wear ElementsWear elements are regarded as those ele-ments whose presence indicates a part orcomponent which is wearing. Wear ele-ments include: copper, iron, chromium, alu-minum, lead-tin, molybdenum, silicon,nickel, and magnesium.

2. Dirt and SootDirt can get into the oil via air blowing downpast the rings and by sticking to the oil filmand being scraped down from cylinder walls.Soot is unburned fuel. Black smoke and adirty air filter indicate its presence. It causesoil to turn black.

3. FuelUnburned fuel may enter under cold condi-tions or enter when the engine is not run-ning, but with a high static fuel pressure.

4. WaterIt can condense in the crankcase if theengine operating temperature is insufficient.The usual means of entry is via leaks.

5. Ethylene Glycol/Antifreeze

6. Sulfur Products/Acids

7. Oxidation ProductsOxidation products cause the oil to thicken;oxidation rate is accelerated by high tem-perature of the inlet air.

Scheduled Oil Sampling (S•O•S)Many Caterpillar Dealers offer Scheduled OilSampling as a means of determining enginecondition by analyzing lubricating oil for wearparticles. This program will analyze the wearrate of your engines, indicate any shortcomingsin engine maintenance, show first signs of exces-sive wear which would mean an upcoming fail-ure, and help keep repair costs to a minimum.

This program may not indicate lube oil conditionnor predict a fatigue or sudden failure. Caterpillarrecommendations for oil and oil change periodsare published in Service Literature. Caterpillardoes not recommend exceeding published oilchange recommendations without verificationprocedures.

Oils of the same alkalinity value may not per-form the same. Oil alkalinity can be achievedthrough a variety of additive formulations; someare more effective against acid corrosive wearthan others. For this reason, it will be necessaryto closely monitor engine wear with ScheduledOil Sampling (S•O•S) — Atomic AbsorptionWear Analysis. If oil recommendations are fol-lowed and excessive wear is indicated by unac-ceptable levels of iron (Fe) and chromium (Cr)wear particles, it will be necessary to shortenthe oil change interval or change to another oilof higher TBN value. If such oils are not avail-able, S•O•S can provide the information nec-essary to establish the maximum limit for areduced drain interval.

Other S•O•S elements (e.g., copper, aluminum,tin and silicon) should not be ignored, however,since acid corrosion is not the only cause ofengine wear. Infrared analysis can provide oilcondition information indicating problems thatmay be contributing to engine wear.

If the means are available to analyze used oilTBN by ASTM D2896, use Figure 8.1 to deter-mine the minimum TBN allowable in used oil.Minimum allowable TBN is determined by fuelsulfur content. These limits are higher for pro-portionately higher fuel sulfur contents. Con-trolled laboratory tests have demonstrated thisis necessary because oil alkalinity concentra-tion in critical areas having only small amountsof oil (valve guides and piston ring belt areas)must be proportionately higher to effectivelyneutralize the higher quantities of acids pro-duced in those areas.

Coping with effects of fuel sulfur is not a simpleproblem. Oils with larger quantities of acid neu-tralizing components will have higher ash con-tents. This may increase deposits on exhaustvalve heads and turbocharger nozzle rings. Eventhough proper use of lubricants and oil drainintervals reduce the degree of corrosive attack,engine wear will increase when high sulfur fuelis used.

Synthetic Lubricants

Caterpillar Inc. neither endorses nor recommendsa brand or type of extended oil drain intervalcrankcase oil for its engines.

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133 LEBW1414-00

Crankcase oil is changed because it becomescontaminated with soot (unburned carbon),wear products, partially burned fuel, acids,dirt, and products of combustion. The additivecomponents included in the oil become depletedas they perform their intended functions of dis-persing soot, preventing oxidation, wear, foam-ing, etc. Caterpillar requires engine crankcaselubricants to meet Engine Service DesignationAPI CH-4.

Special Oil Formulations

Caterpillar does not recommend the use of addi-tives to extend oil change periods. Oil additivessuch as graphite, teflon, molybdenum disulfide,etc., which have been properly blended into anoil that meets API CH-4 specification can beused in Caterpillar Diesel Engines. These addi-tives are not necessary to achieve normal lifeand performance of the engine.

Normal engine life and performance can beachieved by properly applying the engine, byservicing at recommended oil change period,by selecting the correct oil viscosity, by using aAPI CH-4 oil, and performing maintenance asoutlined in the engine operation and mainte-nance guide.

Caterpillar does not recommend the use ofmolybdenum dithiophosphate friction modifieradditive in the engine oil. This additive causesrapid corrosion of bronze components inCaterpillar Diesel Engines.

Lubricating OilOils meeting Engine service classificationAPI CH-4 are recommended for CaterpillarDiesel Engines. Publication “Caterpillar Com-mercial Diesel Engine Fluids Recommenda-tions,” form SEBU6251-06, contains completeinformation.

Viscosity is the property of oil which defines itsthickness or resistance to flow. Viscosity isdirectly related to how well an oil will lubricateand protect surfaces that contact one another.Oil must be provided in adequate supply to allmoving parts, regardless of the temperature.The more viscous (thicker) an oil is, the strongerthe oil film it will provide.

The required viscosity is listed in Figure 8.2.Multiviscosity oils are acceptable. In extremecold weather operation, where engines arelocated in enclosed heated rooms, some oper-ators and contractors prefer to make their oilviscosity selection based on the expected rangeof temperature within the engine room. After awinter rig move, this may require use of spaceheaters in the engine room for an extendedperiod of time before the engines can be started.

Figure 8.2

Lubricating Oil Heaters

Caterpillar does not recommend the use ofimmersion-type lubrication oil heaters due to theirtendency to overheat the oil in contact with theheating element. This overheating causes dete-rioration and sludging of the lubricating oil andmay lead to premature engine failure.

To avoid this condition, when using an oil heater,heater skin temperatures should not exceed300°F (150°C) and have a maximum heat den-sity of 8 W/in2 (12.5 W/1000 mm2).

Prelubrication3512 and 3516 Vee-type engines have the capa-bility to prelubricate all critical bearing journalsbefore energizing the starting motors.

The automatic system, standard on the 3516 drillrig engine utilizes a small air powered pump whichfills the engine oil galleries from the engine oilsump until the presence of oil is sensed at theupper portion of the lubrication system. Startermotors are automatically energized only after theengine has been adequately prelubricated.

Engine Oil ViscosityCaterpillar DEO Ambient Temperature

MultigradeEMA LRG-1

API CH-4 Minimum MaximumAPI CG-4

and API CF-4Viscosity Grade

SAE 0W20 –40°F (–40°C) 50°F (10°C)SAE 0W30 –40°F (–40°C) 86°F (30°C)SAE 0W40 –40°F (–40°C) 104°F (40°C)SAE 5W30 –22°F (–30°C) 86°F (30°C)SAE 5W40 –22°F (–30°C) 104°F (40°C)SAE 10W30 –4°F (–20°C) 104°F (40°C)SAE 15W40 5°F (–15°C) 122°F (50°C)

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Duplex Oil Filter SystemOilfield engines that require marine classificationsociety certification must be capable of oil filterchange while running.

The optional Caterpillar Duplex Oil Filter System(available for 3408, 3412, 3508, 3512, and 3516offshore engines) meets requirements of thestandard filter system plus an auxiliary filter sys-tem with necessary valves and piping, Figure 8.3.The system provides means for changing eithermain or auxiliary filter elements with the enginerunning at any load or speed. A filter change indi-cator is included to tell when to change the mainfilter elements. A vent valve allows purging of airtrapped in either the main or auxiliary systemwhen installing new elements. Air must be purgedfrom the changed section to eliminate possibleturbocharger and bearing damage. The auxiliarysystem is capable of providing adequate oil fil-tration for at least 100 hours under full load andspeed operation. The same filter elements areused in both systems.

Changing the filters when the engine is runningis not recommended when engine driven radia-tors are used since fan blast may disperse oil dur-ing filter change.

DUPLEX LUBE OIL FILTER

Figure 8.3

Remote FiltersSome Caterpillar Engines have the capability forremote mounting the oil filter when space limita-tion or serviceability is a problem on mobile typeland drill rigs. However, authorization fromCaterpillar Inc. must be obtained before makingany modification to the engine lubrication system.

While remote filters have more potential for oilleaks, they seldom cause problems when the fol-lowing recommendations are followed:

A. Exercise cleanliness during removal andinstallation of oil filters and lines. Keep allopenings covered until final connectionsare made.

B. Use medium pressure high temperature(250°F [120°C]) hose equivalent to orexceeding SAE 100R5 specification.

C Keep oil lines as short as possible and at leastas large as engine connections.

D. Support hose as necessary to keep fromchafing or cutting on sharp corners.

E. Use care in connecting oil lines so the direc-tion of oil flow is correct. CAUTION: Enginedamage will occur if oil filter is improperlyconnected.

Tilt AnglesInstallations at a permanent tilt or slant angleshould be reviewed to ensure the lubrication sys-tem will function properly. Transient and contin-uous tilt angle limits are shown for all engines inthe TMI.

Supplemental Bypass FiltersSupplemental filters generally fall into two cate-gories. The first are centrifugal filters. Centrifugalfilters remove solids from the oil such as sludge,wear materials, soot and carbonous material.Centrifugal filters can extend the operating hoursbefore the primary filters become restricted asindicated by oil filter differential pressure.

The second category of supplemental filters isabsorptive filters. Absorptive filters have anabsorbent media such as cotton or cellulosefibers which absorb acids, moisture and removecontaminants from the oil.

Caterpillar Engines usually do not require a sup-plemental bypass oil filter system. However theremay exist some unusual operating conditionwhich would cause the user to install a system.Centrifugal filters have proved helpful in extend-ing the primary filter life while absorptive filtersreduce acids and contaminants in the oil.

FUEL FILTER

OILFILTER

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If used, system must have a non-drainback fea-ture when the engine is shut down and a 0.125 in.maximum diameter orifice limiting flow to 2 gpm(7.57 L/min). Refer to engine general dimensiondrawings for recommended bypass filter supplylocation and oil return to the crankcase.

Supplemental bypass absorptive filters increaseoil capacity and may allow oil and filter changeperiods to be extended. However the drain inter-vals cannot be extended arbitrarily. Oil and filterlife must be verified by adequate monitoring sys-tems. Refer to the Caterpillar Operation Guide forrecommended change periods.

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FUEL DELIVERY SYSTEM

System DescriptionThe diesel engine fuel supply, delivery, and gov-erning systems have one primary purpose — todeliver clean fuel at the precise quantity and timeneeded to produce the required engine perform-ance. To do this many precision components areneeded but the two major devices are the fuelinjection pump and the governor which controlsit. The fuel system supplied on a Cat Engine isessentially complete, requiring only the hookupof fuel supply and return lines to a fuel tank, andconnection of governor controls.

A complete fuel system includes all of the follow-ing basic devices also shown by schematic below.

In addition to these basic features, other devicesare frequently used to provide additional func-tions or to modify one of the basic functions.Examples are fuel heaters, primary filters, duplexfilters, fuel coolers, air-fuel ratio controllers, loadlimiters, ether aids, load indicators, flow meters,gauges, and shutoffs.

A complete fuel system includes all of the fol-lowing basic devices also shown by schematicbelow:

1. Fuel Tank

2. Water Separator or Primary Filter

3. Transfer Pump

4. Secondary Filter

5. Injection Pump

6. Injection Lines }or unit fuel injector

7. Injection Valves

8. Fuel Pressure Regulator

9. Priming Pump

10. Fuel Pressure Gauge

11. Governor and Controls

12. Low Pressure Lines and Fittings

13. Fuel Cooler

Fuel is drawn from the tank (1) through theoptional water separator or primary fuel filter (2)by the engine-driven fuel transfer pump (3) andpumped through the secondary fuel filter (4) intothe injection pump housing reservoir (5) (or indi-vidual cylinder unit injector) and maintained at

low pressure. It is injected by individual high pres-sure pumps into each cylinder through specialhigh pressure fuel lines (6) to individual injectorscontained in the cylinder head (DI).

Fuel in excess of engine demand is bypassedthrough a pressure regulating valve (8) where allor part of it returns to the fuel tank along withany air which may have been purged out of thesystem. On modern, unit fuel injected engines,the fuel flow also cools the injector. Fuel flow rateis approximately 6 times the full load fuel con-sumption rate. Fuel coolers (13) may be requiredto prevent excessive fuel temperature.

For every 10°F (6°C) that the fuel temperaturerises above 100°F (38°C) the engine loses about1% of the gross horsepower as a result of theexpansion of the fuel (low viscosity). With verylow viscosity, the fuel loses the capability tolubricate and damage to the injection compo-nents will occur. To avoid this, the maximum fueltemperature should not at any time exceed150°F (66°C).

If the system is drained, as during repair or filterchange, a hand-operated fuel priming pump (9)is used to fill the system and expel the air. A pres-sure gauge (10) shows pressure of filtered fuelsupplied to the injection pump. If filters becomeplugged and require replacing, the gauge willread low when the engine is operating at load.The governor (11) controls the individual fuelrates from shutoff to full delivery in order toachieve desired engine speed, regardless of load.

Component Description andInstallation RequirementsIndividual components of the fuel system aredescribed here more completely as to purpose,recommended features, and installation require-ments to achieve satisfactory performanceand life.

Fuel Tank

It provides fuel storage and should have the fol-lowing features:

Adequate size for the intended application.

The capacity of a fuel tank or tank system can beestimated by multiplying the average horse-power demand by the hours of operation between

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refuelings, and divide the result by 16 for U.S.gallons and by 4 for liters.

This calculation does not allow for any reservecapacity which should be added to this basicrequirement.

Appropriate material. Steel, aluminum, stainlesssteel, or copper clad steel is used successfully.

Fuel tanks are best made from low carbonrolled steel.

Water in fuel produces a voluminous, white cor-rosion product when in contact with zinc.

Do not use zinc on significant surface area itemssuch as fuel tanks and lines which have potentialfor sitting in contact with stagnant pools of waterfor long periods of time. Fittings made of brass orcoated with zinc should be acceptable because oflimited exposure to stagnant water and a lack ofsufficient surface area to produce enough corro-sion product to cause plugging problems. Gal-vanized steel is essentially the same as zinccoated material.

The fuel tank must meet stringent corrosion pro-tection and leak detection regulations.

Expansion volume must be adequate to allow forexpansion of stored fuel during temperaturechange. Allowance of 5% of tank volume is ade-quate. This can be provided by extending thefiller neck down into the tank enough to create

the required expansion volume. A small vent hole(about 0.19 in. [4.81 mm] diameter) in filler tube,just below top of tank, is required to make thisvolume usable.

Venting to atmospheric pressure is necessary toprevent pressure or vacuum buildup. A large tankcan be collapsed by vacuum or burst by pres-sure if not vented properly. The vent shouldinclude a filter.

Filler must be adequately sized and located forconvenient filling. It should also be lockable. Fuelspillage must not reach hot parts. Also, fuelspillage should not reach items which can soakup or entrap fuel or be damaged by fuel.

A 2° sloping bottom helps collect sediment andany major amounts of water, and a bottom drainis necessary to permit periodic removal of thesecontaminants.

Fuel supply pickup should be off the bottomenough to leave 3% to 5% of the fuel in the tank.This should leave sediment and water in the tankuntil drained off periodically.

Fuel return line should normally enter the tankat the top and extend downward, exiting abovethe fuel level. Inlet and return lines should be sep-arated in the tank by at least 12 in. (204.8 mm)to avoid air pickup in the inlet line.

The fuel tank should be grounded.

REPRESENTATIVE BASIC FUEL SYSTEM(CONSULT TMI SCHEMATICS FOR EACH SPECIFIC MODEL)

Figure 9.1

Tank Maintenance

Fuel has a finite storage life of approximately oneyear, although this may vary widely dependingupon initial quality, contaminant levels and stor-age conditions. Periodic exchange of fuel and fil-tering/treating to remove water, scale andbacteria growth will extend fuel life.

Water contamination of fuel during long-termstorage offers a medium for bacterial growth,forming a dark slime which:

• Plugs filters• Deposits on tank walls and pipes• Swells rubber products that it contacts

Sulfur compounds are natural antioxidants, sothe low sulfur fuels (0.05% by weight) now avail-able will degrade quicker in storage. The dieselfuel will oxidize and form gums and varnisheswhich can plug fuel filters and injectors.

Because microorganism growth occurs in thefuel/water layer, the tank should be designed tominimize this interface, and water bottoms shouldbe drained regularly.

Microbiocide additives, either water- or fuel-sol-uble, can be added to fresh fuel to inhibit microor-ganism growth. Consult your local fuel supplierfor recommended additives.

In warm climates, large bulk storage diesel fuelrequires full filtering every six months to one year.

Every two years fuel should be completelychanged to remove water, scale, bacteria growth,oxidized gums/resins, and minimize filter clog-ging due to fuel separation into components suchas asphaltenes.

Fuel Coolers

A fuel cooler may be required on engines withunit fuel injectors, such as the 3500 series.Typical applications will be those where the fueltank is exposed to high ambient temperaturesor where there are restrictions to the size of thetank. The fuel temperature must be kept below150°F (66°C).

By reducing the temperature of fuel and remov-ing harmful particles, coolers and filters improvethe quality of the fuel used by an engine.

The excess fuel returned from some enginesequipped with unit injectors (1.7 liter, and 3500Family Engines) can absorb considerable heatfrom the injectors and the surrounding jacket

water. Fuel coolers may be necessary for properengine performance. The following factors affectthe need for fuel cooling equipment:

Length of periods of continuous operation: If theoperating periods are short, the amount of heatreturned to the fuel tanks will be relatively small.Fuel coolers are not generally required forengines used in high performance applications,such as fracturing.

Length of time between periods of operation: Ifthe time between periods of operation is long, theheat will have an opportunity to dissipate.

Volume of the fuel tank: If the volume of the fueltank is large (larger than 3,000 gal. (11 000 L)per engine, it will accept a great deal of heatbefore the temperature of the fuel leaving the tankincreases significantly.

Local experience may modify these recommen-dations, particularly in hot climates.

Offshore Rigs

Offshore rigs should have a fuel day tank installedin the engine room, Figure 9.2. All engine fuelsupply and return lines (or manifolds) should beconnected to this tank. This allows for venting ofany air that may enter fuel delivery system.

The day tank’s fuel level when full should notexceed the top of the injection valves. If the fulllevel is higher, static pressure in the supply andreturn lines may allow fuel to leak into combus-tion chambers when the engine is not running.Engine damage can result.

Where it is customary to install a large fuelday tank at the top of the engine room, an aux-iliary day tank should be mounted near theengine room deck and float fed from the largertank Figure 9.2. A capacity of 100-300 gal.(379-1136 L) is sufficient. The auxiliary day tankisolates the pressure head of the day tank fromthe engine fuel system.

Land Rigs

For land rigs the fuel day tank refill mark must notbe more than 12 ft. (3.65 m) below the enginefuel transfer pump. If the fuel day tank is morethan 30 ft. (9.15 m) from the engines or if ambi-ent temperature is extremely low, larger fuel sup-ply and return lines should be used to ensureadequate flow. The fuel day tank should have

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Figure 9.3

provisions to vent air in case it enters the fueldelivery system.

Elevated fuel tanks for land rigs should not exceedthe limitations, Figure 9.2.

Where a portion of the rig engines are elevatedon a substructure, 100 gal. (380 L) day tanksinstalled next to each engine improve startabil-ity and isolate ground level engines from highstatic fuel pressure. This requires an electric fueltransfer pump at the main fuel tank location toprovide low pressure fuel to these individual floatcontrolled day tanks, Figure 9.3.

Mobile Rigs

Adequate fuel tank structural strength is requiredto avoid failure under application conditionswhich may include shock loading and steadyvibration.

Baffles reduce sloshing and resulting air entrain-ment. They also prevent sudden shifts in thetank’s center of gravity, when in motion, as on amobile machine.

Strong fastening of the fuel tank to the machineis essential. This is especially important on amobile application where motion of a full tankgenerates sizeable forces. It is good practice touse some nonmetallic cushioning materialbetween the tank and support members to avoidfretting and wear on the tank.

Filler must be adequately sized and located forconvenient filling. It should also be lockable. Fuelspillage must not reach hot parts. Also, fuelspillage should not reach items which can soakup or entrap fuel or be damaged by fuel.

Filler should be located near center of tank sothat parking a mobile machine on a side tilt will

FUEL SUPPLY SYSTEMS

Figure 9.2

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not cause expanding fuel to back up into fillerpipe and overflow. This will also help avoidspilling fuel from a full tank when operating ona grade.

Fuel tanks should be shielded or located awayfrom major heat radiating sources such as hotexhaust manifolds and turbochargers. Also, thecooling fan blast picks up enough heat from theradiator to raise fuel temperatures significantly ifthe air is directed at the fuel tank. This will resultin some power loss because of the heated,expanded fuel.

Water Separator and Primary Filter

Clean fuel meeting Caterpillar’s recommenda-tions assures maximum engine service life andperformance; anything less is a compromise andthe risk is the user’s responsibility. Dirty fuel notmeeting Caterpillar’s minimum fuel specificationswill adversely affect combustion, filter life, starta-bility and life of internal components.

Clean fuel is of utmost importance to fuel injec-tion system components if long, trouble-freeservice life is expected. All Caterpillar Enginesare equipped with a main micronic filter systemto protect the fuel injection pumps and valves.These filters are not designed to cope with greatquantities of sediment and water. Both impuri-ties should be removed by an optional primaryfilter. A fuel centrifuge used in place of a waterseparator is acceptable. A primary fuel filtershould still be used because of contaminantsthat may be in the tank and piping as a result ofconstruction.

The system should be located ahead of any fuelpumps since pumps have a tendency to emul-sify the water with the fuel, which will reduce theefficiency of the water trap. Give close attentionto the system’s restriction since this will reducethe fuel pump lift capability.

Any system can be damaged by water in the fuel;so water should be removed. Fuel system dam-age by water is always the responsibility ofthe user.

The water separator should be sized adequatelyto separate and store enough water between peri-odic drainings to prevent overfilling and watercarryover into the engine’s fuel system.

The water separator should be mounted in a vis-ible location. If the operator sees water, he is more

likely to drain it out periodically. If the device ishard to see or difficult to service, it may notreceive regular attention.

The installation should include valves which canisolate the separator and primary filter when ele-ments are changed.

Excessive amounts of water, slimy material onfilters, corrosion of fuel system components, ortank coatings may indicate fungus/bacteria inthe fuel. Contact your fuel supplier for test kits todetermine the degree of contamination andchemical additives to prevent recurrence.

Because water can collect and freeze at lowpoints in fuel lines, filters, or other componentsthat contain fuel, a water separator should beplaced as close to the fuel tank as practical in avisible, serviceable location. Usually, the sepa-rator has a see-through feature that allows aquick visual check for presence of water and aquick-drain valve to let water out.

Lines and Fittings

Pipes, hoses, and fittings must be mechanicallystrong, leak-tight, and resistant to deteriorationdue to age or environmental conditions. Sizingmust be adequate to minimize flow loss. Routingmust be correct, and flex connections, such ashose assemblies, must isolate engine motionfrom the stationary members in the system.

The pipes should be of the same material as thetank, black iron or steel to avoid reaction withthe fuel.

Copper pipe or tubing may be substituted in sizesof 0.5 in. (13.0 mm) nominal pipe size or less.Valves and fittings may be cast iron or bronze(not brass).

Do not use zinc alloy or galvanized metal due toits high chemical reaction with fuel.

The size of the pipe should be the same as thesize of the engine fuel inlet.

Piping and fittings must be sealed to prevent airor dirt contamination. Air in the system causeshard starting and erratic engine operation.

Determine the fuel line sizing by the supply andreturn line restriction. The maximum allowablerestriction is published in the TMI. Supply andreturn lines should be no smaller than the fittingson the engine.

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Figures 9.4 and 9.5 provide useful frictionalloss data.

Engine fuel pressure measured in the fuel returnline should be kept below 4 psi (27 kPa), exceptfor the 3300 Engine Family, which is 3 psi(20 kPa). A shutoff valve is not recommended,for 3400 Series or smaller engines because dam-aging pressure may result if the valve were leftclosed when engine was started.

If the engine is above the fuel tank, consideradding a check valve to the fuel supply line tokeep fuel from bleeding back to the fuel tank caus-ing hard starting.

Fuel lines should be designed with the applicationin mind. Especially on mobile, off-highwayequipment, effects of vibration, shock loads, andmotion of parts should be considered. Fuel linesshould be well routed and clipped, with flexiblehose connections where relative motion is pres-ent. Lines should be routed away from hotparts, like manifolds and turbochargers, to avoidfuel heating and potential hazard if a fuel lineshould fail.

Joints and fittings must be leak-tight to avoidentry of air into the suction side of the fuel system.A joint which is leak-tight to fuel can sometimes

allow air to enter the fuel system, causing erraticrunning and loss of power. Pipe joint compoundshould be used on pipe threads, taking care tokeep it out of the fuel system where it can causedamage.

Routing

Whenever possible, route fuel lines under anymachinery so any leakage will be confined tothe bilges or drip pans under machinery. Leaksfrom overhead fuel system components may fallonto hot machinery, increasing the likelihood offire danger.

Fuel lines should also be routed to avoid forma-tion of traps which can catch sediment or pock-ets of water which will freeze in cold weather.

All connecting lines, valves, and tanks should bethoroughly cleaned before making final connec-tions to the engine. The entire fuel supply sys-tem should be flushed prior to engine startup.

Transfer Pump

This engine driven pump delivers low pressure(15 psi to 30 psi [103 kPa to 207 kPa]) fuel fromthe tank to the injection pump housing reservoir(60 psi [414 kPa] on 3508, 3512, and 3516). It

Figure 9.4. Frictional head loss, pipes.

Figure 9.5. Frictional loss in pipe fittings.

Frictional Loss in Pipe Fittings in Terms of Equivalent Feet (Meters) of Straight PipePipe Ball 45° Std. Std. Check Angle Globe DiaphragmSize Valve Elbow Elbow Tee Valve Valve Valve Valve(in.) ft. (m) ft. (m) ft. (m) ft. (m) ft. (m) ft. (m) ft. (m) ft. (m)3/8 0.28 (0.085) 0.70 (0.213) 1.4 (0.427) 2.6 (0.792) 3.6 (1.1) 8.6 (2.62) 16.5 (5.03)1/2 0.35 (0.107) 0.78 (0.238) 1.7 (0.518) 3.3 (1.01) 4.3 (1.31) 9.3 (2.83) 18.6 (5.67) 40 (12.19)3/4 0.44 (0.134) 0.97 (0.296) 2.1 (0.64) 4.2 (1.28) 5.3 (1.62) 11.5 (3.51) 23.1 (7.04)1 0.56 (0.171) 1.23 (0.375) 2.6 (0.792) 5.3 (1.62) 6.8 (2.07) 14.7 (4.48) 29.4 (8.96)

1-1/4 0.74 (0.226) 1.6 (0.488) 3.5 (1.07) 7.0 (2.13) 8.9 (2.71) 19.3 (5.88) 38.6 (11.77)1-1/2 0.86 (0.262) 1.9 (0.579) 4.1 (1.25) 8.1 (2.47) 10.4 (3.17) 22.6 (6.89) 45.2 (13.78)

2 1.10 (0.335) 2.4 (0.732) 5.2 (1.58) 10.4 (3.17) 13.4 (4.08) 29.0 (8.84) 58.0 (17.67)

Frictional Head Loss [ft. (m)] for 100 Feet (30.5 Meters) of Standard Weight Pipeat 60°F (15.5°C) at Seal Level — Diesel Fuel

GPM (L/min) Pipe Size3/8 1/2 3/4 1 1-1/4 1-1/2 2

2 (7.57) 15.2 (4.63) 5.5 (1.67) 1.1 (0.34) 0.5 (0.15) 0.2 (0.06)4 (15.14) 55.5 (16.92) 20.3 (6.18) 5.1 (1.55) 1.4 (0.43) 0.5 (0.15) 0.2 (0.06)7 (26.5) 61.0 (18.59) 15.3 (4.66) 4.6 (1.4) 1.2 (0.36) 0.5 (0.15)

10 (37.85) 26.3 (8.01) 8.5 (2.6) 2.5 (0.76) 0.9 (0.27) 0.2 (0.06)19 (71.92) 28.5 (8.68) 7.5 (2.28) 3.5 (1.07) 1.2 (0.36)

is a gear-type pump with some limited primingcapability when the pumping gears are full of fuel.This pump should be protected from abrasivewear and corrosion by a water separator or pri-mary fuel filter.

Secondary Filter

Because fuel injection pumps and injectors areprecision devices with extremely close clearancesbetween working parts, particles which can causedamage must be removed in the secondary fil-ter. This filter is standard equipment on all CatDiesel Engines. When a secondary filter getsplugged, an engine typically loses power or mayrun erratically. The fuel pressure gauge will indi-cate low fuel pressure under these conditions.Filter media in Caterpillar fuel filters is developedand carefully controlled to conform with Cat spec-ifications on filtration efficiency and durability. Useof filters of unknown capability may not protectthe precision fuel system from contamination.

Fuel Pressure Regulator

Somewhere in the fuel path, before or at the injec-tion pump, there is a pressure regulating valvewhich limits the pressure of fuel supplied to theinjection pump housing reservoir. This pressuremust be enough to fill the individual injectionpump assemblies, but would become excessiveif the transfer pump could not pump excess fuelthrough a relief circuit back to the fuel tank. Ashutoff valve should never be placed in the fuelreturn line because pressure may quickly build todamaging levels, depending upon the enginemodel. The return line also allows air to escapefrom the system.

3500 Series engines include a transfer pumprelief valve that protects the system if a returnline fuel shutoff valve is accidentally closed.

Priming Pump

When a fuel system has air in it, the hand prim-ing pump is used to fill the system with fuel andpurge air. Once this has been done, the primingpump will not likely be used again until the fuelsystem is emptied for adjustment or repair.

Injection Pump

Fuel is pumped at a very high pressure to eachcylinder unit injector. The fuel volume pumpedon each stroke is controlled by the rack (scrollsystem) or electric solenoid which determines

the effective pumping stroke. The governor con-trols fuel delivery to produce a governed speed,regardless of load.

Injection Lines

On some smaller engines, individual fuel linescarry fuel at the very high pressure required forinjection, from individual injection pumps to eachcylinder injector. These lines are heavy-walled,strong, specially extruded tubing made only forthis purpose. Because injection lines carry suchhigh pressure, they should not be bent or dam-aged during installation or operation.

Injectors

The purpose of the injector valve is to spray thecorrect pattern of atomized fuel into the com-bustion chamber (DI). It has a spring-loadedvalve which requires that the pressure rise tosome elevated level before valve opens at startof injection. This is necessary for a precision-timed fuel delivery and assures a sharp cutoff offuel at the end of each injection period.

Most emissions certified engines utilize unit injec-tors. No high pressure injection lines are required.

Fuel System AttachmentsDuplex Fuel Filter System

Oilfield engines that require marine classificationsociety certification must be capable of fuel filterchange while running. The optional Caterpillarduplex fuel filter system (available for 3406,3408, 3412, 3508, 3512, and 3516 Engines)meets the requirements of the engine and marinesocieties, Figure 9.6. Main and auxiliary filter sys-tems are combined in one housing. The systemprovides for changing either main or auxiliary fil-ter elements with the engine running at any loadand speed. A vent position in the control valveallows purging of air trapped in the housing wheninstalling new elements. Both main and auxiliarysections can be used simultaneously to extendrunning time in an emergency. The auxiliary sys-tem provides at least 100 hours full load runningtime with reasonably clean fuel.

This system can be used when engine drivenradiators are used, but only to select the standbyfilter. Filter changing during engine operation isnot recommended due to safety concerns aroundhot surfaces and due to fuel being blown aroundby the radiator fan air flow.

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DUPLEX FUEL FILTER1. Fuel Filter Housing2. Priming Pump3. Changeover Valve Handle

Figure 9.6

Double-Wall Fuel LinesOn engines without unit injectors, double-wall fuellines are required by marine classification soci-eties for unmanned engine rooms and othernational association regulations on fire prevention.

The system contains high pressure steel fuel linesinside steel tubes. The fuel line assembly bleedsoff fuel that may have leaked from the maininjector line to a collecting tank.

The tank contains a float switch which can bewired to a warning alarm that activates when thetank fills. The tank can be connected to a largerreservoir.

Fuel SpecificationsClean fuel meeting Caterpillar’s fuel recommen-dations assures maximum engine service life andperformance; anything less is a compromise andthe risk is the user’s responsibility. Dirty fuel andfuels not meeting Caterpillar’s minimum fuelspecifications will adversely affect combustion,filter life, injection system performance and serv-ice life, startability and/or, perhaps, service lifeof valves, pistons, rings, liners, and bearings.

Fuel costs can represent 80% or more of totalengine operating costs; it is good economics tocarefully consider proper fuel selection.

Fuel normally recommended for diesel genera-tor sets is No. 2 furnace oil or No. 2D diesel fuel.

Caterpillar Engines burn a variety of fuels.Generally, use the lowest priced distillate fuelwhich meets the following requirements (fuelcondition as delivered to engine fuel filters).

Fuel specifications meeting the above require-ments include:

• ASTM D396 — No. 1 and No. 2 Fuels(Burner Fuels)

• ASTM D975 — No. 1-D and No. 2-D DieselFuel Oil

• BS2869 — Class A1, A2, B1, and B2 EngineFuels

• DIN51601 — Diesel Fuel

• DIN51603 — EL Heating Oil

Preferred Fuels

Distillate fuels which meet the following require-ments are the preferred fuels for CaterpillarEngines:

Complete information on diesel fuels is in “DieselFuels and Your Engine,” form SEBD0717.

(Cont’d)

Caterpillar Specifications for Distillate Diesel FuelASTM

Specifications Requirements TestAromatics 35% maximum “D1319”Ash 0.02% maximum (weight) “D482”Carbon Residue 0.35% maximum (weight) “D524”on 10% BottomsCetane Number 40 minimum (DI engines) “D613”

35 minimum (PC engines)Cloud Point The cloud point must not —

exceed the lowest expectedambient temperature

Copper Strip No. 3 maximum “D130”CorrosionDistillation 10% at 540°F (282°C) “D86”

maximum90% at 680°F (360°C) maximum

Flash Point Legal limit “D93”API Gravity 30 minimum “D287”

45 maximum

FUEL FILTER

OILFILTER

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Figure 9.7

*A higher cetane number fuel may be required foroperation at a high altitude or in cold weather.

Permissible Fuels

There are exceptions to the distillate onlyCaterpillar recommendation for a suitable fuel.With the addition of special equipment, 3500Series low speed Cat Engines will perform satis-factorily on some crude oils and blended fuels.Since the composition of crude oils varies greatlyand since worldwide specifications of blendedfuels are very broad, special care must be takenbefore using such fuels in Cat Engines. Unsuit-able characteristics of such fuels and precondi-tioning requirements are discussed later.

Caterpillar has established the following guide-lines for fuel, as delivered to the fuel injection sys-tem, to determine the suitability of a fuel havingphysical and chemical properties not meetingCaterpillar Diesel preferred fuel requirements.

Fuel Properties

Cetane Number (ASTM D613) — Measure of theignition quality of a diesel fuel as determined inan engine. The higher the cetane number the bet-ter the ignition quality and the less the tendencyto knock.

Ignition delay also causes poor fuel economy, aloss of power and sometimes engine damage. A

low cetane number fuel can also cause whitesmoke and odor at start-up on colder days.Engines running on fuels with low cetane num-bers may need to be started and stopped usinga good distillate fuel.

Blended fuels or additives can change the cetanenumber. The cetane number is difficult andexpensive to establish for blended fuels due tothe complexity of the required test.

White exhaust smoke is made up of fuel vaporsand aldehydes created by incomplete enginecombustion. Ignition delay during cold weatheris often the cause. There is not enough heat inthe combustion chamber to ignite the fuel.Therefore, the fuel does not burn completely.

Using a cetane improver additive can oftenreduce white smoke during engine start-up incold weather. It increases the cetane number ofdiesel fuel which improves ignition quality andmakes it easier for fuel to ignite and burn. Contactyour local fuel supplier for information on whereto obtain cetane improvers.

Cetane number is usually calculated or approx-imated using a cetane index due to the cost ofmore accurate testing. Be cautious when obtain-ing cetane numbers from fuel suppliers.

Higher cetane numbers indicate a shorter igni-tion lag and are associated with better all-aroundperformance in most diesel engines, especially inhigh speed engines.

Specific Gravity (ASTM D287)

The specific gravity of diesel fuel is the weight ofa fixed volume of fuel compared to the weight ofthe same volume of water (at the same temper-ature). The higher the specific gravity, the heav-ier the fuel. Heavier fuels have more energy orpower (per volume) for the engine to use.

Lighter fuels like kerosene will not produce ratedpower. (Specification sheets usually show ratingswhen using fuel having 35 API density, at 85°F(29°C), weighing 7.001 pounds per gallon, andhaving 18,390 BTU’s per pound. The same fuelof 35 API density weights 7.076 pounds per gal-lon at 60°F (15°C). When comparing fuel con-sumption or engine performance, always knowthe temperature of the fuel measurement for cor-rect gravity and density.

Engine fuel settings should not be adjusted tocompensate for a power loss with lighter fuels

Caterpillar Specifications for Distillate Diesel FuelASTM

Specifications Requirements TestPour Point 10°F (6°C) minimum below “D97”

ambient temperatureSulfur 3% maximum “D3605”

or“D1552”

Kinematic 1.4 cSt minimum and “D445”Viscosity 20.0 cSt maximum at

104°F (40°C)Water and 0.1% maximum “D1796”SedimentWater 0.1% maximum “D1744”Sediment 0.05% maximum (weight) “D473”Gums and 10 mg per 100 mL “D381”Resins maximumLubricity 3100 g minimum “D6708”

0.018 in. (0.45 mm) “D6079”maximum at 140°F (60°C)0.015 in. (0.38 mm) maximum at 77°F (25°C)

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(with a density number higher than 35 API). Fuelsystem component life can be decreased withvery light fuels because lubrication will be lesseffective (due to low viscosity).

Lighter fuels may also be a blend of ethanol ormethanol with diesel fuel. Blending of alcohol(ethanol or methanol) or gasoline into a dieselfuel will create an explosive atmosphere in thefuel tank. In addition, water condensation in thetank can cause the alcohol to separate and strat-ify in the tank. Caterpillar recommends againstsuch blends.

Viscosity (ASTM D445 Kinematic Viscosity) —Measure of a fluid’s resistance to flow. It is ordi-narily expressed in terms of the time required fora standard quantity of the fluid at a certain tem-perature to flow under gravity through a cali-brated glass capillary viscosimeter. The higherthe value, the more viscous the fluid. Since vis-cosity varies inversely with temperature, its valueis meaningless unless accompanied by the tem-perature at which it is determined. With petro-leum oils, viscosity is commonly reported incentistokes (CST). Other viscosity units used areSaybolt seconds, universalsus or, Saybolt sec-onds, furol-SSF. Less common are the Englerand redwood viscosity scales, whose principalapplications are outside the U.S.A.

High viscosity fuel will increase gear train, camand follower wear on the fuel pump assemblybecause of the higher injection pressure. Fuelatomizes less efficiently and the engine will bemore difficult to start.

Low viscosity fuel may not provide adequatelubrication to plungers, barrels, and injectors; itsuse should be evaluated carefully.

Flash Point (ASTM D93) — Lowest temperaturefuel will give off sufficient vapor to ignite whenflame is applied.

Pour Point (ASTM D97) — Lowest temperatureat which fuel will flow, a factor of significance incold weather startup and operation. A pour pointof 5°F (3°C) lower than the ambient temperatureat which the engine will be expected to start andoperate should provide freedom from fuel filterplugging. If the fuel contains a pour point depres-sant, the cloud point is the significant temperature.

Cloud Point — Lowest temperature at which thesample becomes clouded by the formation ofwax crystals. If this temperature is no higher than

the lowest ambient temperature at which theengine will be expected to start and operate, fuelfilter wax plugging will not be a problem.

Sulfur (ASTM D1522 or D3605) — Fuel sulfurforms compounds during combustion whichreact chemically with the lubricating oil. Theyreduce the oil’s effectiveness in preventing theformation and accumulation of deposits on thepiston and piston rings. Sulfur compounds alsopromote corrosion and corrosive wear.

When diesel fuel containing sulfur is burned inan engine’s combustion chamber, oxides of sul-fur form and react with water vapor to create sul-furic acid. If these acid vapors condense, theychemically attack the metal surfaces of valveguides, cylinder liners, and may affect bearings.For example, when the temperature of the cylin-der liners is lower than the dew point of sulfuricacid, and the lubricating oil does not have suffi-cient alkalinity reserve (TBN) to neutralize theacid, liners can wear ten times more quickly.

When fuel sulfur damage occurs, there will bevery little change in engine power. But, frequently,corrosive wear will lead to excessive oil con-sumption and blowby, causing a premature,expensive overhaul.

Maintain the crankcase breather system to pre-vent condensation in the crankcase oil which willcause rapid TBN depletion.

Maintain a regular Scheduled Oil Sampling(S•O•S) oil analysis program. Infrared (IR)analysis is valuable as well.

Follow standard oil change intervals unless S•O•Sor known sulfur content indicates differently.

Caterpillar recommends reducing the length ofoil change periods or increasing crankcasecapacities or raising the operating water tem-perature to offset the effects of higher quantitiesof sulfur.

Water and Sediment (ASTM D1796) — The per-centage, by volume, of water and foreign matterwhich can be removed from fuel by centrifug-ing. These materials affect the rate of fuel filterplugging.

Salt water is the greatest single source of foulingdeposits and corrosion. Salt water can cause fuelinjector and piston ring groove deposits and wearin fuel system plunger and barrel assemblies.

The coalescing type of separator is recom-mended because often the water in the fuel ismixed or broken into small particles which donot settle. This separator is used if particles areso fine they make the fuel cloudy.

A coalescing type separator will separate allwater from fuel. It can be put anywhere in the fuelline, such as next to the components that needthe most protection from water. The elements arecomposed of two-stage paper media that arereplaceable. The element is plugged when thereis a lack of fuel pressure.

Make sure you know the percentage of sedimentin the fuel you purchase. If the sediment or waterfor distillate fuels exceeds 0.05% to the engine,consider other sources for fuel, or special filtra-tion, centrifuging or settling procedures. Fuelshould be tested often for both sediment andwater. Testing is the only way you can be assuredthat you are actually getting the quality of fuelyou paid for.

Sediment will gradually be caught in the fuel fil-ter, but this will cause added expense in moreperiodic filter changes. Very small sediment willget through the filters and can result in fuel sys-tem wear. It is important to remove as much sed-iment as possible before the fuel goes into yourengine. This will reduce the ash and particulatecontamination which causes deposits, corrosionand abrasive wear.

Allow time for sediment to settle to the bottomof the tank. Your engine will use the cleaner fuelat the top and you can drain the sediment fromthe bottom. However, as the specific gravitybecomes higher, the settling method of removingsediment becomes less effective.

Sludge and Fibers

Both sludge and fibers can contaminate fuel dur-ing handling and storage. Storage tanks, fuel pipelines and barge transportation all contribute tothese contaminants.

Fibers cannot be removed except by filtering.Sludge will rapidly foul the centrifugal purifiers.Both of these contaminants will clog strainersand fuel filters. If fuel with sludge is burned in theengine, it will cause filter fouling.

The only solution to a sludge or fiber problem isto replace (or clean) the filters often until the con-

taminating fuel supply is completely used, thenclean the fuel tank and use clean fuel.

Microorganisms in Fuel

All water and fuel offer a medium for bacterialgrowth. These simple life forms live in the waterand feed on fuel.

Microorganisms or fungi in fuel cause corrosionand filter plugging. Bacteria may be any color,but is usually black, green or brown. Bacteriagrows in long strings and has a slimy appear-ance. A biocide added to the fuel will kill thegrowth and/or slow its formation. Filtering thefuel, or proper disposal after using the biocide, isrequired to eliminate filter plugging.

Copper Strip Corrosion

Corrosion (ASTM Test D130), is a discolorationformed on a polished copper strip when immersedin fuel for three hours at 212°F (100°C). Any fuelshowing more than slight discoloration shouldbe rejected.

Many types of engine parts are of copper or cop-per alloys. It is essential that any fuel in contactwith these parts be noncorrosive to them. Thereare certain sulfur derivatives in the fuel that arelikely sources of corrosion.

Carbon Residue (ASTM D524) — Percentage byweight of dry carbon remaining when fuel isburned until no liquid remains.

Ash (ASTM D482) — Percentage by weight ofdirt, dust, sand, and other foreign matter remain-ing after combustion.

Fuel Stability

Gums and Resins

The gums and resins that occur in diesel fuel arethe result of dissolved oxidation products that donot evaporate easily or burn cleanly. Excessivegum in the fuel will coat fuel injection lines,pumps and injectors and will interfere with theclose tolerances of the fuel system’s movingparts. They will also cause rapid filter plugging.During fuel storage the fuel will oxidize and formmore gums and resins. Reducing fuel storageperiods (maximum of one year) will minimize theformation of gums and resins.

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Fuel Separation

Fuel must remain stable in storage. If not prop-erly refined, incorrect stability additives are used;or if fuel gets old, it can change its characteris-tics of being totally mixed to separating into com-ponents like asphaltenes. This will cause rapidfuel filter plugging and low engine power. To min-imize the occurrence of fuel separation, use goodquality fuel with the correct additives from a rep-utable supplier, and minimize the length of timethe fuel is stored. Do not store fuel for over a year.

Fuel Storage

Diesel fuel is more prone to oxidative attack instorage and to thermal degradation in use thangasoline because of more sulfur and nitrogen andhigher molecular weight components with higherdistillation end points. The sulfur removal processhelps stabilize the fuel by reducing sedimentforming products. But the use of cracked stocks(more unstable) has created the need for addi-tional treatment.

Commercial diesel fuels will usually contain avariety of additives that improve or add desirableproperties. Fuel stability additives are extensivelyused in diesel fuels to prevent oxidative break-down of the fuel into gums and polymeric sedi-ment during storage.

But the fuel still has a finite storage life which isusually limited to about one year. Care shouldalso be used to prevent water and other con-taminants from getting into the storage tanks toreduce the effectiveness of built-in resistance.

Mixing Used Crankcase Oil with Diesel Fuel

It is necessary to collect, store, and dispose ofused crankcase oil from engines due to legisla-tion and ecological considerations. It is no longeracceptable to dump used crankcase oil into theoceans, rivers, and harbors from vessels or off-shore drilling and production platform installa-tions. It may be necessary for engine operatorsto consider burning crankcase oil in their CatEngines. This can be done providing the pre-cautions below are carefully followed.

1. Only diesel engine crankcase oils can bemixed with the diesel engine fuel supply. Theratio of used oil to fuel must not exceed 5%.Premature filter plugging will occur at higherratios. Under no circumstances shouldgasoline engine crankcase oils, transmission

oils, special hydraulic oils not covered byCaterpillar recommendations, greases, clean-ing solvents, etc., be mixed with the dieselfuel. Also, do not use crankcase oils con-taining water or antifreeze from enginecoolant leaks or from poor storage practices.

2. Adequate mixing is essential. Lube oil andfuel oil, once mixed, will combine and notseparate. 1. Mix used crankcase oil with anequal amount of fuel, 2. filter, and 3. then addthe 50-50 blend to the supply tank beforenew fuel is added. This procedure should nor-mally provide sufficient mixing. Failure toachieve adequate mixing will result in pre-mature filter plugging by slugs of undilutedlube oil.

3. Filter or centrifuge used oil prior to putting itin the fuel tanks to prevent premature fuelfilter plugging or accelerated wear or plug-ging of fuel system parts. Soot, dirt, metal,and residue particles larger than 5 micronsshould be removed by this process. If filter-ing or centrifuging is not used prior to addingthe oil to the fuel, primary filters with5 microns capability must be located betweenthe fuel supply and engine. These will requirefrequent servicing.

4. Clean handling techniques of the used crank-case oils are essential to prevent introducingcontaminants from outside sources into thediesel fuel supply. Care must be taken in col-lecting, storing, and transporting the usedcrankcase oil to the diesel fuel tanks.

Diesel fuel day tank sight glasses may becomeblackened in time due to the carbon content inthe crankcase oil. Ash content of the lube oiladded to the fuel may also cause more rapidaccumulation of turbocharger and valve depositsthan normal.

Crude Oil Fuel SystemWhere economics justify or where limited fuel sup-plies necessitate, crude oil and heavier fuels (i.e.,distillate-residual blends) can be permissible fuelsfor Caterpillar 3500 Series low speed Engines.

Caterpillar does not recommend using any of theheavier fractions such as residuals or bottoms.Residual fuels or blended fuels with high (above20%) percentages of residuals are unsuitablebecause they have a high viscosity range, low igni-tion quality and vanadium and sodium contents

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that shorten engine life. Such fuels may causehigh wear rates in the fuel system, on the pistonrings, cylinder liners, and exhaust valves. Also, fil-ter problems and deposits in the piston ringbeltmay be evidenced.

Special fuel pretreatment equipment may berequired and is available from suppliers of fueltreatment equipment. Also, it may be essentialto start and stop the engine on a better quality,ASTM No. 2-D type fuel to prevent plugging andsticking fuel system components and to permitsatisfactory startability.

The same diesel power ratings may not alwaysapply for Caterpillar engines burning crude oil orheavy fuels. Reasonable engine service life canbe achieved when proper procedures are fol-lowed. However, the greater risks involved makeit good practice to include slightly higher thannormal maintenance costs when figuring theoverall economics to be gained.

A fuel analysis should be performed (see Fig-ure 9.8.). Include a distillation curve. Operationat light load is not recommended. On occasion,operation at 50% load has reportedly causedsmoking.

PPM = parts per million

Figure 9.8

Crude Oil ChartFuel Properties and Characteristics Permissible Fuels as Delivered to the Fuel System

Cetane number or cetane index Minimum 35(ASTM D613 or calculated index)(PC Engines)(DI Engines) Minimum 40Water and sediment % volume (ASTM D1796) Maximum 0.5%Pour point (ASTM D97) Minimum 10°F (6°C) below ambient temperatureCloud point (ASTM D97) Not higher than ambient temperatureSulfur (ASTM D2788 or D3605 or D1552) Maximum 0.5% — See page 133 to adjust oil TBN

for higher sulfur contentViscosity at 100°F (38°C) Minimum 1.4 cSt(ASTM D445) Maximum 20 cStAPI gravity (ASTM D287) Maximum 45

Minimum 30Specific gravity (ASTM D287) Minimum 0.8017

Maximum 0.875Gasoline and naphtha fraction Maximum 35%(fractions boiled off below 200°C)Kerosene and distillate fraction (fractions boiled off Minimum 30%between 200°C and cracking point)Carbon residue (ramsbottom) (ASTM D524) Maximum 3.5%Distillation — 10% Maximum 540°F (282°C)

— 90% Maximum 716°F (380°F)— cracking % Minimum 60%

Distillation — residue (ASTM D86, D158 or D285) Maximum 10%Reid vapor pressure (ASTM D323) Maximum 20 psi (kPa)Salt (ASTM D3230) Maximum 100 lb/1,000 barrelsGums and Resins (ASTM D381) Maximum 10 mg/100 mLCopper strip corrosion 3 hrs @ 100°C (ASTM D130) Maximum No. 3Flashpoint °F °C (ASTM D93) Maximum Must be legal limitAsh % weight (ASTM D482) Maximum 0.1%Aromatics % (ASTM D1319) Maximum 35%Vanadium PPM (ASTM D2788 or D3605) Maximum 4 PPMSodium PPM (ASTM D2788 or D3605) Maximum 10 PPMNickel PPM (ASTM D2788 or D3605) Maximum 1 PPMAluminum PPM (ASTM D2788 or D3605) Maximum 1 PPMSilicon (ASTM D2788 or D3605) Maximum 1 PPM

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Engines for crude fuel operation should beequipped with higher temperature thermostats,bypass centrifugal oil filter, and fuel injectorpushrod keepers.

Pretreatment of Crude Oils

First — The crude may contain excessiveamounts of sediment and water that will requireremoval before they get to the engine. This canusually be accomplished with a settling tank,Figure 9.9, a centrifuge or special filtering equip-ment or a combination of these methods. Thecrude may also contain solid particles of wax atambient temperature that would plug the filtersrapidly. It is impractical to try to remove the wax,but the crude can be heated sufficiently to dis-solve it. The amount of heat needed will vary fromone crude to another and will, therefore, have tobe determined in each situation. Frequently,jacket-water heated fuel filters, available fromfuel equipment suppliers, are adequate. If not, anexternal heating system will be necessary.

Second — The crude oil must not have too higha viscosity. For maximum life and minimummaintenance of the fuel pumping and injectionsystems, the viscosity of the crude oil in thesesystems should be within 1.4 to 20 cSt at 100°F(38°C). If the crude’s natural viscosity is higherthan this, it may be heated or diluted to reduce it.The degree of heating required will vary from onecrude to another and will have to be estab-lished in each case. Another method of reducingviscosity is to blend the original crude with a suf-ficient amount of lighter distillate material. Again,the blending proportions would have to bedetermined for each crude.

Third — The crude must have a cetane numberof at least 40. This brings its distillation charac-teristics into the picture. The cetane numbershould be determined by actual engine testbecause calculated numbers of crude oils areunreliable.

The cetane number of a crude is a function of itscomposition. Crude is generally subdivided intofractions by boiling temperatures. The combina-tion of the gasoline and naphtha fractions, whichhave low cetane numbers, should not exceed35% of the total crude. The kerosene, distillateand gas oil fractions combined should make upat least 30% of the total because they have highcetane numbers.

Fourth — Another problem created by highlyvolatile crudes (low initial boiling points) is vaporlocking of the fuel system. This situation can behandled by an “air eliminator.” This, in some cases,can be an ordinary float-type steam trap inverted,but it should be made of corrosion-resistantmaterials. It should be located after the auxiliaryfilters. If the engine is stopped occasionally andallowed to cool, coagulation may build up in thisvapor trap and cause it to be inoperative.

Fifth — The proper oil change recommendationmust be made in each case. Many crude oils con-tain large amounts of material that acceleratelube oil deterioration. For this reason, the stan-dard change period with recommended oilsshould be reduced one-half. From this point, thelength of change period with crude is determinedby sulfur content the same as with distillate fuels.With 0.4-1.0% sulfur, the change period shouldagain be reduced one-half. When sulfur contentexceeds 1.0%, still further reduction is recom-mended. In many cases, it may be desirable toinstall a larger capacity lube oil system to avoidshort oil changes.

Crude Oil Settling Tanks

A great deal of sludge can be removed fromcrude oil by proper settling. A recommended set-tling system consists of two cone-bottomedtanks, Figure 9.9, each holding a little more thanfour days usable supply of fuel. Sludge in the bot-tom third is discarded before refilling. The tanksmust be housed in a heated building, and each fit-ted with heating coils. Immediately after filling,hot water is circulated through the heating coiluntil the tank is heated to 100°F (38°C). The heatis then shut off and the fuel allowed to settleundisturbed for four days. During this time, fuelis being used from a second tank. Temperatureinside the settling tank building should be main-tained above 70°F (21°C), and the tanks mustbe vented outside the building.

A two-day supply of diesel fuel should be main-tained for emergency use and to start and stopengine when the crude fuel is highly viscous orheavy with paraffins.

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Figure 9.9

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Exhaust systems collect exhaust gases fromengine cylinders and discharge them as quicklyand silently as possible. A primary design con-sideration of the exhaust system is to minimizebackpressure. Backpressure will indirectly raisethe exhaust temperature which will reduce exhaustvalve and turbocharger life. A well designedexhaust system will have minimum backpressure.

All internal combustion engines generate heat asa result of combustion. The temperatures inCaterpillar engines combustion chambers canreach 3,500°F (1927°C). 30% of this total heatis expelled through exhaust.

For safety reasons an exhaust system must begas tight. It should also be insulated, shielded, orisolated to avoid damage, injury, or distress fromexposure to, or contact with, its high tempera-tures. Uninsulated exhausts greatly increase theheat rejection into an enclosed engine room. Toprevent excessive engine room temperatures, theexhaust system should be properly insulated.

CAUTION: Dry exhaust manifolds may requireguards when the work space makes it easier fora person to fall against the exhaust system.OSHA and other government bodies may haveregulations concerning this. The user is respon-sible to provide such guards where required butnot factory supplied.

Flexible Connections

The exhaust pipe must be isolated from theengine with flexible connections, Figure 10.1.They should be installed as close to the engine’sexhaust outlet as possible. A flexible exhaust con-nection has three primary functions:

1. isolate the weight of the exhaust piping fromthe engine. No more than 60 lbs (28 kg) ofexhaust piping weight should be supportedby 3400 and 3500 Series engines. The limitis 25 lbs. (11.3 kg) on smaller engines.

2. relieve exhaust components of excessivevibrational fatigue stresses;

3. allow for relative shifting between referencepoints on engine exhaust components. Thisshifting has numerous causes. It may resultfrom expansion and contraction of compo-nents due to temperature changes or by slowbut continual creep processes that take placethroughout the life of any structure.

In order to take care of vibratory stresses, soft-ness or flexibility of the flexible connection is ofprime concern. The connector must have highfatigue life to withstand normal stresses for indef-inite periods. Softness prevents transmission ofvibration beyond the connection. Resistance tofatigue keeps it from breaking under vibratory orrecycling stresses.

Optional Caterpillar flexible exhaust couplingsmeet these requirements. See Figures 10.1 and10.5. See Figures 10.3 and 10.4 for installationlimitations for these flexible connections.

On land rigs, exhaust piping or muffler shouldnot be supported by brackets, etc., connected tothe engine, Figures 10.1, 10.5, 10.6.

Growth and shrinkage of the exhaust pipe mustbe planned, otherwise it will create excessiveloads on exhaust piping and supporting struc-ture. Long runs of dry exhaust pipes can be sub-jected to very severe stresses from expansionand contraction. From its cold state, a steelexhaust pipe will expand about 0.0076 inch perfoot of pipe for each 100°F rise of exhaust tem-perature (0.11 mm/m for each 100°C). Thisamounts to about 0.65 inch expansion for each10 feet of pipe from 100°F to 950°F (52 mm/mper meter from 35°C to 510°C).

It is of utmost importance that flexible pipe, wheninsulated, be insulated in such a way that the flex-ible pipe can expand and contract freely withinthe insulation. This generally requires either asoft material or an insulated sleeve to encase theflexible pipe.

Long runs of exhaust pipe should be divided intosections having expansion joints between sec-tions. Each section should be fixed at one end andbe allowed to expand at the other. Figure 10.7 illus-trates methods for connecting exhaust systems.

EXHAUST SYSTEM

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Installation Limits of Bellows-Type Flexible Exhaust FittingsA B C

Maximum Offset Maximum Compression Maximum ExtensionHose Between Flanges From Free Length From Free Length

Diameter in. mm in. mm in. mm8 & 12 in. 0.75 19.05 1.50 38.1 1.00 25.4014 in. 0.75 19.05 3.00 76.2 1.00 25.4018 in. 0.90 22.86 3.00 76.2 1.75 44.45

PROPER MUFFLER MOUNTING

Figure 10.1

Four (4) small straps can be tack-welded betweenthe two end flanges to hold the engine exhaustflexible connection in a rigid position duringexhaust piping installation. This will prevent thefitting from being installed in a flexed condition.Attach a warning tag to the fitting noting that the

weld straps must be removed prior to starting theengine.

For maximum durability, allow the flexible con-nection to operate as close as possible to its freestate.

Figure 10.2

Flanges must be parallel

Free length

L

A

B or C

L = 457 (457 mm I.D.)

Installation Limits of Flexible Metal Hose-Type Exhaust FittingsA B C

Maximum Offset Maximum Compression Maximum ExtensionHose Between Flanges From Free Length From Free Length

Diameter in. mm in. mm in. mm4 & 5 in. 1.0 25.4 0.25 6.25 0.25 6.256 in. 1.5 38.1 0.25 6.25 0.25 6.25

Figure 10.3. Installation limits for bellows and flexible connections.

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Figure 10.4. Spring rates.

Piping

Physical characteristics of the equipment room onoffshore rigs determine exhaust system layouts.Arrangements with minimum backpressures arefavored. Securely support pipes and rubberdampers or springs installed in the exhaust pipebracing to isolate vibrations.

Piping must be designed with engine service inmind. In many cases, an overhead crane will beused to service the heavier engine components.

For both installation economy and operating effi-ciency, engine location should make the exhaustpiping as short as possible with minimum bendsand restrictions. There should be a sleeve in wallopenings to absorb vibration and an expansionjoint(s) in the pipe to compensate for lengthwaysthermal expansion or contraction.

Install piping with 9 in. (229 mm) minimum clear-ance from combustible materials.

Exhaust heat must be discharged without caus-ing discomfort to personnel or hazards to struc-tures or equipment.

Extend exhaust stacks to avoid heat, fumes andodors. Also, the exhaust pipes should not be inclose proximity to the air intake system forthe engine or the crankcase ventilation system.Engine air cleaners, turbochargers, and after-coolers clogged with exhaust products can causepremature failures. Pipe outlets cut at 30° to 45°angles will reduce gas turbulence and noise. Raincaps forced open by exhaust pressure will keepwater from entering.

Muffler placement greatly affects silencing abil-ity. See Figure 10.8. Locating it near the engineminimizes transmission of sound to the exhaustpiping. Higher exhaust temperatures near theengine also reduces carbon buildup in the muf-fler; a drain removes condensation.

During repowers, engine hp may be increased.Larger mufflers and/or piping may be required.Avoid sudden changes in diameter if existingexhaust piping is retained. These act as orificesand their pressure drop is hard to predict, but canbe very high.

Spring Rate forBellows-Type Flexible Fittings

Spring Rate — AxialDiameter lb/in. kN/m

8 in. 170 29.712 in. 194 33.914 in. 391 68.518 in. 110 19.3

EXHAUST SYSTEMFigure 10.5

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EXHAUST SYSTEMFigure 10.6

1. Engine exhaust outlet. 6. Anchor point for vertical run of pipe.2. Flexible pipe connection. 6.

NOTE: Allowance for expansion must be made on either side of 3. Long sweep elbow. 6.

anchor. If muffler is used, it should be installed as section of pipe.4. Longitudinal and lateral pipe support, fixing location of end pipe.5. Lateral pipe support, allowing for longitudinal expansion. 7. Expansion sleeve with spray shield.

8. Condensate trap (removable for cleanout).

Figure 10.7

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Mufflers

For muffler location instructions see Figure 10.8.

Exhaust noise attenuation is best performed witha quality muffler; however, attenuation charac-teristics of a muffler are not the same for all fre-quencies. Therefore, the effect of a given mufflerupon a naturally aspirated or a turbochargedengine could be different. The effect of a givenmuffler could be quite different if the engine runsat two different speeds.The manufacturer mustbe contacted for any specific muffling charac-teristics. As an additional noise attenuation aid,the exit opening of the exhaust pipe should be cutat a 30° angle (0.52 rad), Figures 10.5 and 10.6.

Consult the TMI for engine exhaust noise data.

Figure 10.8

Spark arresting mufflers are available. These aremany times specified when the owner judgesthem to be beneficial.

Mufflers are rated according to their degree ofsilencing and commonly referred to by such termsas “residential” or “critical” and “supercritical”.

• “Residential” — Suitable for industrial areaswhere background noise level is relativelyhigh or for remote areas where partly mufflednoise is permissible.

• “Critical” — Reduces exhaust noise to anacceptable level in localities where moderately

effective silencing is required — such assemi-residential areas where a moderatebackground noise is always present.

• “Supercritical” — Provides maximum silenc-ing for residential, hospital, school, hotel,store, apartment building and other areaswhere background noise level is low and gen-erator set noise must be kept to a minimum.

At least 5 diameters of straight pipe upstream ofthe muffler and 2.5 diameters downstream arerequired to minimize turbulence and backpressure.

Piping

Combined engine exhaust systems can allowoperating engines to force exhaust gases intoengines which are not operating. This is not anacceptable installation practice.

Recirculated exhaust gas will cause several prob-lems. Gas will condense an appreciable amountof water which can cause engine damage. Also,soot can clog the turbocharger, aftercooler, orplug air cleaner elements.

Use of an exhaust isolating valve has not beensuccessful. Deterioration at exhaust temperaturestends to be high plus soot buildup causes thevalve to leak. If the valve is not gas tight, it isineffective.

Check that generator power and control cablesare not mounted too close to the exhaust.

When moving a land-rig engine, exhaust outletsshould face opposite forward movement. If headedforward, the turbocharger could rotate from theair forced into it, resulting in engine failure shortlyafter spudding the next well.

Rain Protection

The exhaust end should be sloped and the pipeend angled to prevent water entering the pipe.Alternatively, some form of rain cap should befitted to the vertical exhaust system.

Cleanliness

Install an identifiable blanking plate to preventdebris from falling into the turbocharger duringinstallation. The Caterpillar shipping cover canbe used for this purpose. Install it directly on topof the turbine housing. Attach a warning tag tothe plate indicating it must be removed prior tostarting the engine.

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Slobber

Extended engine operation at no load or lightlyloaded conditions (less than 15% load) mayresult in exhaust manifold slobber. Exhaust man-ifold slobber is the black oily fluid than can leakfrom exhaust system joints. The presence ofexhaust manifold slobber does not necessarilyindicate an engine problem. Engines are designedto operate at loaded conditions.

At no load or lightly loaded conditions, the seal-ing capability function of some integral enginecomponents may be adversely affected. Exhaustmanifold slobber is not usually harmful to theengine; the results can be unsightly and objec-tionable in some cases.

Exhaust manifold slobber consists of fuel and/oroil mixed with soot from the inside of the exhaustmanifold. Common sources of oil slobber areworn valve guides, worn piston rings, worn turbo-charger seals or light load poor combustion. Fuelslobber usually occurs with combustion problems.

A normally operating engine should be expectedto run for at least one hour at light loads withoutsignificant slobber. Some engines may run for aslong as three, four or more hours before slob-bering. However, all engines will eventually slob-ber if run at light loads. External signs of slobberwill be evident unless the exhaust system is com-pletely sealed.

If extended idle or slight load periods of engineoperation are mandatory, the objectionable effectof the engine slobber can be avoided by loadingthe engine to at least 30% load for approximatelyten minutes every four hours. This will removeany fluids that have accumulated in the exhaustmanifold. To minimize exhaust manifold slobber,it is important that the engine is correctly sized foreach application.

Exhaust Gas Recirculation

Exhaust stacks must be designed so engineexhaust is discharged high enough and in a direc-tion to keep it clear of air turbulence and eddycurrents created by wind, radiators, and the rig’sfresh air supply system. Engine air cleaners, tur-bochargers, and aftercoolers clogged withexhaust products will cause engine failures,Figures 10.5 and 10.6.

Exhaust Backpressure

Backpressure limits recommended are 27 in.(685 mm and 6.7 kPa) of water for turbochargedengines and 34 in. (865 mm and 8.5 kPa) ofwater for naturally aspirated engines, measuredat the fitting in the exhaust elbow provided forthis purpose. There is no minimum backpressurerequirement.

To avoid excessive exhaust temperature, loss ofpower, increased fuel consumption, and sootfrom incomplete combustion caused by back-pressure, a method of approximating the back-pressure of the system in the design phase isprovided. (See Exhaust Backpressure Calcula-tion Worksheet, Figure 10.10). Figure 10.9 con-tains the data required to calculate exhaustbackpressure. The chart is calculated with anexhaust temperature of 900°F (482°C). Thisshould be increased/decreased 7% for every100°F/55°C increase/decrease from 900°F(482°C).

To ensure the above limits are not exceeded dur-ing operation, it is recommended the design limitbe one-half of the above backpressure limits.

Pressure drop includes losses due to piping, muf-fler, and rain cap, and is measured in a straightlength of pipe 3 to 5 diameters from the last tran-sition change after the turbocharger outlet. Thebackpressure should be measured as close to theengine as possible.

157 LEBW1414-00

Figure 10.9

2,000 (3320)

4,000 (6640)

6,000 (9960)

8,000 (13 280)

10,000 (16 660)

12,000 (19 920)

0

.04 (1)

.08 (2)

PR

ES

SU

RE

DR

OP

PE

R F

OO

T (

ME

TE

R)

OF

ST

RA

IGH

T P

IPE

AT

900

°F (

482°

C)

EXHAUST FLOW (CFM/m3•H) NOTE: With 800°F (427°C), pressure drop increases 7%.

16" (400 mm) dia14" (350 mm) dia12" (3

00 mm) dia

10" (

250

mm

) dia

8" (2

00 m

m) d

ia

6" (

150

mm

) di

a

5" (

125

mm

) di

a

4" (

100

mm

) di

a

LEBW1414-00 158

EXHAUST BACKPRESSURE CALCULATION WORKSHEET

General Data

Calculation for Backpressure:

I. Straight Pipe Resistance

Total Length of StraightSections of Exhaust Pipe Pressure Drop Resistance

_______________ ft. (m) X ➀ _______________ inch H2O/ft = ➁ _______________ inch of H2O✿______________ (mm H2O/m) ✿______________ (mm of H2O)

II. Elbow Resistance

Inside Diameter of Elbows Quantity of Elbows Equivalent Length

____________ in. (mm) X _________ std. 90° X 2.75 (0.033) = _____ ft. (mm)

____________ in. (mm) X _________ long sweep 90° X 1.67 (0.02) = _____ ft. (mm)

____________ in. (mm) X _________ 45° elbow X 1.25 (0.015) = _____ ft. (mm)

____________ in. (mm) X _________ square elbow X 5.50 (0.066) = _____ ft. (mm)

Total Equivalent Length _____________________ ft. (mm)

Pressure Drop Total Equivalent Length Resistance

➀ _______________ inch H2O/ft X _______________ ft. (m) = ➂ _______________ inch of H2O✿______________ (mm H2O/m) ✿______________ (mm of H2O)

III. Muffler Resistance

Obtain from manufacturer; based on muffler data and exhaust Resistanceflow data. ➃ _______________ inch of H2O

✿______________ (mm of H2O)

IV. Total Exhaust System Resistance

Straight Pipe Resistance Elbow Resistance Muffler Resistance System Resistance

➁ ––––––––– + ➂ ––––––––– + ➃ ––––––––– = ––––––––– inch of H2O*––––––––– (mm of H2O)

NOTE: Use additional pages for each pipe size. *kPa = inch of H2O X 0.249

Figure 10.10

Engine Model __________________________________

Power: ________________ HP @ _____________ RPM

PIPE DATA

Exh. Pipe Inside Diameter _______________ in. (mm)Pressure Drop ➀ ____________________ inch H2O/ft

(mm H2O/m)(See Figure 9.9)

EXHAUST FLOW DATA

__________________________________ CFM (m3/HR)

________________________________ lbs/min (kg/min)

__________________________________ °F (°C) Stack(See TMI or Engine Performance book)

MUFFLER DATA

Manufacturer _________________________________Model _____________________________________

Muffler Pipe ConnectionSize _________________________________ in. (mm)

159 LEBW1414-00

Engine Room VentilationEngine room ventilation must accomplish twothings:

1. Provide an environment which permits themachinery and equipment to function prop-erly with dependable service life.

2. Provide an environment in which person-nel can work comfortably and, therefore,effectively.

An engine not enclosed does not present venti-lation problems; therefore, this discussion appliesto engine rooms only.

About five percent of fuel consumed by an engineis lost as heat radiated to the surrounding air. Inaddition, heat from generator inefficiencies andexhaust piping can easily equal engine radiatedheat. Any resulting elevated temperatures inthe engine room may adversely affect mainte-nance personnel, switchgear, and generator setperformance.

General InformationThere are three aspects to ventilation:

Ventilation Air

The flow of air required to carry away the radiatedheat of the engine(s) and other engine roommachinery.

Combustion Air

The flow of air required to burn the fuel in theengine.

Crankcase Fumes Disposal

The crankcase fumes of the engine must beeither ingested by the engine or piped out of theengine room.

Engine Room TemperatureA properly designed engine room ventilation sys-tem will maintain engine room air temperatureswithin 15°F (9°C) above the ambient air tem-perature (ambient air temperature refers to theair temperature surrounding the vessel). In gen-eral, engine room temperature should not exceed120°F (49°C).

Offshore Rig VentilationIn modern offshore installations, natural draft ven-tilation is too bulky for practical consideration.Adequate quantities of fresh air are best suppliedby powered (fan-assisted) systems.

Correct routing of ventilation air is vital. Withoutit, air flow will not adequately maintain comfort-able engine room temperatures.

All engine room radiated heat is eventuallyabsorbed by engine room surfaces. Some istransferred to the air or water through the enclo-sure. The remainder must be carried away by aflow of cool ventilating air which picks up the heatthrough contact with these surfaces.

Ventilating systems must be designed to providesafe working temperatures and adequate air flowfor machinery, equipment, and personnel at alltimes, but especially when the rig’s hatches areclosed for bad weather operations.

For personal comfort, air movement of at leastfive feet per second should be maintained inworking area adjacent to sources of heat or whereair temperature exceeds 100°F (38°C).

Long runs of hot, uninsulated exhaust pipe candissipate more heat into an engine room than allmachinery surfaces combined. It is, therefore,important to completely insulate the exhaust sys-tem within the engine room’s work area. Hotpipes and other hot surfaces within the engineroom should also be insulated if localized highair temperatures are created because of them.

CAUTION: When refrigeration equipment isinstalled within engine room space, ensure itslocation is such that any refrigerant leakage willnot be drawn into the engine’s combustion air.Severe engine damage will occur if refrigerants,such as Freon or ammonia, get drawn into theengine’s air intake system. Locating refrigerantcompressors near an engine room air dischargearea is appropriate.

Offshore Rig Ventilation Systems

Recommended ventilating systems are describedbelow:

1. Bring outside air into the engine room througha system of ducts. These ducts should berouted between engines, at floor level, and

AIR INTAKE SYSTEMS

LEBW1414-00 160

discharge air up at the engines and genera-tors. The most economical method is to usethe service platform built up around theengines as the top of this duct, Figure 11.1 —Type 1.

This requires the service platform to be con-structed of solid, nonskid plate rather thanperforated or expanded grating. The ductoutlet will be the clearance between the deck-ing and oilfield base.

Ventilation air discharge fans should bemounted or ducted at the highest point in theengine room. They should be directly overheat sources.

This system provides the best ventilation withthe least amount of air required. In addition,the upward flow of air around the engineserves as a shield which minimizes theamount of heat released into the engineroom. Air temperature in the air dischargeduct will be higher than engine room airtemperature.

If System No. 1 is not feasible, the followingmethod is recommended:

2. Bring outside air into the engine room as faraway as practical from heat sources, utiliz-ing fans or large intake ducts. Discharge thisair into the engine room as low as possible,Figure 11.2 — Type 2.

Allow air to flow across the engine room fromthe cool air entry point(s) toward sources ofengine heat such as the engine, exposedexhaust components, generators, or otherlarge sources of heat.

Ventilation air discharge fans should bemounted or ducted at the highest point in theengine room. They should be directly overheat sources.

Engine heat will be dissipated with this sys-tem, but a certain amount of heat will stillradiate and heat up all adjacent engine roomsurfaces.

If the air is not properly routed, it will rise tothe ceiling before it gets to the engines,Figures 11.3 A and B.

This system will work only where the air inletscirculate the air between the engines. Airinlets located at the end of the engine roomwill provide adequate ventilation to only theengine closest to the inlet. Figure 11.3 Bshows this incorrect system.

3. If System 1 or 2 is not feasible, the followingmethod can be used; however, it provides theleast efficient ventilation.

Bring outside air into the engine room anddischarge it directly down on the engines withinlet fans, Figure 11.4 — Type 3.

VENTILATION TYPE 1Figure 11.1

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Ventilation exhaust fans should be mountedor ducted from the corners of the engine room.

This system mixes the hottest air in theengine room with the incoming cool air, rais-ing the temperature of all air in the engine

room. It also interferes with the natural con-vection flow of hot air rising to exhaust fans.Engine rooms can be ventilated this way, butit requires extra large capacity ventilating fans.

VENTILATION TYPE 2Figure 11.2

INCORRECT VENTILATIONFigure 11.3A

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INCORRECT AIR FLOWFigure 11.3B

Air Quantity Required for VentilationA method of calculating the quantity of airneeded to reach any predetermined temperaturein the engine room is determined by the follow-ing formulas:

It is recommended the engine room temperatureshould generally be less than 100°F (38°C).Engine room work area’s temperature should not

exceed 120°F (49°C). Where ambient tempera-tures exceed these values, Tr should be main-tained at 15°F (9°C).

1. For use with ventilating flow System 1,Figure 11.1

C = + Ca (English)

C = + Ca (Metric)

C = cfm (m3/hr) ventilating air required

He = Engine heat (Btu/min or kW) releasedto engine room per engine at maximumdesired engine room temperature,Figure 11.5.

Ha = Auxiliary or driven equipment heat(Btu/min or kW) released to engineroom per each power module. If exactheat rejection data is not available,an estimated value is one-third ofthe engine heat rejection for eachgenerator.

W = Density (lbs/ft3 or kg/m3) of air at max-imum outside ambient temperature,Figure 11.6.

Tr = Maximum desired temperature rise (°For °C) from outside ambient tempera-ture to air temperature in engine room.

He + Ha

0.00168 WTr

He + Ha

1.4 WTrPOWER UNIT

POWER UNIT

POWER UNIT

NO AIRBETWEEN

ENGINE

VENTILATION TYPE 3Figure 11.4

163 LEBW1414-00

Ca = Combustion air requirements of engine,refer to TMI or Engine Performancebook.

2. For use with ventilating System 2, Figure 11.2

C = + Ca (English)

C = + Ca (Metric)

3. For use with ventilating System 3, Figure 11.4

C = + Ca (English)

C = + Ca (Metric)

Radiator Cooled Engines

Engine driven blower fans on Caterpillar radiatorshave an air flow in excess of that required forengine room ventilation.

Radiator cooling fans are sensitive to air flowrestriction. Restriction in either inlet or outlet duct-ing should generally be less than 0.5 in. H2O(0.13 kPa). The radiator supplier should be con-tacted for the exact value.

Emergency/Standby Generator Set Ventilation

Emergency/Standby generator sets are normallyradiator cooled. The following additional guide-lines should be followed:

Radiator air inlet and outlet ports should each beat least 1.25 times the radiator frontal area.Resistance of louvers should be considered whencalculating air flow restriction on the radiator fan.Additionally, these ports must be so arranged ordeflected so air recirculation does not occur. Theengine exhaust outlet must be arranged soexhaust gas does not recirculate into the radia-tor air inlet.

If ventilation ports of the engine room are coveredby watertight doors, it is recommended the engineair cleaner be ducted outside of the engine room.Otherwise, starting of the engine with the doorsclosed will result in a vacuum in the engine room.

Total duct air flow restriction, including air clean-ers, should not exceed 10 in. (2.49 kPa) of watermeasured while the engine is producing full ratedpower. It is good design practice to design com-bustion air ducts to give the lowest practical restric-tion to air flow, since this will result in longer timesbetween filter element service or replacement.

He + Ha

0.00048 WTr

He + Ha

0.4 WTr

He + Ha

0.00084 WTr

He + Ha

0.7 WTr

Figure 11.5

Figure 11.6

Density of Air at Various Temperatures°F/°C lb./cu. ft. (kg/m 3) °F (°C) lb./cu. ft. (kg/m 3)0/–18 0.086 (1.38) 70 (21) 0.075 (1.20)10/–12 0.084 (1.35) 80 (27) 0.074 (1.18)20/–7 0.083 (1.33) 90 (32) 0.072 (1.15)30/–1 0.081 (1.30) 100 (38) 0.071 (1.14)40/4 0.079 (1.27) 110 (43) 0.070 (1.12)50/10 0.078 (1.25) 120 (49) 0.068 (1.09)60/16 0.076 (1.22) 130 (54) 0.067 (1.07)

Heat Rejection to AtmosphereBtu/min. (kW) Rejection at Various Engine Room Ambient Temperatures

Consult TMI for Actual ValuesEngine Model 85°F/29°C 100°F/38°C 115°F/46°C

3304 910 (16) 775 (14) 637 (11)3306 1375 (24) 1170 (21) 963 (17)3406 2100 (37) 1785 (31) 1470 (26)3408 3900 (68) 3300 (58) 2730 (48)3412 4200 (73) 3570 (62) 2940 (51)3508 5100 (90) 4350 (77) 3600 (63)3512 7690 (135) 6550 (115) 5390 (95)3516 10,200 (180) 8660 (152) 7100 (125)

LEBW1414-00 164

Combustion air duct velocity should not exceed2,000 ft./min. (610 m/min). Higher velocities willcause unacceptable noise levels and excessiveflow restriction.

EMERGENCY GEN SET ORPRODUCTION POWER HOUSE

Figure 11.7

Land SCR Rig Ventilation SystemsLand SCR rig engines equipped with suction orblower fan radiators have an air flow in excess ofthat required for recommended engine ventila-tion. As long as radiator air flow is not obstructed,no further ventilation requirements are needed.

Land rig engine installations with remote radia-tors or vertical discharge radiators should beinspected to determine if sufficient engine ven-tilation is provided.

Figure 11.8 illustrates a land rig installation whereventilation should be considered. Natural draftventilation is almost completely blocked by roofs,SCR house, tool room, and vertical discharge radi-ators. Warm weather operation may result in unac-ceptable engine and generator temperatures.

LAND RIG ENGINES REQUIRING VENTILATION

Figure 11.8

Figure 11.9 shows an engine room designed toprovide a combination of ventilation and engine/generator air inlet ducting.

Ventilation is provided by the air discharged fromthe generator. In warm weather, the air sourcevalve is positioned to provide outside air to thegenerator ventilation air inlet. Air discharged fromthe generator exits through the roof vent doorand open rear of base, providing engine ventila-tion as a secondary result.

Figure 11.9

165 LEBW1414-00

In cold weather, the air source valve will be posi-tioned to provide partial or total generator venti-lation air from within engine room.

If doors are added to rear of base, make sure thattotal enclosure is not airtight. This prevents pres-surizing engine room (reducing generator venti-lation air flow) when doors are closed and airsource valve is positioned to provide outside airto generator.

An air duct size of 2.0 sq. ft. (0.19 m2) is ade-quate for 3508, 3512, and 3516’s on up to 40 ft.(12.2 m) bases. The ducting to the air cleanersfrom air source valve can match the sizes of theoptional air cleaner inlet rectangular adapters.

Combustion Air IntakeA diesel engine uses large quantities of air forcombustion and requires that air enter its intakesystem with minimum restriction. Normal require-ments for combustion will fall very close to2.5 cfm (0.07 m3/min) per bhp for a CaterpillarDiesel Engine. High intake air temperature orhigh intake restriction raises engine exhaust tem-perature. Engine damage may result.

The air cleaner service indicator is actuated whenthe restriction reaches 30 in. H2O (762 mm and7.5 kPa). Above this value, engine performancebegins to be noticeably affected. This restrictionalso includes any air inlet piping pressure drop.Thus, air inlet duct restriction should be held toa minimum to prevent undue shortening of the aircleaner service intervals. An air intake ductrestriction of less than 3 in. (76 mm and 0.75 kPa)H2O is suggested.

Air entering the engine air cleaners should notbe more than 10°F (5.6°C) above ambient airtemperature. If it is not practical to design theengine room ventilation system to allow air with10°F (5.6°C) or less temperature rise to reachengine air intakes directly, it is advisable to runducts from air cleaners to points where fresh, coolair enters the engine room.

Combustion air inlet ducting, if used, should beso placed that it is in the path of the cool airinflow. It should not be directly in front of the airintake ducts or close enough to allow salt sprayor mist entering the engine room to enter engineintake ducts. Presence of salt in the intake air candamage an engine. Its presence in any significantquantity should be carefully avoided.

Wire-reinforced, flexible hose must not be usedas ductwork since it is susceptible to abrasionand abuse.

Figures 11.10 and 11.11 suggest ways of arrang-ing air intakes to take full advantage of the engineroom’s ventilating system. The air inlet mustbe located so exhaust fumes do not enter theengine. These fumes cause premature pluggingof air cleaner elements and reduce combustionefficiency.

On land rigs, also see Section Land Rig Ventila-tion Systems.

Air CleanersThe standard Caterpillar petroleum enginearrangements include dry paper, element-typeair cleaners, Figure 2.10. (A dry paper elementis the only type air cleaner which may be used.)

Figure 11.10 Figure 10.11

ENGINE ROOM AIR FLOW1. Engine 5. Ventilating cold air vertical stack-type discharge2. Air cleaner with duct connection 6. Ventilating cold air peripheral slotted 3. Intake air duct 6. duct-type discharge4. Ventilating cold air intake 7. Engine intake air pickup

LEBW1414-00 166

Their filtration efficiency exceeds 99%, providinggood protection to the engine.

Pressure drop across a typical air cleaner will be6.0 in. H2O (1.5 kPa) when clean. The on-enginepiping system might typically add another3.0 in. H2O (0.75 kPa) pressure drop.

Soot filters are included with electric drill rigengines. Soot filters extend the dry paper ele-ment life and reusability by catching the major-ity of oily, sooty deposits which would plug thedry paper element.

Heavy-duty air cleaners are recommended fordesert or dusty atmosphere, Figure 11.12. Heavy-duty air cleaners have a mechanical precleaningsection that lengthens the air cleaner life underdusty conditions. Check that the additional sizeof heavy-duty air cleaners do not cause physicalinterference with other equipment.

Heavy-duty air cleaners with exhaust-powereddust ejectors are available on 3400 Series andsmaller engines. No changes should be made toexhaust system, such as adding mufflers, becausethey reduce or nullify dust ejector efficiency.

Oil bath and oil-soaked screen-type air cleanersare not acceptable since filtration efficiency rarelyexceeds 95%. There is the constant danger ofimproper servicing resulting in even lower filtra-tion efficiency or oil carryover into the engine airintake system. Oil carryover causes aftercoolerplugging and possible turbocharger failure dueto increased exhaust temperatures.

Figure 11.12

CAUTION: Under no circumstances should theengines be operated without air cleaners.

The air inlet should be shielded against directentrance of rain or show. The most commonpractice is to provide a cap or inlet hood whichincorporates a coarse screen to keep out largeobjects. This cap should be designed to keep airflow restriction to a minimum. Some users havepiped to a front air intake location which gives adirect air inlet and an internal means of achiev-ing water separation.

Precleaners and prescreeners incorporated intothe intake cap design are also available. Theycan be used where special conditions prevail orto increase the air cleaner service life. Thesedevices can remove 70% to 80% of the dirt. Theprescreener is designed to protect the inlet sys-tem when trash is encountered.

Ducting for Remote Air Cleaners

Ducting: Ducting should be constructed offormed steel or aluminum tubing. Elbows maybe of these materials or molded rubber. Wherevibration could present a fatigue problem, hump-type connections of rubber or other flexible syn-thetic material must be used. The hump-type jointallows vibration isolation as well as minor mis-alignment due to manufacturing tolerances andengine or air cleaner movement.

Piping diameter should be equal to or larger thanthe air cleaner inlet and outlet and the engineair inlet. A rough guide for pipe size selectionwould be to keep maximum air velocity in thepiping in the 2,000 fpm to 3,000 fpm (10 m/s to15 m/s) range.

Consideration must be given to wall thickness ofmetallic components to ensure the clamp loadof rubber joints will not deform piping. Sealingsurfaces must be smooth to ensure proper fitand achieve a good airtight seal with matingparts. Fiberglass and molded plastic elbows areacceptable if they have sufficient strength toaccept clamping loads and provide airtight leakproof ducting.

Remote-Mounted Air Cleaners

Air Inlet: CAUTION: When air cleaners areremote-mounted and air is piped to the turbo-charger inlet, care must be taken to ensure airflow is introduced uniformly into the turbochargercompressor. Air striking the compressor wheel

167 LEBW1414-00

at an angle can result in pulsations causing pre-mature failure. Air flow must enter the turbo-charger through a smooth, straight pipe. Allowat least 2 in. of pipe (51 mm) between the pointof attachment to the turbocharger and the bendradius center point, Figure 11.13.

Figure 11.13

When fabricated elbows are required, they shouldbe constructed of sections not exceeding 15°(0.1745 rad) to allow a smooth flow of inlet air.To protect turbocharger components, care mustbe taken to remove all welding slag and splatterfrom the inside surface.

When rubber elbows or joints are used, theyshould always be double clamped. “T” bolt typeclamps providing 360° seal are recommendedbecause of their higher clamping load capability.

CAUTION: When using rubber or syntheticelbows or joints, review location to ensure thattemperatures do not exceed the capability ofthe material.

Where there is a width restriction, a plenumchamber can be fabricated as a space saver,Figure 11.14.

Figure 11.14

LEBW1414-00 168

Normal combustion pressures of an internal com-bustion engine cause a certain amount of blowbypast piston rings into the crankcase. To preventpressure buildup within the crankcase, vent tubesare provided to allow gas to escape.

Caterpillar does not recommend venting crank-case fumes into the engine room. Fumes will clogair filters and increase air inlet temperature withresulting engine damage. They can also causeproblems with electrical equipment.

Crankcase fumes should be discharged throughventing systems to atmosphere. A separate ventline for each engine is required.

Crankcase fumes vent pipes must be largeenough to minimize backpressure. If the equiv-alent length of straight pipe is equal to 20 ft.(6.1 m) or less, the size used for the fumes out-let on the engine will be satisfactory. For lengthsgreater than 20 ft. (6.1 m) use the next largersize pipe. As a general rule, the 3508, 3512, and3516 Engines require a 2 in. (50 mm) I.D.crankcase fumes disposal line. Over 100 ft. oflength (30.5 m), a 3 in. (75 mm) I.D. crankcasefumes disposal line is used.

Loops or low spots in a crankcase vent pipe mustbe avoided to prevent condensation in the pipeand restriction of normal discharge of fumes.Where horizontal runs are required, install the pipe

with a gradual slope from engine (1/2 in. per ft.[41.7 mm/m]), Figure 12.1.

All offshore rigs should have crankcase ventingsystems. Land rigs with engine driven blowerfans, generators driven off the front of the engine,or cold weather enclosures should also havecrankcase fumes venting systems, Figure 12.2.

Crankcase fumes must not be discharged intoair ventilating ducts or exhaust pipes. They willbecome coated with oily deposits creating a firehazard.

The crankcase pipe should vent directly to theatmosphere and be so directed that rain or spraycannot enter and run back into the engine.

Figure 12.2

CRANKCASE VENTILATION

Figure 12.1

169 LEBW1414-00

To minimize the amount of oil discharge throughthe vent pipe, a drip collector with drain may beinstalled near the engine, Figure 12.3.

Under no circumstances should crankcase pres-sure vary more than 1 in. (25.4 mm) of water fromambient barometric pressure. Higher crankcasepressures will tend to worsen any existing oilleaks. Measurement should be made with engineat 180°–200°F (68°–79°C) at engine dipstick.

Figure 12.3

LEBW1414-00 170

Figure 12.4 illustrates a powered fumes disposalsystem. The valves with each engine should beadjusted to provide no more than 1 in. (25.4 mm)of water column crankcase vacuum. Adjust valveswith only one engine operating. Fan capacity pro-vides a 4:1 dilution of fumes volume. A backupfan should be available.

A damper could be placed at the end of themanifold at the cleanout port and set to provide1 in. H2O (25.4 mm H2O) vacuum in enginecrankcase instead of bleed valve at each engine.

Figure 12.4

171 LEBW1414-00

DC drives are used on some older electric drillrigs. The following information is useful when con-sidering repowers on these rigs.

DC drives consist of an engine, DC generator,DC motor, and control equipment. Under certainconditions, the DC motor can become a gener-ator and drive the engine-driven generator as amotor, preventing safety shutoffs from stoppingthe engine. This can occur when two generatorsare paralleled on a drawworks motor or when two

engines are driving each of two motors on a mudpump or drawworks.

To protect against these possibilities, the enginemust be equipped with low oil pressure, highwater temperature, and overspeed switches con-nected to the DC control system generator exci-tation cutout section. One set of contactors issufficient regardless of the number of DC gener-ators driven per engine, Figure 13.1.

DC POWER SYSTEMS CONTROLS

Figure 13.1

HIGH WATERTEMPERATURE

LOW OILPRESSURE

LEBW1414-00 172

When tripping pipe in or out of the hole, regen-erative power surges can occur as the travelingblock nears the crown block. These power surgesdrive the generator and engine above the enginegoverned speed (overrun).

Regenerative power surges can cause nuisancetripping of the engine overspeed device. Overruncan be kept below the engine overspeed shutoffsetting by controlling the rate of drop-off of DCgenerator excitation. The rate of excitation drop-off should be spread over as much as five sec-onds to minimize this power surge.

It is recommended that a separate engine beoperated for each drawworks motor. This pro-vides more engine frictional hp to help resist thesepower surges during tripping.

To conserve fuel and increase engine life, thedriller’s console controls can be equipped to sig-nal the air actuated governor to return to lowspeed when the generators on that engine aren’tbeing used, Figure 13.2.

Figure 13.2

173 LEBW1414-00

The following items, normally supplied by oth-ers, are not all-inclusive but generally have aninfluence on engine operation.

Voltage Regulators

Operation characteristics of voltage regulatorsaffect engine performance when the AC loadsare dominant, such as jacking an offshore rig orduring load bank testing. The DC load controls(SCR modules) include DC excitation controlsthat are adjusted to match load application toengine capability.

Where the AC loads can be dominant, Caterpillarrecommends the volts-per-hertz type regulatorrather than the constant voltage type. When run-ning at rated speed, there is no difference in oper-ating characteristics of the two types of voltageregulators; however, during overload conditions,the constant voltage type tends to stall the enginewhile the volts-per-hertz regulator allows theengine to lug. Because of this characteristic, con-stant voltage regulators are sometimes referredto as hard regulators.

A hard regulator maintains constant voltage asgenerator frequency varies. When an engine issubject to an overload, it begins to slow down.Constant line voltage keeps the electrical loadabove the engine’s capability, and the enginegenerally will not recover. Thus, the constantvoltage regulator works against the engine andprevents engine recovery.

The volts-per-hertz regulator maintains a voltagelevel proportional to frequency. Thus, as theengine slows down due to an overload, reductionin generator voltage reduces electrical load. Thisassists engine recovery. An engine-generator setequipped with a volts-per-hertz regulator can alsopick up larger block loads with a smaller fre-quency dip.

Parallel operation requires the generators to beequipped with either a voltage droop or cross-current compensation system. A voltage droopsystem is standard on the optional Caterpillarvoltage regulators.

Voltage droop or cross-current compensationsystems must operate effectively, particularly onrectified drill rigs, with a very low power factor.Circulating current will proportionately reduce the

load sharing accuracy of the Woodward 2301Aelectric governor.

Electrical Instruments

Frequency meter: A dial-type meter is preferredfor accuracy of frequency readings below ratedspeed. Reed-type instruments are susceptible tofrequency harmonics.

Voltmeter: Where three or more generating unitsare in an installation, it is recommended only onevoltmeter per system be used. Individual gener-ators can be connected to this single meterthrough the synchroscope switch at the time ofparalleling. A single voltmeter minimizes metererrors. A voltmeter continuously monitoring thebus voltage should also be included.

Ammeter: No special requirements other than atleast one ammeter and a three-phase selectorswitch should be included per generator.

kW meter: A kW meter is recommended for par-allel operation involving either rectified systemsor larger generator sets.

PF meter (power factor): PF meters are recom-mended under certain conditions of parallel oper-ation; for example, where operating personnelfrequently adjusts generator controls. Tinkeringresults in generator misadjustment and subse-quent high ampere readings. When this happens,adjusting the generator controls until the amperesare rebalanced does not necessarily bring thegenerators back into balance.

With a PF meter, proper generator voltage adjust-ment procedure is as follows:

1. In single-unit operation, use volt meter to deter-mine proper generator voltage adjustment.

2. In parallel operation, use PF meter instead ofa voltmeter or ammeter because generatorvoltages are properly adjusted only when allunits show the same power factor.

KVAR meters perform the same function asPF meters. However, when the governors are notadjusted to carry the same kW load (or differentsize generating units are used), calculation isrequired to determine proper readings.

PF meters are also recommended for rectifiedpower systems.

AC POWER SYSTEMS CONTROLS

LEBW1414-00 174

Safety Considerations

Reverse Power Relay (RPR): This system isrequired for parallel operation. The RPR opensthe circuit breaker when generating units drawpower from the line rather than supplying powerto it.

Reverse power can occur due to improper gov-ernor settings or an engine safety shutoff signal.CAUTION: shutting off the fuel of an engine oper-ating in parallel does not stop it because the gen-erator becomes a motor as soon as it tries to runslower than other paralleled generators.

As a general rule, the RPR setting should be 6–8%of the generator kW rating. At this value, the timedelay should be less than two seconds. CaterpillarDiesel Engines require a larger amount to motor-ize at rated speed. Exact frictional horsepowerdata is available if required.

Setting the RPR for a lower activation point usu-ally causes nuisance trips when paralleling. Also,many Reverse Power Relays are really ReverseCurrent Relays, and, as such, their effective kWactivation point is reduced by any circulating cur-rent between generating units. In fact, with highcirculating current (caused by generator misad-justment), it is possible to have a reverse currenttrip while generating power.

kW overload protection on SCR rigs: Engines onAC rectified drill rigs must have some type of kWoverload protection. This protection should notopen the generator circuit breaker, but ratheroperate circuitry that reduces DC electrical load;otherwise, loss of one generating unit can resultin power outages due to underfrequency of theremaining generating units tripping their circuitbreakers.

Devices that sense kW loads above the engine-generator rating will not provide complete pro-tection. Although these devices would actuateduring a gradual overload, they cannot protectagainst a large sudden overload resulting from aparalleled generator set shutting down due to afault. Remaining generating units would beslowed down in rpm so fast that a kW overloadwould not be detected.

If other means of overload protection are not pro-vided, Caterpillar recommends that an underfre-quency sensor be connected to the switchgearbus. It should be set for 5 Hz below rated fre-quency and include a two-second time delay so

short transients will not actuate the system. Thisdevice should signal the load reduction system.

Disconnecting the AC load on an SCR drill rigusually does not remove an overload becausethe major electrical load is the SCR poweredequipment. Load reduction can be accomplishedby selectively “phasing-back” noncritical SCR-powered loads or by reducing the power outputsetting of all SCR-powered equipment.

Ampere overload protection: The ampere over-load device of the circuit breaker should be over-sized if the protection system is temperaturesensitive. Loose connections or high switchgearambient temperatures can cause premature trip-ping of temperature sensitive circuit breakers. Anoversizing of 15% is suggested. (Consult appli-cable electrical codes.)

Automatic tripping mechanism of the circuitbreaker: Breakers may be tripped electrically byeither a shunt trip or an undervoltage releasedevice. Caterpillar recommends the undervolt-age release on electrically operated circuit break-ers. A shunt trip will open the circuit breaker aslong as AC power is still available. If only oneengine is running and it stops due to a nonelec-trical fault, the circuit breaker will not open.(Reverse power has not occurred.) Damage toelectrical equipment can occur if another gener-ator is put on the line without first opening thiscircuit breaker.

Battery voltage alarm: Where electric governorsare used, the control battery should be protectedwith a low battery voltage alarm. Battery voltagelower than 22 volts on a 24 volt system can causegovernor instability or loss of power. (Do not usea battery which will have other high electricalloads — such as engine starting — as an elec-tric governor power supply.)

Paralleling check relay: Such relay preventsuntrained people from paralleling generators outof phase. Extensive electrical and/or mechanicaldamage can occur due to paralleling out of phase.

Emergency Generator Considerations

Automatic start-stop arrangements and crankingpanels are available for all Caterpillar Engines.The Caterpillar automatic start-stop group con-tains the electric starting motor(s), engine shutoffdevice, high water temperature and low oil pres-sure shutoff contactors (overspeed is available),

175 LEBW1414-00

and wiring of the above controls to a junction box(all mounted on the engine).

Caterpillar cranking panels are required with non-electronic engines and provide an electrical sig-nal to crank the engine, disconnect starter whenengine starts, and stops engine if a fault occurs orif the power outage is over (to be mounted by cus-tomer). Electronic engines contain this circuitry.

A cranking panel does not contain the AC powerfailure relay which determines when to start or stopthe engine automatically. This relay is usually apart of the customer’s automatic transfer switch.

Jacket water heaters are also available fromCaterpillar. They provide fast and reliable start-ing in ambient temperatures below 70°F (21°C).

Electrical equipment required to support opera-tion of the emergency generator set should bepowered off the emergency bus. This includessuch things as fuel transfer pumps, ventilatingfans, battery chargers and cooling pumps.

If an emergency stop control is on the driller’sconsole, the stop signal from this emergency stopcontrol must prevent the emergency generatorfrom starting as well as stop the main power plant.

The best method to assure the reliability of anemergency system is to periodically test theentire system. A simulated power failure shouldbe conducted monthly, with actual transfer switchoperation to connect the full emergency powerdemand to the generator set. The emergency sys-tem should function for one hour in the presenceof an authorized mechanic.

After completion of the run, the system should bereadied for automatic operation and rechecks offuel level and battery condition should be made.

Generator SizingSCR Drill Rigs

AC generators on SCR drill rigs frequently oper-ate at power factors less than 0.8. This can occurwhen DC motors operate at high DC amps andlow DC volts. This may occur when beginning tohoist (especially when the mud pumps are lefton), reaming the hole, low pump strokes, etc.

To allow engine capability to be more efficientlyutilized, generators should be specified with ahigh kVA rating. The SCR system supplier canprovide information on oversizing required with

a given SCR system. Caterpillar SR 4B Generatorsfor SCR service provide generous oversizing.

Approximate sizing for good performancerequires kVA equivalent to 0.6 PF. See the fol-lowing chart.

Generator kVA sizing (at 0.6 PF) for variousengine hp’s are shown below:

An undersized generator does not harm theengine — but the rig operation will require therunning of more engines than would otherwisebe required when low PF conditions are encoun-tered. This increases fuel consumption and putsunnecessary hours on the engines. While drillingthe larger diameter portions of the well, genera-tor limitations are usually not encountered.(During this time, the PF is near 0.8 PF becausethe mud pumps are operated quite fast — highpump strokes.)

Generator limitations are normally encounteredduring the deeper sections of the well. This iswhere the mud pumps are run at lower speeds(lower pump strokes) — with a resultant low PFon the generator. If the generator is not oversized,it will be necessary to run an extra engine in orderto provide sufficient generator capacity.

Drillers have also commented that oversize gen-erators improve the drawworks response. Manytimes, hoisting from the deep hole can be just asfast with one less engine running as comparedto engines with smaller generators. (The over-size generators allow the drawworks motors todevelop more torque, when the DC motors areat low speeds.)

(Many offshore rigs have propulsion machinerythat raises the total load to levels far greater thanthe drilling machinery alone requires. This propul-sion machinery typically operates at higher powerfactors. Combining these loads improves the

(D379) 610 hp 720 kVA(3508) 860 hp 1016 kVA(D398, 3508B) 912 hp 1075 kVA(3512) 1100 hp 1240 kVA(D399, 3512) 1215 hp 1435 kVA(D399, 3512, 3516) 1325 hp 1565 kVA(3512) 1435 hp 1695 kVA(3512B) 1476 hp 1743 kVA(3516) 1650 hp 1948 kVA(3516B) 1855 hp 2190 kVA(3516B HD) 2150 hp 2550 kVA

LEBW1414-00 176

system PF. Generators on these larger rigs there-fore may not be as oversize as shown above.)

AC Variable Frequency Drill Rigs

If the variable frequency drive is of the Diode frontend style, oversizing of the AC generator is notrequired. High kVA on the AC generator will notoccur. The special requirements for generatorconstruction to withstand voltage spikes and cur-rent stresses do still apply.

Generator Space Heaters

Generators must be kept clean and dry to provideacceptable service life. Generators can havewinding failures when shutdown in humid areas.

Space heaters are available for generators. Theyare installed within the generator and are to beenergized when the generator is not on-line torepel moisture. They must be connected to apower source. Caterpillar SCR generators havespace heaters as standard equipment. They arealso available for auxiliary or lite plant generators.

Serious consideration should be given to install-ing and using generator space heaters.

Generator Location

It is recommended that the rig layout place gen-erator sets as far as practical from mud tanksbecause some dust acts as a desiccant (attractsmoisture). Moisture and chemicals can causepremature generator failure. Drillers should con-sider wind direction when making a setup also.Generator space heaters should be consideredas an aid where moisture and dust cannot oth-erwise be controlled. NOTE: Heaters can onlyaid moisture control for a stand-by or at rest gen-erator.

Generators should be protected from direct rain.

177 LEBW1414-00

Instrumentation and control systems are an inte-gral part of the oilfield installation. Attention todesign, installation, and testing ensures a reliableinstallation that reduces maintenance costs.Suitable instrumentation enables the operator tomonitor oilfield engine systems and make cor-rections before failures occur.

Premium Oilfield Instrument Panel

This engine-mounted oilfield instrument panel,available on 3508, 3512, and 3516 engines,monitors five critical engine systems for non-elec-tronic engines, Figure 15.1. All instruments wereselected for reliability, durability and accuracyunder engine room environmental conditions.The panel offers calibrated mechanical gaugesplus a pyrometer and a self-contained electricaltachometer. It allows the operator to:

(1) Monitor essential systems for normal oper-ating conditions.

(2) Determine trends of changing conditionswhich could be due to deterioration of one ormore engine systems.

(3) Troubleshoot essential engine systems.

Periodic monitoring and recording of data, begin-ning with initial service, provides an engine his-tory. As normal engine operating conditionschange, preventive maintenance can eliminatepotential failures and downtime.

The operator can determine operating limits byreferring to the operating limit plate attached tothe instrument panel. These limits are based onthe engine running at oilfield continuous ratedspeed and load after warm-up and using SAE 30,API-CH-4, oil. At initial startup, gauge readingsshould be well within stated limits. If gauges reg-ister at or outside operating limits, any malfunc-tion or installation problem should be corrected.Information required to diagnose and correct anymalfunction or installation problem is containedin the Service Manual for each engine model.Routine operating instructions are contained inthe Operation Guide for each engine model.

3508, 3512, 3516

Figure 15.1

Premium Oilfield Instrument Panelsfor 3500B Engines

3500B engines incorporate both analog gaugesand digital readout of selected values.

The two modules included with every instrumentpanel are the main display module and gaugecluster module. The main display module con-trols all the instruments and gauge cluster mod-ule displays:

• Engine oil pressure

• Engine coolant temperature

• System voltage

• Engine fuel pressure

The second gauge cluster module displays:

• Right hand and left hand air inlet restriction

• Right hand and left hand exhaust temperature

• Fuel filter differential pressure

• Oil filter differential pressure

There is an option to add a third gauge clustermodule. The third gauge cluster module displays:

• Inlet air pressure (boost)

• Separate circuit aftercooler coolant tem-perature

• Engine oil temperature

• Inlet air temperature

The optional individual cylinder exhaust pyrom-eter group comes with the third gauge cluster.

STARTCONTROL &SHUTOFF OVERRIDE

OPERATING LIMIT PLATE

OILFIELD INSTRUMENTS

LEBW1414-00 178

InstrumentsFollowing is a description of the various standardand optional gauges.

Tachometer

The tachometer indicates engine rpm.

Jacket Water Temperature Gauge

This gauge indicates the temperature of thejacket water as it leaves the engine. Jacket watertemperature must be maintained between mini-mum and maximum limits.

Temperature gauge capillary tubes must berouted to avoid hot spots, such as manifolds orturbochargers, which will cause false readings.

Aftercooler Water Temperature Gauge

This gauge indicates the temperatures of thewater entering the aftercooler circuit. Emissionscompliant engines may monitor this.

Intake Manifold Air Temperature Gauge

This gauge indicates air temperature betweenthe aftercooler and the cylinder. The limits will

vary by engine rating. Jacket water aftercooledengines operate at a significantly higher inletmanifold air temperature than do separate cir-cuit cooled engines.

Exhaust Temperature Gauge (Pyrometer)

The pyrometer measures exhaust gas tempera-tures, normally after the turbocharger. On Veeengines with two turbochargers, a single instru-ment is supplied with dual temperature readoutfor both banks. On engines with single tur-bochargers, one instrument with a single read-out is provided. DO NOT USE EXHAUSTTEMPERATURE AS A LOAD SETTING INDI-CATOR WITH TURBOCHARGED AND TURBO-CHARGED/AFTERCOOLED ENGINES. Thepyrometer should be used only to monitorchanges in the combustion system and to warnof required maintenance.

The optional exhaust temperature gauge system,where available, adds the readings at each cylin-der exhaust outlet.

3500B ELECTRONIC INSTRUMENT PANEL

Figure 15.2

179 LEBW1414-00

Engine Oil Temperature Gauge

This gauge indicates oil temperature after thelube oil cooler. On most engines, the oil is cooledby engine jacket water. A high jacket water tem-perature or a clogged oil cooler will prevent theengine lube oil from being properly cooled.

Engine Oil Pressure Gauge

This gauge indicates the pressure of the filteredoil. Oil pressure will be greatest after starting acold engine and will decrease slightly as the oilwarms up. Oil pressure is greater at operatingspeeds than at low idle rpm. The specified min-imum oil pressure is for an engine running at con-tinuous rated speed. Plugged oil filter elementswill decrease engine oil pressure. The oil filterservice indicator (where provided) should bechecked regularly for premature filter plugging.STOP THE ENGINE IMMEDIATELY IF OIL PRES-SURE DROPS RAPIDLY.

Fuel Pressure Gauge

The fuel pressure gauge indicates the pressureof the filtered fuel. A power reduction will occurif the fuel pressure drops too low. Plugged fuelfilters decrease fuel pressure. High fuel pressurecan burst fuel filter housings, damage gaskets,and cause erratic speed control because ofincreased friction drag in injection pumps.

Air Restriction Gauge

The air restriction gauge measures the vacuumcaused by the air filter restriction. Clogged aircleaners will result in reduced air flow causinghigh exhaust temperature and sometimes exces-sive smoke. The air restriction gauge should bechecked regularly, and air filters should bechanged when restriction limits are reached.

Oil Filter Differential Gauge

This gauge measures the difference in pressurebetween the filtered and unfiltered sides of the oilfilter; a high reading will indicate plugged oil filters.Where supplied, this gauge should be checkedregularly.

Ammeter

Where supplied, an ammeter measures electri-cal current to or from the battery.

LEBW1414-00 180

Shutoffs

3508, 3512, and 3516 oilfield engines that arenon-electronic controlled are equipped with ahydramechanical low oil pressure, high watertemperature and overspeed shutoff. Shutdown isaccomplished by moving the fuel rack to shutoffposition.

The high water temperature shutoff will not pro-vide protection when the water level is below thesensing element.

These engines include an air inlet shutoff. Duringan overspeed or when the remote shutoff is actu-ated, this device shuts off the air inlet at the sametime the fuel rack is moved to the off position.This provides protection when operating in agaseous fuel atmosphere, Figure 16.1.

A monitoring gauge is included that will indicateshutoff is operable.

Remote shutoff provisions are also available. Aroutine shutoff option shuts only the fuel off. Theengine can then be restarted remotely after a sev-eral minute delay. An emergency shutoff optionshuts off both fuel and air. The air inlet shutoffmust be manually reset before the engine can berestarted.

Other Non-Electronic Engines

A mechanical shutoff is available for most otherengine configurations. It will automatically shutdown the engine is case of low oil pressure orhigh water temperature. This system is hydrauli-cally operated and contains a shutoff controlgroup which forces the engine fuel control toshutoff if an extreme limit is reached.

It may be necessary to manually override theshutoff when starting engine.

CAUTION: Sensing devices must not triggerengine shutdown in applications where engineprovides equipment mobility.

3508, 3512, 3516

Figure 16.1

Electronic Engine Shutoffs

Shutoff systems for electronic engines are incor-porated within the Engine Control Module (ECM).Shutoff of fuel is accomplished internally, and airinlet shutoff utilizes air inlet shutoff valves.

Compound DrivesFor compound drives, an engine oil pressureactuated 3-way valve may be added to discon-nect the air clutch from the compound. This pre-vents motoring of the engine by other engine(s)on the compound, Figure 16.2.

If air clutches are not used, this dump valve maybe used to actuate the torque converter or fluidcoupling dump valve. An air cylinder will also berequired, Figure 16.2.

The 3-way valve should be an Amot model4057-CE or equivalent. It will actuate on 20 psi(137.9 kPa) oil pressure and includes an emer-gency manual override in case engine is to bestarted through the compound. This will not beactivated by overspeed or the emergency shut-off button.

EMERGENCY SHUTOFFLOCAL REMOTE

MONITORGAUGE

SHUTOFFS AND ALARM SYSTEMS

181 LEBW1414-00

Alarm Contactors

Low oil pressure and high water temperaturealarms are most commonly used and are rec-ommended for every engine. These are presettemperature and pressure switches to be con-nected to the rig’s electrical system. They willactivate a customer-supplied audio or visualalarm when extreme temperature and pressurelimits are reached. Engines equipped with expan-sion tanks for heat exchanger cooling contain alow water level alarm switch.

Practically any additional engine function involv-ing speed, temperature, and pressure control canbe sensed at extreme limits by special alarm orshutoff systems. Extent of usage should dependentirely on the type and extent of monitoring andautomation desired.

Switches normally available from Caterpillar willoperate on AC or DC voltage from 6 volts to240 volts, Figure 16.3. See also section on DCPower Systems for alarm contactors required whendriving DC generators. These contactors (SPDTswitches) disconnect the generator’s excitation.

Figure 16.2

Contactor Switch Ratings

Figure 16.3

Alarm Panels

The most common type of user supplied alarmpanel contains alarm indicating lights for allengines. Caterpillar recommends the followingfeatures in alarm panels:

1. Fault light lock-in circuitry — keeps fault lighton when intermittent faults occur.

2. Lockout of additional alarm lights — preventssubsequent alarm lights from going on afterthe activated engine shutoff stops the engine.This aids in troubleshooting.

3. Alarm silence — allows engineman toacknowledge the alarm without having tocontinually listen to the alarm horn. Alarmlight is left on.

4. If more than one engine is connected to analarm panel, a fault in a second engine shouldactivate the alarm, even though the alarmhorn may have been silenced after a fault onanother engine.

5. Circuit Test — provides for periodic checkingof alarm panel functions.

Recommended Minimum Alarms

Radiator cooled engines:(Jacket water aftercooled)A. Low oil pressure — Figure 16.5B. High water temperature — Figure 16.4C. Overspeed — Figure 16.6

Heat exchanger or grid-cooler cooled engines:(Jacket water aftercooled)A. Low oil pressureB. High water temperatureC. OverspeedD. Low water level

Engines equipped with electric governors shouldhave a low control battery voltage alarm. A reversepower alarm or circuit breaker tripped alarmshould be considered on AC generating units. Alow sea water pressure alarm for the engine cool-ing systems should be included. If any otherengine room function is monitored, the fault indi-cator should be built into this control panel orlocated next to it.

World Class Contactors

Pressure and temperature contactors are avail-able. They meet the requirements of the marineclassification societies. They are adjustable,Figure 16.7.

TEMPERATURE CONTACTOR

Figure 16.4

Temperature Sensing

Rating with alarm or switch:

115-volt AC . . . . . . . . . . . . . . . . . . . 5A230-volt AC . . . . . . . . . . . . . . . . . . . 2.5A600-volt AC . . . . . . . . . . . . . . . . . . . 1A120-volt DC . . . . . . . . . . . . . . . . . . . .5A240-volt DC . . . . . . . . . . . . . . . . . . . .25 A48-volt DC . . . . . . . . . . . . . . . . . . . . 1.25A32-volt DC . . . . . . . . . . . . . . . . . . . . 1.9A24-volt DC . . . . . . . . . . . . . . . . . . . . 2.5A12-volt DC . . . . . . . . . . . . . . . . . . . . 5A

Pressure Sensing

Rating with alarm or switch:

125, 250, or 480-volt AC . . . . . . . . . 20A250-volt DC . . . . . . . . . . . . . . . . . . . 25A

Speed Sensing*

Rating with alarm or switch:

Mechanical Switch28-volt DC . . . . . . . . . . . . . . . . . . . . 5A115-volt DC . . . . . . . . . . . . . . . . . . . 1A120, 240, 480-volt AC . . . . . . . . . . . 10A125-volt DC . . . . . . . . . . . . . . . . . . . .5A

*Terminals are not under a cover.

Electronic Switch12-32-volt DC . . . . . . . . . . . . . . . . . 3A

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183 LEBW1414-00

PRESSURE CONTACTOR

Figure 16.5

OVERSPEED CONTACTOR

Figure 16.6

SOCIETY APPROVED CONTACTOR

Figure 16.7

WATER TEMPERATURE

OIL PRESSURE

LEBW1414-00 184

An engine starting system must be able to crankthe engine at sufficient speed for fuel combustionto begin normal firing and keep engine running.

These are two common types of engine startingsystems:

A. ElectricB. Air

Hydraulic starting is usable with Cat engines,but is not available from Caterpillar.

The choice of systems depends upon availabil-ity of the energy source, availability of space forstorage of energy, and ease of recharging theenergy banks.

Startability of a diesel engine is affected primar-ily by ambient temperature, lubricating oil vis-cosity, and size of the cranking system. The dieselrelies on the heat of compression to ignite fuel.This heat is a result of both the cranking speedand length of time for cranking. When the engineis cold, a longer period of cranking is required todevelop this ignition temperature.

Heavy oil imposes the greatest load on the crank-ing motor. Both the type of oil and temperaturecan drastically alter its viscosity. An SAE 30 oilwill, for example, approach the consistency ofgrease at temperatures below 32°F (0°C). Properengine oil viscosity should be provided accord-ing to recommendations in the engine operationmanual.

Electric StartingElectric starting is the most convenient to use.Storage of energy is compact, however, chargingthe system is slow and difficult in case of emer-gency. Electric starting becomes less effective astemperature drops due to loss of battery chargecapacity and an increase in an engine’s resistanceto cranking under those conditions. It is the leastexpensive system and is most adaptable to remotecontrol and automation, Figs. 17.1 and 17.2.

Do NOT crank the engine more than 30 seconds,or the starter will overheat.

Damage can result if water enters and is retainedin the starting motor solenoid. To prevent this,engines stored outside should be provided with aflywheel housing cover. If possible, the startingmotor should be mounted with the solenoid in anup position which would provide drainage andprevent water from collecting in the solenoid.

Engines which are subject to heavy driven loadduring cold start-up should be provided with aheavy-duty starting motor.

Batteries

Batteries provide sufficient power to crank engineslong and fast enough to start. Lead-acid typesare common, have high output capabilities, andlowest first cost. Nickel-cadmium batteries arecostly, but have long shelf life and require mini-mum maintenance. Nickel-cadmium types aredesigned for long life and may incorporate thickplates which decrease high discharge capability.Consult the battery supplier for specific recom-mendations.

Ambient temperatures drastically affect batteryperformance and charging efficiencies. Maintain90°F (32°C) maximum temperature to assurerated output. Impact of colder temperatures isdescribed, Figures 17.3 and 17.4.

Locate cranking batteries for easy visual inspec-tion and maintenance, away from flame or sparksources and isolated from vibration. Mount levelon nonconducting material and protect fromsplash and dirt. Use short slack cable lengths andminimize voltage drops by positioning batteriesnear the starting motor.

Charging Systems

Normally, engine-driven alternators are used forbattery charging. When selecting an alternator,give consideration to current draw of electricalaccessories to be used and to the conditions inwhich the alternator will be operating. An alter-nator must be chosen which has adequate capa-bility to power accessories and charge the battery.If the alternator will be operating in a dusty, dirtyenvironment, a heavy-duty alternator should beselected.

STARTING SYSTEMS

185 LEBW1414-00

Engine-driven alternators have the disadvantageof charging batteries only while the engine is run-ning. Trickle chargers are available but requirean AC power source. Battery chargers usingAC power sources must be capable of limitingpeak currents during the cranking cycle or musthave a relay to disconnect the battery charger dur-ing the cranking cycle. In applications where anengine-driven alternator and a battery tricklecharger are both used, the disconnect relay mustbe controlled to disconnect the trickle charger dur-ing cranking and running periods of the engine.

DIRECT INJECTION COMBUSTION SYSTEM

TYPICAL WIRING DIAGRAM (Mobile Equipment)

Figure 17.2

+–

ALTERNATOR

GAUGES, ETC.

LIGHTS, ETC.AMMETER

KEYSWITCH

MAGNETICSWITCH

STARTINGMOTOR

BATTERY

12V

DC DUAL STARTING SYSTEM

Figure 17.1

–

+BATTERY

STARTINGMOTORS

MAGSWITCH

OIL PRESSSWITCH

STARTSWITCH

Figure 17.3

Figure 17.4

Figure 17.5

Figure 17.6

NOTE: Use aids below 0°F (–18°C)

Suggested Minimum Battery Cold Cranking AmpsBattery Voltage 12 24-32 1-motor

Minimum °F –20 30 60 –20 0 603304 1450 1225 925 7253306 1450 1225 925 7253406 1225 9253408 1300 1225 9253412 1300 1225 9253508 1300 1225 925

Maximum Recommended Total Battery Cable LengthCable Size Direct Electric Starting

AWG MM2 12 Volt 24-32 VoltFeet Meters Feet Meters

0 50 4.0 1.22 15.0 4.5700 70 5.0 1.52 18.0 5.49000 95 6.0 1.83 21.0 6.400000 120 7.5 2.29 27.0 8.24

Temperature vs. Output°F (°C) % 80°F Ampere Hours Output Rating80 (27) 10032 (0) 650 (–18) 40

Battery PerformanceSpecific Gravity vs. Voltage

Sp. Gravity % Charge V per Cell Freezes °F (°C)1.260 100 2.10 –70 (–94)1.230 75 2.07 –39 (–56)1.200 50 2.04 –16 (–27)1.170 25 2.01 – 2 (–19)1.110 Discharged 1.95 +17 (–8)

LEBW1414-00 186

187 LEBW1414-00

Starting System Wiring

Power carrying capability and serviceability areprimary concerns of the wiring system.

Select starter and battery cable size, Figure 17.5.For correct size and correct circuit for startingsystem components, see typical wiring diagrams.Wiring should be protected by fuses or a manualreset circuit breaker (not shown on the wiringdiagrams). Fuses and circuit breakers shouldhave sufficient capacity and be readily accessi-ble for service.

Other preferred wiring practices are:

• Minimum number of connections, especiallywith battery cables.

• Positive mechanical connections.

• Permanently labeled or color-coded wires.

• Short cables to minimize voltage drop.

• Ground cable from battery to starter is pre-ferred. If frame connections are used, tinthe contact surface. Current path shouldnot include high resistance points such aspainted, bolted, or riveted joints.

• Protect battery cables from rubbing againstsharp or abrasive surfaces.

Air StartingAir starting, Figure 17.7, offers higher crankingspeeds than electric starting and is the most com-mon system used on drill rigs. It usually resultsin faster starts with less cranking time. Remotecontrols and automation are more complex andcumbersome. Storage of energy is bulky, butrecharging the system is relatively fast. Air forrecharging is always available. A small emergencyreceiver (not supplied by Caterpillar) can be handpumped to starting pressure under emergencyconditions or an auxiliary diesel engine-drivenair compressor package can be used. Systemrepairs can often be done on site with minimumtool requirement. Moisture condensation maytake place within the air system, causing inter-nal corrosion and freezing. Figures 17.8 and 17.9contain information required to size air startingsystems.

Recommended air pressure range is 90-150 psi(620-1034 kPa).

AIR STARTING SYSTEM WITH PRELUBE

Figure 17.7

LEBW1414-00 188

NOTE: Add to the 3516 1 cu. ft./sec. (0.0283 m3/s) of air consumption for the air operated oil prelubrication pump.This pump will normally operate 2 to 10 seconds before the engine begins to crank.

*Minimum air storage tank pressure required to sustain cranking at 100 rpm. Higher pressure required to initiate cranking.

Figure 17.8

Figure 17.9

Air Receiver Volume Required For One Second of Cranking TimeWith Pressure Drop From 250 to 125 psi (1724 to 862 kPa)

Engine Model cu. ft./sec. (m 3/s) Engine Model cu. ft./sec. (m 3/s)3304 0.535/0.0151 3508 1.42/0.04023306 0.506/0.0143 3512 1.33/0.0376

3516 1.30/0.03683406 0.518/0.01473408 1.90/0.0543412 1.82/0.051

Free Air Consumption f 3/s (m3/s)For a Bare Engine at 50°F (10°C)

100 psig 125 psig 150 psigEngine (690 kPa) (862 kPa) (1034 kPa) P min psig*Model To Starter To Starter To Starter (kPa)3304 5.8 (0.1641) 6.8 (0.1924) 7.7 (0.2179) 35 (242)3306 5.9 (0.1670) 6.9 (0.1953) 7.8 (0.2207) 36 (248)3406 6.2 (0.1755) 7.3 (0.2066) 8.3 (0.2349) 40 (276)3408 6.4 (0.1811) 7.5 (0.2122) 8.6 (0.2434) 39 (269)3412 9.0 (0.2601) 10.3 (0.2914) 11.8 (0.3339) 30 (207)3508 9.3 (0.26) 10.8 (0.30) 12.6 (0.36) 45 (310)3512 9.8 (0.28) 11.4 (0.32) 13.3 (0.38) 50 (344)3516 10.5 (0.30) 12.1 (0.34) 14.1 (0.40) 65 (448)

The air supply line between storage tank and airmotor should be short and direct, and of a sizeequal to the discharge opening of the air receiver.Black iron pipe is preferable and must be prop-erly supported to avoid vibration damage to thecompressor. Flexible connections between com-pressor outlet and piping are required.

The shipyard or rigup yard must thoroughly cleanthe air piping prior to first engine start. Rust ordebris can destroy the air starter.

Air storage tank should meet American Societyof Mechanical Engineers (ASME) — or other rec-ognized source of specifications — pressure ves-sel specifications and should be equipped with asafety valve and pressure gauge. Safety valvesshould be regularly checked to guard againstpossible malfunction. A drain cock must be pro-vided in the lowest part of the air receiver tankfor draining condensation.

Many applications require sizing air receivers toprovide a specified number of starts. This can beaccomplished using the following equation:

English System

Vt = Vs 2 T 2 14.7 psi__________________Pt – Pm

SI System

Vt = Vs 2 T 2 101 kPa__________________Pt – Pm

Vs = Starter air consumption (ft3/sec or m3/sec),Figure 17.8.

Vt = Air storage tank capacity (cubic feet orcubic meters)

Pt = Air storage tank pressure (psig or kPa)T = Cranking timePm = 90 psig (620 kPa) when sequential

crank cycles are used. Use P minimum,Figure 17.8, when a single crank cycle isused.

189 LEBW1414-00

The quantity of free air required per start (Vs)depends on three factors:

A. Cranking time required per start

Cranking time per start depends on enginemodel, engine condition, ambient air temper-ature, oil viscosity, fuel type, and design crank-ing speed. Five to seven seconds is typicalfor an engine at 80°F (26°C). Restarts of hotengines usually take less than two seconds.

B. Rate of free air consumption

Rate of free air consumption depends onthese same variables, and also on pressureregulator setting. Correct pressure regulatorsetting is 90 to 150 psi (620 to 1033 kPa),with the higher pressure used to improvestarting under adverse conditions. 5 to 15 ft3/s(0.14 to 0.42 m3/s) is typical for enginesfrom 50 to 1200 hp (37 to 895 kW).

C. Operation

The air supply must be shut off as soon asengine starts or the sensing system mustclose the solenoid air valve to prevent wast-ing starting air pressure.

Water vapor in the compressed air supply mayfreeze as air is expanded below 32°F (0°C). Adryer at the compressor outlet or a small quan-tity of alcohol in the starter tank is suggested.

This formula may be used to estimate the timerequired for an air compressor to raise the pres-sure in an air receiver to a specified limit:

T = Pt 2 R________Pa 2 N

T = Time in minutes

Pt = Final pressure of tank (psia or kPa)

Pa = Atmospheric pressure (psia or kPa)

R = Volume of air receiver (ft3 or m3)

N = Net free air delivery of compressor (ft3/minor m3/min)

Starting AidsThe diesel engine depends on heat of compres-sion of air in the cylinder to ignite fuel. Belowsome minimum temperature, even a reasonablysized cranking system will not turn the enginefast enough or long enough to ignite fuel without

one or more commonly used starting aids suchas jacket water heaters and/or ether.

Adequate starts can usually be obtained withproperly maintained systems above 60°F (15°C)ambient temperatures without aids.

Jacket water heaters maintain water at a tem-perature high enough to start engine. kW ratingof the jacket water heater depends on CoolingSystems — Jacket Water Heaters for additionaldetails.

Ether is a volatile and highly combustible agent.Small quantities of ether fumes added to theengine’s intake air during cranking reduce com-pression temperature required for engine start-ing. This method can be used for starting of anengine at practically any ambient temperature.Ether starting aids are available on the smallerCaterpillar engines.

CAUTION: When other than fully sealed ethersystems are used, ensure adequate ventilationfor venting fumes to the atmosphere to preventaccidental explosion and danger to operatingpersonnel.

The high pressure metallic capsule-type is rec-ommended for mobile applications. When placedin an injection device and pierced, ether passesinto the intake manifold. This has proven to bethe best system since few special precautions arerequired for handling, shipping, or storage.

Ether must be used only as directed by the man-ufacturer of the starting aid device. The ether sys-tem must be such that a maximum of 3.0 cc ofether will be released each time the button ispushed. Caterpillar ether systems are designedto release 2.25 cc of ether each time the systemis activated. Excessive injection of ether candamage an engine. Ether should not be releasedinto a running engine.

Lighter fuels, such as kerosene, can ease theunaided cranking requirements slightly by low-ering the compression temperature required forstarting. These lighter fuels also slightly reducehorsepower delivered at any given fuel rack setting.

Excessive parasitic loads should be disconnectedduring engine cranking.

Prelubrication Systems

If the 3516 engine is started or operated at lowidle until oil pressure is attained, prelubricationis NOT required.

The 3516 oilfield engine includes a prelubrica-tion system to provide lubricating oil to criticalcomponents before cranking and starting theengine. Caterpillar furnishes an air cranking/airprelubricating system, Figure 17.7 and 17.10.This consists of an air-driven prelubrication pumpthat draws oil from the engine sump and forcesit into the engine. This pump is driven by an airmotor which, through sequence valving, runsuntil a predetermined engine oil pressure shuts itoff and turns on the air cranking motor.

Oilfield engine applications that use the 2301AElectric Governor do not require prelubricationpumps because a properly wired 2301A Governormaintains engine speed at low idle speed untiladequate oil pressure is in the lube system. Whenthe engine starts and accelerates to low idle, itwill stay at that speed until an electric switch isclosed by engine oil pressure. The engine willthen accelerate to rated speed.

Any solenoids used in the starting system mustbe DC to ensure starting during an AC poweroutage.

Driven Load Reduction Devices

Effect of driven equipment loads during coldweather engine starting must be considered.Hydraulic pumps, air compressors, and othermechanically driven devices typically demandmore horsepower when they are extremely coldat start-up. The effect of this horsepower demandmay be overcome by providing a means ofdeclutching driven loads until the engine hasbeen started and warmed up for a few minutes.This is not always easy or practical, so othermeans of relieving the load at cold start-up maybe required if the engine-load combination can-not be started with sufficient ease using enginestarting aids described earlier.

Some air compressors provide for shutoff ofthe air compressor air inlet during cold starting.This greatly decreases drag on the engine andimproves cold startability. This approach can onlybe used when the air compressor manufacturerprovides this system and fully approves of its use.Otherwise, air compressor damage could result.

LEBW1414-00 190

Figure 17.10

AIR START AIR PRELUBE

191 LEBW1414-00

IntroductionElectrolytic and galvanic activity can cause seriousdamage to an engine. Troubleshooting requireshighly skilled personnel. The best procedure isto attempt to provide adequate safeguards forengines during rig construction. Troubleshootingis further complicated by the fact that damagedone by electrolytic or galvanic activity is usu-ally identical, but required solutions for eithercause usually aggravates the other.

Electrical systems should be so designed that nocontinuous electrical potential is imposed uponany cooling system components. Presence of anyelectrical potential may cause cooling systemmaterials to be damaged by electrolytic processes.

Galvanic activity in salt water circuits produces acorrosive action with metal, resulting in deteriora-tion of system components. Proper material selec-tion and cathodic protection should be employedby installing sacrificial zinc rods in sea water flowpassages at numerous locations. In order to main-tain this protection, zinc rods must be inspectedregularly and replaced when deteriorated.

Large amounts of electrical current are presenton offshore electric drilling rigs. Minute stray cur-rents should be minimized to protect engines.

DC and AC circuits should have insulated (float-ing) grounds.

The recommended floating circuit has no con-nection to ground and it can be described asinsulated from ground.

The two-wire circuit has an insulated return wirefrom the load to source as well as the lead wirefrom the source to load, Figure 18.1. Frames ofvarious electrical devices should be connectedto the hull if mounting of the device to the hulldoes not provide a sufficient ground.

Be aware that the ground between the hull and ametallic item resting on the hull can be weak-ened or destroyed by moisture, corrosion or poorarea of contact.

PLANNED ELECTRICAL SYSTEMS

Figure 18.1

S

G

LOAD+

–

A. SINGLE-WIRE GROUNDED (NOT RECOMMENDED)

S

G

LOAD+–

B. TWO-WIRE GROUNDED (NOT RECOMMENDED)

S

LOAD+–

C. TWO-WIRE FLOATING (RECOMMENDED)

S = SOURCE

ELECTROLYTIC AND GALVANIC ACTIVITY PROTECTION

LEBW1414-00 192

Metallic items in contact with the hull must bemade of metal similar to that of the hull metal.For example, a steel pump housing should be indirect contact with the hull in order to be groundedto the hull*. However, a dissimilar metal, such asbrass, should be isolated from the hull becausemoisture between the brass and hull will causegalvanic corrosion. The brass should be con-nected to the hull via a wire.

*Unless the types of steels have a significant volt-age potential difference (e.g. mild steel will cor-rode if it is coupled to stainless steel).

Because engines are in direct contact with thehull, the following procedure can be followed toassure that stray currents return to the powersource with minimal travel through metallic com-ponents, Figure 18.2.

The ground wire has a high resistance path backto the battery because of the insulating materialbetween the metallic plate and battery. This helpsminimize the amount of current flow.

Insulating material between the metallic placeand hull prevents stray currents from returningthrough the hull to the battery. These currentsmust return through the ground wire.

Figure 18.2

193 LEBW1414-00

Rapidly increasing fuel prices coupled withdecreasing fuel availability is receiving increasedattention by contractors and oil companies.

Methods to reduce fuel consumption are underthree sections:

1. General Conservation Practices

2. Minimizing Prime Mover Fuel Consumption

3. Modifying Drilling Practices/Machinery toReduce Prime Mover Fuel Consumption

General InformationThe amount of flywheel kilowatts (horsepower)produced by burning a liter (gallon) of diesel fueldepends on engine type, condition, and loading.If an engine is operated at more than half load,a liter (gallon) of diesel fuel can produce approx-imately 3.3–4 kW•h/l (17–20 hp-h/gal). Incontrast, the same engine lightly loaded willonly produce approximately 2.7–3.6 kW•h/L(14–18 hp-h/gal) or much less if operating atno load.

Engine fuel consumption data is stated as:

Fuel quantity consumption per hour at vari-ous loads. This is expressed in L/h or gal/h.

The engine burns fuel at no load due to the inter-nal demands of water and oil pumps, frictionlosses, other mechanical devices, etc.

This accounts for a major part of the slopein B curve, Figure 19.1. These internal lossesbecome a smaller portion of the total as the engineis loaded. Thus, the engine is more efficient.

Curve A, Figure 19.1, adds the power required tooperate the radiator fan. It is not normally includedin the engine’s fuel curve due to the wide selec-tion of radiators used in the oil field.

Note that a radiator fan that takes 5% of the enginefuel consumption to drive at full load may take16% of the engine fuel consumption at 20% load.The percentage would be much higher at no load.

Figure 19.1

General Conservation Practices

Fuel will be saved by converting small dieselengine-driven auxiliaries, such as mud mix pumps,superchargers, etc., to electric motor-driven units.As an engine-driven device, these auxiliaries arethe only load on that particular engine. Thus,when at light load, fuel consumption per flywheelkilowatt (horsepower) delivered is high.

On rigs that require winterizing, engine exhaustand jacket water heat can be recovered and reduceboiler fuel consumption.

Take measures to prevent theft of fuel.

Eliminate spillage and leakage losses.

Turn off auxiliary loads when not needed. Oper-ation of unneeded auxiliary loads may representup to 5-10% of total rig load.

Minimizing Prime MoverFuel Consumption

The following items should be considered in regardto prime movers. The secret is to get all theenergy out of each drop of fuel and avoid fuelwaste due to poor maintenance and adjustment.

Engine should be maintained to assure optimumfuel consumption. Exhaust smoke under steady-state conditions indicates incomplete combus-tion of fuel, hence, increased fuel consumption.It could be caused by such things as dirty aircleaner elements, dirty aftercooler cores, tur-bocharger malfunctioning, incorrect fuel injec-tion timing, faulty fuel injection nozzle, etc. Aqualified serviceman should be called upon toprovide a specific diagnosis.

FUEL CONSERVATION ON PETROLEUM ENGINES

LEBW1414-00 194

Turbochargers may also not be properly matchedto the engine. This can happen with engines thatare operating at a speed other than that shown onthe manufacturer’s nameplate.

In such cases an improper turbocharger matchincreases fuel consumption by 1–5%, in additionto creating other possible adverse operating con-ditions, i.e., excessive exhaust temperature, slowerengine acceleration, etc.

Reduce radiator fan power requirements. Radia-tors of the same ambient capability can havegreat differences in fan power due to fan rpm andfan diameter differences. A large diameter fan ata lower rpm can deliver the same cfm, but atgreatly reduced power demand.

Radiators are available with fans which draw 1.5to 6% of the engine rating. The effect of radiatorfan power is quantified, Figure 19.2.

Considering that drilling engines spend much oftheir time at reduced load levels, a further reduc-tion in fan power can be achieved by using a two-speed drive (electrical, mechanical, or hydraulic)to operate fan. This savings is illustrated inFigure 19.2 under the column labeled ControlledSpeed Fans. This column also reflects the factthat the engine does not operate all year round atdesign ambient conditions.

Controlled speed fan would run continuously atlow speed until hot weather/high load conditionscause engine water temperature to rise, signallingthe fan drive to run at high speed. CAUTION:Controlled speed fans may be prohibited by someemission regulations.

A single-speed fan drive that is turned on or offmay not be desirable. The radiator supplier wouldhave to be consulted to determine if the radiatorcore can tolerate the repeated temperature cyclingthat occurs. When the fan is off, the radiator out-let water is at engine water temperature and willbe cooled toward ambient as the fan turns on —

particularly at light load. This temperature reduc-tion causes the radiator core to contract. Repeatedtemperature fluctuations could result in prema-ture core failure unless the radiator can accom-modate these fluctuations.

When operating on cool or cold days, the radia-tor ambient capacity, in the low speed operation,will increase. A low temperature is always reachedwhere the engine can be cooled at full load withthe fan in low speed operation. Thus, during win-ter operations (and most summer operations) thefan may never operate in the high speed position.Figure 19.3 shows these approximate values.

Figure 19.3

For additional assurance of reliability, the two-speed drive can be arranged such that fan beltscan be reattached to the engine crankshaft pul-ley if necessary.

Radiator louvers are a desirable feature in coldclimates, but they do not reduce the fan powerdemand.

Use of a heavy distillate or crude fuel can reducefuel costs. Fuel consumption will reduce in anapproximate inverse proportion to the ratio of theheat content of this fuel to regular fuel. However,such a fuel cost reduction frequently results inincreased engine operating costs. Depending uponcontaminants or operational difficulties encoun-tered, engine life could be severely reduced.

A fuel analysis is certainly recommended. Thisshould be compared to permissible and recom-mended fuel specifications which can be providedby the engine supplier. Fuel treatment equipment

Radiator Ambient CapabilityApproximately

Engine Fan AmbientLoad Speed Capability100% 100% 125°F (52°C)100% 50% 80°F (27°C)50% 50% 125°F (52°C)

Figure 19.2

Increase in Rig Fuel Consumption Due to Radiator FanControlled Speed Fan (2:1)

Engine Load 5% Fan 2.5% Fan5% 2.5%

20–40% 12–16% 6–8% 1% 0.5%30–50% 10–14% 5–7% 1% 0.5%40–60% 8–10% 3–6% 1.5% 0.75%

60–100% 5–8% 2.5–5% 1.5–3% 0.75–1.5%

195 LEBW1414-00

may be commercially available that conditionsfuel to meet permissible or recommended fuelspecifications. It may be necessary to start andstop the engine on diesel fuel.

Used lube oil can be blended into the fuel supplywhen proper precautions are taken. However, thereduction of fuel consumption would be in therange of 0.5% — and, fuel filters would have to bechanged more frequently. It also discolors the fuelso that it cannot be returned to the supplier.

Modifying Drilling Practices/Machinery to Reduce Prime MoverFuel ConsumptionThe first drilling practice to be discussed is thenumber and size of engines used to power a rig.An SCR rig will be assumed.

The importance of engine sizing is shown byengine fuel curves, Figure 19.1.

The curve is not flat. More importantly, this is acurve for a given prime mover. Such curves arenot the same for all manufacturers and/or mod-els. In a given engine family, a V8, V12, and V16will not have identical fuel curves. Between enginemanufacturers, a V8, V12, and V16 will differ.Fuel curves give testimony to engine configura-tion differences such as: naturally aspirated, rootsblower, turbocharging, natural gas engines, dieselengines, gas turbine engines, engine size, etc.

Figure 19.4 represents such variations. All theseengines, for purposes of dramatizing the compar-ison, have the same full load fuel consumption.

Figure 19.4

An additional point is illustrated in Figure 19.5.The left side shows that two engines have thesame fuel curve — expressed as % load. The rightside illustrates that these same two engines are

different sizes — hence, their fuel rates now aredramatically different at specific load points.

This understanding of fuel curves leads to the fol-lowing conclusion.

When using fuel consumption as one of thecriterions in selecting engine sizes, types, andquantities, fuel consumption at normal oper-ating loads, not at the rated full load point, isof greatest importance. An approximation ofengine load versus time at various well depthsis also required.

Figure 19.5

Calculating or estimating fuel consumption requiresthe following:

1. Engine fuel curves — tabulated in the sameformat (and down to no load operation).

2. An actual or typical well profile that plotspower required versus days of operation.

3. A format to calculate and display the requiredinformation.

Fuel curves for Caterpillar Petroleum Engines arein the TMI or Engine Performance Book.

LEBW1414-00 196

Well profile data is required to establish the basisfor estimating engine fuel consumption. Welldepth and fuel cost are values you provide.

The well profile itself can be based on your expe-rience, on-site evaluation, documented by datarecording systems, or a combination of all of these.

It is suggested that separate drilling activitiesshould be tabulated for each diameter hole beingdrilled, hoisting time, and a grouping for nondrillingtimes such as logging, waiting on cement, etc.

Engine operating techniques reflect the fuel con-sumption consequences of the number of enginesyou operate. Granted that we recommend (andhopefully the industry concurs with) operatingengines efficiently — but what are the conse-quences of operating more engines than required?

Engine operating techniques are tabulated underthree headings:

A. Run all engines — regardless of need.

B. Run one engine more than required — thisprevents a power interruption or reduction ifa generating unit should go off the line.

C. Run minimum number of engines — realiz-ing that a temporary power reduction or out-age will occur if a generating unit should gooff the line.

DRILL RIG LOAD PROFILES

Top Hole days hp

Drilling days hp

Drilling days hp

Tripping days hp

Wait, Misc. days hp

Figure 19.6

As a general rule, tripping hp (tripping out, trip-ping in, and running casing) for the entire wellaverages 10–20% of the drawworks rated hp. Anyoperating auxiliary load has to be added.Wait, Misc., is time spent, throughout the entirewell, waiting on cement, logging, etc.The profile also assumes no generator limitationswere encountered which would have requiredmore engines running than indicated.Finally, it is a known fact well profiles vary widely.Specific well profiles should be utilized if moreaccurate results are required. It may be neces-sary to record kW and kVA values on some drillrigs to gain reliable representative data.

Engine Sizing Versus Generator Sizing

As you reflect on what has been just presented,two objections, or qualifications, may come tomind. They will be discussed separately. The firstone is expressed in the following statement:

“But my SCR rig already operates efficientlybecause it operates in power limit.”

This statement requires a word of caution — theSCR system’s power limiter or overload controlactivates for either kW or kVA overloads. A rigoperating with the power limiter light on does notmean the engines are being efficiently operated.Larger kVA generators (or other remedial action)may be needed because generators may be atkVA limit and engines at only 30–50% load!A difficulty in efficiently sizing and operating anSCR (or DC) rig is the assumption made by mostpeople that “x” amperes represent “y” power.This is not true.This fact is represented by system power factor.If power factor is 1.0, then “x” amperes represent“y” power. At power factors below 1.0, power isless than the amperes indicate.Considering that power factor on a SCR rig can,under steady-state conditions, be from 0.3 to 0.9,generator sizing is important. During hoisting,power factor varies from 0.0 to 0.95.Nontechnically, the engine supplier’s concernregarding power factor is that engine power capa-bility cannot be utilized due to generator limita-tions during low power factor operation. Thisnecessitates running additional engines. Runningof additional engines increases rig fuel consump-tion and unnecessarily increases annual hourlyusage of engines and total operating costs.

197 LEBW1414-00

There may be cases where the minimum num-ber of engines cannot be operated because of ahigh generator kVA requirement.

Before examining these variables, it is first neces-sary to review some characteristics of DC motors.

DC Motor Characteristics

The rpm of DC motors is primarily controlled bythe voltage to the motor (recognizing that motortype — series, shunt — and control system —field weakening, etc. — are related factors).

Ampere draw of the motor controls torque out-put of the motor. In other words, torque comesfrom the interaction of magnetic fields, and thestrength of these fields is proportional to amperes,not to DC voltage.

Thus, kilowatt (horsepower) load on a DC motoris the product of volts and amperes:

kW (DC Output)

= V 2 A______1000

hp (DC Output)

= V 2 A______________[ 0.746 2 1000 ]Input power would be higher in inverse proportionto motor efficiency.

This leads to the realization that a DC motor canwork hard at low rpm (draw high amperage andproduce high torque) and not load the engine(but load the generator) when operating at lowDC voltage/low rpm.

DC Motor Effects Upon Generator Selection

DC motors do not have power factor identifiedwith them. However, their DC amperes comefrom an AC generator — with an SCR systemproviding rectification. This AC current does havepower factor (pf) associated with it.

The speed/voltage characteristic of the DC motoris thus the major determinant of the system’spower factor. (System power factor is a weightedaverage of the DC motor system’s effect on thegenerator’s power factor and that of the AC aux-iliary load. The AC auxiliary load generally is onlyabout 20% of the DC load, so its effect on powerfactor is minimal).

Figure 19.7 shows a method to calculate AC gen-erator power factor due to current draw of a DCmotor powered through an SCR system.

METHOD TO CALCULATE AC GENERATOR pf DUE TO DC MOTORS

Figure 19.7

1. Determine DC kW• from meter• or formula kW

DC=

V 2 A______1000

2. Determine AC Amp of DC motor• use formula AC amp = DC amp 2 0.816

3. Determine kVA• use formula kVA =

AC Volts 2 AC amp 2 1.73________________________1000

4. Determine pf• use formula pf =

kW (from Step 1)_______________kVA (from Step 3)

LEBW1414-00 198

Figure 19.8

Figure 19.8 graphs the effect of motor rpm (orDC voltage) on the power factor of the drivingAC generators. For a constant rpm (DC voltage),power factor is the same from no load to full load.

Methods to Improve System Power Factor

The best way to improve system power factor isto ensure that DC motors are run at as high anrpm as possible.

Every DC ampere presents a 0.85 kVA load onthe generator, regardless of DC power. Operatinga DC motor at high rpm reduces ampere load,hence kVA.

On the rotary table, this means keeping the draw-works transmission in as low a gear as possible.

0

.2

.4

.6

.8

1.0

DC MOTOR SPEEDVERSUS AC GENERATOR POWER FACTOR

PowerFactor

DC Voltage (= Loaded rpm)

180 (200) 450 (600) 750 (1000)

ROTARY TABLE OPERATION

Figure 19.9

1600 hp (1194 kW) TRIPLEX MUD PUMP140 Strokes Maximum

120 Strokes Rated

Customer Needs 300 gpm @ 2500 PSI = 515 hhp(18.9 L/s @ 17237 kPa = 384 HkW)

Figure 19.10

DC Motors Geared DC Motors Gearedfor 140 spm for 100 spm

Liner Required Motor AC AC Motor AC ACSize Pump Strokes rpm pf kVA rpm pf kVA

5 (127) 97 690 .66 577 970 .92 4195 1/2 (140) 81 579 .56 690 810 .76 5026 (152) 68 486 .45 822 680 .64 5986 1/2 (165) 58 414 .4 966 580 .55 7016 3/4 (171) 54 385 .37 1035 540 .51 7537 (178) 50 357 .34 1118 500 .47 8137 1/4 (184) 47 336 .32 1189 470 .44 8647 1/2 (191) 44 314 .30 1274 440 .35 1079

114 hp (85 kW) at DC Motor _______ rpm at _______ DC Amp = _______ pf at _______ kVA960 118 .9 92860 131 .8 104750 151 .7 120640 177 .6 140530 214 .5 168425 267 .4 208325 349 .3 300210 540 .2 420150 756 .14 640

199 LEBW1414-00

To illustrate the effect of rpm, let us assumea rotary table operating under the followingconditions:

rpm = 30Torque = 20,000 lb-ft (27 138 N•m)

Power = 114 hp (85 kW)

Regardless of the rpm of the driving DC motor,engine load will stay at 114 hp (neglecting losses).But, motor rpm will change the kVA (pf) and,hence, the size of generator required. This is illus-trated in Figure 19.9.

In the extreme case of 150 rpm, it does not takea large engine to produce 114 hp (85 kW), but itdoes take a large generator to produce 640 kVA.

This phenomena of increasing AC generator kVAas the DC motor slows down may seem to reekof magic, but it is just another way of saying thatDC motor amperes are increasing as the DCmotor is required to provide the same power atlower rpms (lower DC voltage).

If DC motors are operated at half DC voltage orless, an alternative method of raising AC gener-ator power factor is to operate both drawworksmotors in series (assuming this option is avail-able from the SCR system supplier). This dou-bles the voltage out of the SCR system andproportionally raises the power factor. Systemspeed, however, is limited to half motor speed.

The same considerations apply to mud pumps.Operating speed should be as high as possible.If pumps must be operated at less than half speed(rather than putting in smaller liners) the SCRsystem supplier may be able to supply equip-ment to allow the motors to operate in series.

When mud pumps are purposely oversized toreduce cost of fluid end maintenance, the mudpump will run much lower than rated strokes. Inthat case specify a motor drive system ratio suchthat motors run at or near their rated rpm. Bothmud pump drive types are shown in Figure 19.10.

In summary, Figure 19.11 shows that requiredengine power can be determined by knowing onlyload demand (based on Figures 19.9 and 19.10).However, generator sizing also requires knowingequipment speed. The kVA values in Figure 19.12are for constant power levels but with variousequipment rpms.

Figure 19.11

Accordingly, ironclad rules for sizing generatorscannot be given. Estimates of generator sizingare shown, Figure 19.16.

Figure 19.12

This discussion illustrates that operating a rig inpower limit does not ensure efficient engine uti-lization. The goal is to operate the minimum num-ber of engines without encountering generatorlimitations.

Drawworks Capability

Let us now turn to the second objection or qualifi-cation. It is expressed by the following statement:

“My rig cannot operate on one engine dur-ing deep drilling as one engine underpowersthe drawworks.”

Many times rig operating personnel are reluctantto operate a minimum number of engines underdeep hole conditions. They express the concernthat, should they need to operate the drawworksin a hurry, one engine would not be able to “comeoff bottom,” and time would be lost while start-ing additional engines.

With proper equipment selection, this objectioncan be, at least partially, overcome. The key tounderstanding this possibility is to draw a dis-tinction between drawworks power and draw-works torque. Static hook load capacity isdetermined by generator kVA, not engine power.

Generator SizingEngine Size Generator Size

600 hp (450 bkW) 750 –1000 kVA900 hp (670 bkW) 1100–1300 kVA

1200 hp (900 bkW) 1500–1800 kVA1500 hp (1120 bkW) 1600–2000 kVA2000 hp (1490 bkW) 2000–2500 kVA

Load While DrillingkVA

hp/kW Minimum Average MaximumRt 114/85 92 209 640MP1 515/384 577 966 1274

629 hp 669 1174 1914(469 kW)

+ Aux. loadRt = Rotary Table

MP1 = #1 Mud Pumps

LEBW1414-00 200

STARTING TORQUE COMPARISON

Torque When Engine Load Drive Type Coming Off Slips When Coming Off Slips

Low High *

Direct Drive

Rated Rated

Torque Converter

Rated NIL **

Steam

Rated NIL **

DC/SCR

**Engine load is at the rated value for the engine at low idle — but the load value is low compared to rated rpm.**Engine load would be zero except for line losses, etc.

Figure 19.13

201 LEBW1414-00

This was discussed earlier under DC motor char-acteristics where it was pointed out that motortorque comes from the strength of motor mag-netic fields.To dramatize the stall torque characteristics, it isuseful to compare torque characteristics of sev-eral drives when coming off the slips — mechan-ical, torque converter, steam, and DC (SCR). SeeFigure 19.13.The startling thing shown in Figure 19.13 is thatdeveloping rated torque on a DC motor at themoment when coming off the slips does not loadthe engine. The engine is loaded in proportion tothe speed to which the motor is accelerating. Thus,the electric drive is comparable to a steam rig.Ideally an electric rig will initially accelerate thetraveling block, when coming off the slips, at aconstant rate regardless of power capability of theengine. This constant rate is determined by gen-erator kVA capacity. Motors will accelerate at thisconstant rate to the rpm at which developed powerequals engine capability. The SCR system kW limitwill then begin to reduce motor ampere draw.The motor will now accelerate at a slower rate ormaintain a constant rpm, depending on load.

These factors are illustrated by using a hypo-thetical hoisting scheme. This drawworks has thefollowing characteristics:

1492 kW (2000 hp) CapacityTwo 746 kW (1000 hp) Motors

Each MotorAt Rated At Stall

rpm ConditionsDC amp 995 1200AC amp 812 979kVA 845 1020kW (hp) 746 (1000) 0Figure 19.14 plots drawworks current, power,and hoisting time for a heavy load. Total time topull a stand of pipe is 45 seconds. (This is notbased on calculation but is sufficient to illustratethe desired phenomena.)In Part A of Figure 19.14, note that drawworksDC amperes are indicated as doing three things:1. Hold weight of pipe against gravity under

static or constant rpm conditions.2. Overcome hole friction.3. Accelerate pipe.(Note that on a direct drive or torque converterrig, it would also be necessary to accelerate theengines.)

0 10 20 30 40 50 60 70 80 90

400

800

Time

Constant Motor rp mMotorAcc elerat ion

0

2000

10002

1

3

1000

1400

0

1492 kW(2000 hp)

3 2

1

DC

Mot

or T

ota

lR

evo

luti

ons

Dra

ww

orks

Po

wer

Dra

ww

orks

Am

per

es

A

B

C

Figure 19.14

LEBW1414-00 202

In this example 1000 amps are required to holdthe weight of the pipe. The remaining 1400 ampsare initially available to accelerate pipe.

In Part B, drawworks power is indicated as beingproportioned among the same three functions.Note that drawworks power starts at zero andreaches rated power after 15 seconds. Once thedrawworks motor reaches rated rpm, the kilo-watts (horsepower) drop (and motor amps) tothat required for a constant speed condition.

If we accept 45 seconds as a reasonable estimateof heavy load hoisting time, we can count the DCmotor revolutions as shown in Part C. For thistransmission gear and lines strung, it takes 632turns of the motor to pull pipe the required 90 ft.(27.4 m). Note that during acceleration, pipe isbeing lifted, although at a slower rate.

To perform according to Figure 19.14, the draw-works has to be fully powered both with horse-power (kilowatts) and kVA (amps), which wouldbe two 3512s with 1250 kVA generators.

Figure 19.15 shows the drawworks under a lighterload condition but in the same drawworks gear.

Note that acceleration time has been reducedfrom 15 seconds to 7 seconds due to the combi-nation of having 1800 amps available for accel-eration as compared to the 1400 amps in the

previous example, and due to the lighter load toaccelerate. Hoisting time has been reduced only3 seconds, from 45 seconds to 42 seconds. Part Cindicates this by counting motor revolutions.

Figure 19.16 shows an underpowered drawworkswith the same heavy load as in Figure 19.14. Thedrawworks is now powered by one 3512 and a1250 kVA generator.

1250 kVA translates into 1470 DC amps. Com-paring Figure 19.14, Part A, to Figure 19.16,Part A, we see that this undertorqued drawworkshas only 470 amps available for acceleration whilethe fully powered drawworks has 1400 ampsavailable for acceleration. Hence, this under-torqued drawworks will accelerate much slowerthan before.

After an estimated 25 seconds, the horsepowerwill build to the rating of the engine. Accelerationwill now continue at a slower rate as the SCR sys-tem power limiter or overload control phasesback the SCR system. This reduces generatoramps sufficiently to hold generator and engineat full load. Note the engine is not loaded forapproximately 25 seconds.

Figure 19.15

0 10 20 30 40 50 60 70 80 90

400

800

Time

0

2000

10002

1

1800

0

1492 kW(2000 hp)

3 2

1

DC

Mot

or T

otal

Rev

olut

ions

Dra

ww

orks

Po

wer

Dra

ww

orks

Am

per

es

600

3A

B

C

203 LEBW1414-00

Thus, total trip time could be about 60 seconds.This time is broken down as follows:

O – X seconds Acceleration to enginepower limit

X – Y Acceleration at slower rateY – Z Constant rpm

Figure 19.17 overlays Figures 19.14, 19.15 and18.16. Part A shows the important variable is thepercentage of available DC amperes availablefor acceleration. Oversize generators provideincreased acceleration torque. Thus, the fasterthe drawworks accelerates, the sooner the enginecan be loaded. Oversize generators come closeto providing identical drawworks performance asthat obtained with additional engines operating.

For these figures to be totally representative, avail-able engine power and generator kVA should bereduced by the on-line auxiliary loads left running.

In summary, oversized generators not only pro-vided for operation of mud pumps at reducedpower factors, but they also reduce the need tofully horsepower the drawworks, as long as thedrawworks is close to being fully torqued.

Concern Over Power Outages

An additional concern expressed by some drillingpersonnel is the domino effect. That is, if the load

is equal to one and one-half engines, they preferto run three engines. It is felt that if only twoengines were operated, loss of either of two gen-erator sets would overload and stall out theremaining generator set.

This does not happen with modern SCR systemsdue to the power limiter or overload control builtinto the SCR system. This controller will phase-back one or more of the SCR-controlled loads suf-ficiently to prevent engine (or generator) overload.

Miscellaneous Considerations

With optimum usage, engines accumulate fewerhours per year but at a somewhat heavier load.

This heavier load may result in a somewhat lowertime between overhauls as expressed in engineservice meter hours. However, time betweenoverhauls as expressed in calendar years will begreater.

Additionally, there will be conditions where enginesare presently so lightly loaded that the increase inload may still leave the engine moderately loadedand service life will be only slightly affected.

A final benefit of increasing engine load is thatthe resulting warmer jacket water temperaturesgreatly aid in combating harmful effects of somefuel contaminants.

Figure 19.16

0 10 20 30 40 50 60 70 80 90

400

800

Time

Slow er Acc el.Motor Acc el. to Power Limi t

0

2000

10002

1

3

0

1492 kW(2000 hp)

2

1

DC

Mo

tor

Tota

lR

evol

uti

ons

Dra

ww

orks

Pow

erD

raw

wor

ksA

mp

eres

Cons tant Motor rpm

3

A

B

C

LEBW1414-00 204

During deep drilling, where the investment in thewell is accumulating to a considerable amountand uncertainty regarding the exact nature ofdown hole conditions is also increasing, it is ageneral practice to operate with 80% or lessengine load.

Summary

The main means available to improve fuel con-servation are:

• Use electric motor-driven auxiliaries.

• Use engine heat on winterized rigs.

• Prevent theft of fuel.

• Eliminate spillage and leakage losses.

• Turn off unneeded auxiliaries.

• Keep engines properly maintained.

• Use proper turbocharger matches.

• Reduce radiator fan power requirements.

• Operate the minimum number of engines.

• Size system for operating kVA.

• Operate DC motors in series.

• Increase motor rpm.

• Utilize oversize generators for improved hoist-ing and mud pump performance.

0 10 20 30 40 50 60 70 80 90

400

800

Time

0

2000

1000

0

1492 kW(2000 hp)

DC

Mot

or T

otal

Rev

olut

ions

Dra

ww

orks

Po

wer

Dra

ww

orks

Am

per

es

O-X Max. Motor Accel.X-Z Accel. Power Limi tedY-Z Constant Motor r pm

ZZZZ

YYYY

XX

X

2 3512 w/1250 kVA1 3512 w/1250 kVA1 3512 w/1500 kVA1 3512 w/1800 kVA

1000

A

B

C

Figure 19.17

205 LEBW1414-00

RIG NO. LOCATION DATE

ENGINE NO. 1 2 3 4 5 6 7 8 9 10

ENGINE IDENTIFICATION

Hours RunOil Added — galFuel Used — gal

rpmAir Temperature — leftAir Temperature — rightExhaust Temperature — leftExhaust Temperature — rightOil TemperatureJacket Water TemperatureAftercooler Water TemperatureOil PressureFuel Pressure

Engineman Signature:Hours RunOil Added — galFuel Used — gal

rpmAir Temperature — leftAir Temperature — rightExhaust Temperature — leftExhaust Temperature — rightOil TemperatureJacket Water TemperatureAftercooler Water TemperatureOil PressureFuel Pressure

Engineman Signature:Hours RunOil Added — galFuel Used — gal

rpmAir Temperature — leftAir Temperature — rightExhaust Temperature — leftExhaust Temperature — rightOil TemperatureJacket Water TemperatureAftercooler Water TemperatureOil PressureFuel Pressure

Engineman Signature:Remarks: Work done, parts used, cause of failure, periodic inspection, etc., identify each engine worked on.

Figure 20.1

DAILY ENGINE REPORT

LEBW1414-00 206

Figure 21.1

ENGINE SUPPORT SYSTEMS LAYOUTS

207 LEBW1414-00

A. Ducting widens as it descends to engine serv-ice walkway.

B. Exhaust is only overhead engine connection— all others under engine.

C. Raised platform completely around engines.Solid plate, with > 1 in. (25 mm) clearancearound base.

D. Engines raised 1 ft. (0.3 m) to allow passageunderneath to be used for routing piping —fuel, air, water.

1. Pedestals and spring isolators at 3 pointlocations.

2. Walkway

— Diesel Fuel Day Tank mounted on outsidewall of module.

— Engine bases supported at 3 point mountlocation.

Figure 21.2

LEBW1414-00 208

SHUTOFF AND ALARM SYSTEMS1401. Is air inlet shutoff used? . . . . . . . . . . . . . . . . . . . . . . . . . . . .1402. Is alarm panel used? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1403. Are alarms used? LOP . . . . HWT . . . . OSS . . . .

1404. Can engine disengage from compound when failure occurs,Figure 16.2? . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

OILFIELD INSTRUMENTS1301. Are premium panels used? . . . . . . . . . . . . . . . . . . . . . . . . . . 1302. How is engine load monitored? . . . . . . . . . . . . . . . . . . . . . . .

CRANKCASE BREATHER1001. Required with blower fan . . . . . . . . . . . . . . . . . . . . . . . . . . . .1002. Diameter of pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1003. No low spot in line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004. Powered disposal system . . . . . . . . . . . . . . . . . . . . . . . . . . .

AIR INTAKE SYSTEM902. Can mud enter air cleaner? . . . . . . . . . . . . . . . . . . . . . . . . . .903. Are remote mounted air cleaners used? . . . . . . . . . . . . . . . .904. Are elbows proper size, Figure 11.13? . . . . . . . . . . . . . . . . .

905. Is ducting to air cleaner airtight? . . . . . . . . . . . . . . . . . . . . . .906. Are durable flexible connections used? . . . . . . . . . . . . . . . . .

VENTILATION901. Radiator air ducted for space heating . . . . . . . . . . . . . . . . . .

EXHAUST801. Expansion joint used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802. Muffler used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .803. No exhaust recirculation to radiator/air cleaner . . . . . . . . . . .

804. Exhaust system supported separate from engine . . . . . . . . .805. Outlet protected from rain entry . . . . . . . . . . . . . . . . . . . . . . .

FUEL701. Type of fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .702. Fuel line size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .703. Fuel centrifuge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .704. Shutoff/check valves used each engine . . . . . . . . . . . . . . . . .

705. Return line goes back to fuel tank . . . . . . . . . . . . . . . . . . . . .706. Water trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .707. Fuel cooler required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LUBRICATION601. Drain plug accessible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .602. Type oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

603. S•O•S to be used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COOLING501. Radiator manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .502. Type: Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vertical discharge . . . . . . . . . . . . . . . . . . . . . . . .

503. Temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .504. Additional heat load . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .505. Antifreeze required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .506. Expansion tank supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . .

507. Rad. fan hp . . . . . . . . . . . . . . net engine hp . . . . . . . . . . . .508. Water lines slope up to radiator . . . . . . . . . . . . . . . . . . . . . . .509. Piping as large as engine connections . . . . . . . . . . . . . . . . .510. No air recirculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .511. Shutterstats used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .512. Radiators offset from engines . . . . . . . . . . . . . . . . . . . . . . . .513. Rad. adequately supported by engines . . . . . . . . . . . . . . . . .514. Dual core radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MAIN ENGINE AUXILIARY DRIVES401. Auxiliary equip driven . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 402. PTO location on engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GOVERNOR301. Hydra-mechanical with air throttle . . . . . . . . . . . . . . . . . . . . .302. UG8L with air throttle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

303. 3161 with air throttle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .304. Cat electronic . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

MOUNTING208. Are substructure pin joints tight? . . . . . . . . . . . . . . . . . . . . . .209. Can engine twist or bend? . . . . . . . . . . . . . . . . . . . . . . . . . .

210. Does engine overhang substructure? . . . . . . . . . . . . . . . . . .211. Is substructure laterally braced? . . . . . . . . . . . . . . . . . . . . . .

DRIVE SYSTEM DATA201. Torque converter model . . . . . . . . . . . . . . . . . . . . . . . . . . . . .202. Fluid coupling model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .203. Air clutch model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .204. Transmission model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

205. Engine rpm on mud pumps . . . . . . . . . . . . . . . . . . . . . . . . . .206. Engine rpm on drawworks . . . . . . . . . . . . . . . . . . . . . . . . . . .207. Clutch air pressure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL INFORMATIONA. Rig number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B. Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C. Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D. Rig-up performed by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E. Rig-up location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F. First location at . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G. Special conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H. Selling dealer or OEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .I. Engine model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rating . . . . . . . . . . . . . . . . . . . hp . . . . . . . . . . . . . . . . . rpmS/N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

J. Drive Type.All engines in one compound . . . . . . . . . . . . . . . . . . . . . . . .Independent mud pump drive . . . . . . . . . . . . . . . . . . . . . . . .Independent rotary drive . . . . . . . . . . . . . . . . . . . . . . . . . . . .Chassis mounted drawworks . . . . . . . . . . . . . . . . . . . . . . . . .Make . . . . . . . . . . . . . . . . . . . . . .Model . . . . . . . . . . . . . . . .

K. Reviewed by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .At . . . . . . . . . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . . . . . .

L. Reviewed with . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. Auxiliary power . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CATERPILLAR PETROLEUM ENGINE SYSTEM ANALYSIS — DESIGN REVIEWReference: Cat Petroleum Engine Application and Installation Guide

LAND MECHANICAL RIG

209 LEBW1414-00

GOVERNORS Check type of governor and answer appropriate questions.

FUEL701. Type of fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .702. Fuel tank’s elevation above engine . . . . . . . . . . . . . . . . . . . .703. Day tank used to relieve

pressure head . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .704. Fuel line size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .705. Fuel centrifuge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

706. Water trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .707. Return line goes back to tank . . . . . . . . . . . . . . . . . . . . . . . .708. Shutoff/check valves used on

each engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .709. Crankcase oil mixed with fuel . . . . . . . . . . . . . . . . . . . . . . . .710. Fuel cooler required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LUBRICATION601. Drain manifold used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .602. Fill manifold used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .603. Type of oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

604. S•O•S to be used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .605. Duplex filters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COOLING HEAT EXCHANGER COOLING501. Cooling Circuit Type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

JWAC . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .502. Full-load heat rejection . . . . . . . . . . . . . . . . . . . . . . . . . . . . .503. Sea water temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . .504. Sea water flow per engine . . . . . . . . . . . . . . . . . . . . . . . . . . .505. Sea water pump capacity . . . . . . . . . . . . . . . . . . . . . . . . . . .506. Cat heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .507. Cat H.E. piping . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .508. Pressure at engine inlet . . . . . . . . . . . . . . . . . . . . . . . . . . . . .509. Pressure at engine outlet . . . . . . . . . . . . . . . . . . . . . . . . . . .510. Pipe size to engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .511. Sea water strainers used . . . . . . . . . . . . . . . . . . . . . . . . . . . .512. Pressure regulating valve . . . . . . . . . . . . . . . . . . . . . . . . . . .513. Pressure gauges at engine . . . . . . . . . . . . . . . . . . . . . . . . . .514. Watermaker used . . . . . . . . . . . . . . . . . . .(answer 515-524)515. Manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .516. Number of circuits . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .517. Are engines interconnected? . . . . . . . . . . . . . . . . . . . . . . . . .518. Circuit type: Figure 7.15 . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 7.16 . . . . . . . . . . . . . . . . . . . . . . . . . .Figure 7.17 . . . . . . . . . . . . . . . . . . . . . . . . . .

519. Auxiliary JW pump . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .520. Auxiliary expansion tank . . . . . . . . . . . . . . . . . . . . . . . . . . . .521. Used per Figure 7.25 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .522. Piping free of air traps . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .523. Piping below expansion tank . . . . . . . . . . . . . . . . . . . . . . . . .524. Who is modifying engine water lines? . . . . . . . . . . . . . . . . . .Remote Radiator or Keel Cooler525. Cooing circuit type . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Remote radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Keel cooler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

526. Ambient temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .527. System external resistance . . . . . . . . . . . . . . . . . . . . . . . . . .528. Allowable external resistance . . . . . . . . . . . . . . . . . . . . . . . .529. Pressure at JW pump inlet . . . . . . . . . . . . . . . . . . . . . . . . . .530. Are engines interconnected? . . . . . . . . . . . . . . . . . . . . . . . . .531. Is piping free of air traps? . . . . . . . . . . . . . . . . . . . . . . . . . . .532. Expansion provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .533. De-aeration provisions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .534. Dual core radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

301. Cat electronic . . . . . . . . . . . . . . . . . .302. Ross Hill . . . . . . . . . . . . . . . . . . . . . .303. 2301A . . . . . . . . . . . . . . . . . . . . . . . .304. Low idle speed . . . . . . . . . . . . . .rpm

0–200 Ma control . . . . . . . . . . . . . . . . . . . . .Powered by control battery . . . . . . . . . . . . .Low DC voltage alarm . . . . . . . . . . . . . . . . .Wiring per Figure 6.10 . . . . . . . . . . . . . . . . .Installation in switchgear per Cat recommendations . . . . . . . . . . . . . . . . .

Are units paralleled for AC? . . . . . . . . . . . . .HOC control . . . . . . . . . . . . . . . . . . . . . . . .Two battery chargers . . . . . . . . . . . . . . . . . .Minimum 16 gauge stranded wire . . . . . . . .

BASE AND SUPPORT101. Base manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102. 3-point mounting used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103. Spring isolators used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

104. Adequate substructure beams under all 3 points . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL INFORMATIONA. Rig name . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B. Type rig . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C. Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D. Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E. Shipyard . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F. Location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G. Selling dealer or OEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H. First location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J. Special conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .K. Engine model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rating . . . . . . . . . . . . . . . . . . . . . hp . . . . . . . . . . . . . . . . . rpmS/N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

L. DC or SCR system manufacturer . . . . . . . . . . . . . . . . . . . . . . . .M. Generator manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Type . . . . . . . . . .AC . . . . . . . . . . . . .DC . . . . . . . . . . . . . .Quantity . . . . . . .AC . . . . . . . . . . . . .DC . . . . . . . . . . . . . .Rating . . . . . . . . .kW . . . . . . . . . . . . .Hz . . . . . . . . . . . . . .

N. Installation drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .O. Connection drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .P. Reviewed by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

At . . . . . . . . . . . . . . . . . . . . . . . . . . .Date . . . . . . . . . . . . . . . . .

CATERPILLAR PETROLEUM ENGINE SYSTEM ANALYSIS — DESIGN REVIEWReference: Cat Petroleum Engine Application and Installation Guide

OFFSHORE ELECTRIC RIG

LEBW1414-00 210

EMERGENCY GENERATOR CONSIDERATIONS2001. Engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2002. Generator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2003. Governor . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2004. Cooling: Radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Heat exchanger . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2005. Jacket water heater . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2006. Fuel day tank . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2007. Radiator ducts oversized . . . . . . . . . . . . . . . . . . . . . . . . . . . .

(in and out) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2008. External obstructions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2009. Will exhaust gas recirculate? . . . . . . . . . . . . . . . . . . . . . . . . .

2010. Air inlet extension used if engine can be started with watertight doors closed . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

2011. Spring isolators used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2012. Emergency generator support equipment on

emergency circuit . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2013. Starting: Electric . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Air . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2014. Cranking panel used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .2015. Auto transfer switch used . . . . . . . . . . . . . . . . . . . . . . . . . . .

ELECTROLYTIC AND GALVANIC ACTIVITY PROTECTION1601. Batteries grounded per Fig. 17.2 . . . . . . . . . . . . . . . . . . . . . .

SHUTOFF AND ALARM SYSTEMS1401. Air inlet shutoff used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1402. Alarm panel used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1403. Alarms used: HWT . . . . . . . . , LOP . . . . . . . . , LWL . . . . . . ,

OSS . . . . . . . . . . . . , HOT . . . . . . . . . . . . , HIAT . . . . . . . . . . . .

1404. Additional alarms:Low battery . . . . . . . . . . . , Low air pressure . . . . . . . . . . . , Low S.W. pressure. . . . . . . . . . . . . . , RPR. . . . . . . . . . . . . .

AC POWER SYSTEMS1201. RPR Trip in 2 sec . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1202. Overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1203. Generators oversized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1204. Generator controls set for enginecapacity or generator capacity . . . . . . . . . . . . . . . . . . . . . . . .

DC POWER SYSTEMS1101. Engine alarm switches connected to DC panel . . . . . . . . . . . 1102. Does driller’s console idle

engine when unloaded? . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CRANKCASE BREATHER1001. Separate line/engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1002. Line size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1003. Line sloped . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1004. Drip collector . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

VENTILATION901. Type ventilation Figure 10.1 . . . . . . . . . . . . . . . . . . . . . . . . . .

Figure 10.2 . . . . . . . . . . . . . . . Figure 10.4 . . . . . . . . . . . . .902. Ambient temperature . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

903. Temperature rise . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .904. Air required/engine (formula) . . . . . . . . . . . . . . . . . . . . . . . . .905. Air supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

EXHAUST801. Individual exhaust runs . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802. Backpressure (Figure 10.10) . . . . . . . . . . . . . . . . . . . . . . . . .803. Insulated . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .804. Thermal exp. allowed:

Vertical . . . . . . . . . . . . . . . . Horizontal . . . . . . . . . . . . . .

805. Rain-spray protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .806. No exhaust recirculation to air inlet . . . . . . . . . . . . . . . . . . . .807. Will muffler water spray

enter engine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

211 LEBW1414-00

GOVERNORS Check type of governor and answer appropriate questions.

SHUTOFF AND ALARM SYSTEMS1401. Air inlet shutoff used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1402. Alarm panel used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1403. Alarms used: LOP . . . . , HWT . . . . , OSS . . . .

1404. Additional alarms:Low battery . . . . . . . . . . . . , Low air pressure . . . . . . . . . . ,RPR . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AC POWER SYSTEM1201. RPR trip in two seconds . . . . . . . . . . . . . . . . . . . . . . . . . . . .1202. Overload protection . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1203. Generators oversized . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

1204. Generator controls set for NET engine hp or generator capacity . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

DC POWER SYSTEM1101. Engine alarm switches connected to DC Panel . . . . . . . . . . . 1102. Does driller’s console idle when unloaded? . . . . . . . . . . . . . .

CRANKCASE BREATHER1001. Required with blower fan or

front-mounted generator . . . . . . . . . . . . . . . . . . . . . . . . . . . .1002. No low spot in line . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .1003. Diameter of pipe . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

AIR INTAKE SYSTEM902. Remote-mounted air cleaners used . . . . . . . . . . . . . . . . . . .903. Are elbows proper size, Figure 11.13? . . . . . . . . . . . . . . . . .

904. Is ducting to air cleaner airtight? . . . . . . . . . . . . . . . . . . . . . .905. Are durable flexible connections used? . . . . . . . . . . . . . . . . .

VENTILATION901. Radiator air ducted for space heating . . . . . . . . . . . . . . . . . . .

EXHAUST801. Expansion joint used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .802. No exhaust recirculation to radiator/air cleaner . . . . . . . . . . .

803. Is exhaust system supported separate from engine? . . . . . .804. Outlet protected from rain entry . . . . . . . . . . . . . . . . . . . . . . .

FUEL701. Type of fuel . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .702. Fuel line size . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .703. Fuel centrifuge . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .704. Shutoff/check valves used each engine . . . . . . . . . . . . . . . . .

705. Return line goes back to fuel tank . . . . . . . . . . . . . . . . . . . . .706. Water trap . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .707. Fuel cooler required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

LUBRICATION601. Drain plug accessible . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .602. Type oil . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

603. S•O•S to be used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

COOLING501. Radiator Manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .502. Types: Blower . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Suction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .Vertical discharge . . . . . . . . . . . . . . . . . . . . . . . .

503. Temperature . . . . . . . . . . . . . . . Altitude . . . . . . . . . . . . . . .504. Expansion tank supplied . . . . . . . . . . . . . . . . . . . . . . . . . . . .

505. Antifreeze required . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .506. Radiator fan hp . . . . . . . . . . . NET engine hp . . . . . . . . . . .507. Water lines slope up to radiator . . . . . . . . . . . . . . . . . . . . . . .508. Piping as large as engine connections . . . . . . . . . . . . . . . . .509. No air recirculation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .510. Dual core radiator . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

301. Cat electronic . . . . . . . . . . . . . . . . . .302. 3161 . . . . . . . . . . . . . . . . . . . . . . . . .303. Ross Hill . . . . . . . . . . . . . . . . . . . . . .304. 2301A . . . . . . . . . . . . . . . . . . . . . . . .305. Low idle speed . . . . . . . . . . . . . .rpm

0–200 Ma control . . . . . . . . . . . . . . . . . . . . .Air supply pressure . . . . . . . . . . . . . . . . . . .Powered by control battery . . . . . . . . . . . . .Powered by control battery . . . . . . . . . . . . .Low DC voltage alarm . . . . . . . . . . . . . . . . .Wiring per Figure 6.10 . . . . . . . . . . . . . . . . .Installation in switchgear per Cat recommendations . . . . . . . . . . . . . . . . .

Are units paralleled for AC power? . . . . . . .HOC control . . . . . . . . . . . . . . . . . . . . . . . .Two battery chargers . . . . . . . . . . . . . . . . . .Minimum 16 gauge stranded wire . . . . . . . .

BASE AND SUPPORT101. Base manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .102. Coupling manufacturer . . . . . . . . . . . . . . . . . . . . . . . . . . . . .103. Roof over engines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .104. Service platform . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .105. 3-point mounting used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

106. Base will be supported on: Planks . . . . . . . . . . . . . . . . . . . .Concrete . . . . . . . . . . . . . . . . . .Hard pan . . . . . . . . . . . . . . . . . .

107. Subbase used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .108. Substructure used . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

GENERAL INFORMATIONA. Rig number . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .B. Owner . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .C. Address . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .D. Rig-up performed by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .E. Rig-up location . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .F. First location at . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .G. Special conditions . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .H. Engine model . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Rating . . . . . . . . . . . . . . . . . . . hp . . . . . . . . . . . . . . . . . rpmS/N . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

I. DC or SCR system mfr . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .J. Generator mfr . . . . . . . . .DC . . . . . . . . . . . . .AC . . . . . . . . . . .

Type . . . . . . . . . . . . .AC . . . . . . . . . . . . .DC . . . . . . . . . .Quantity . . . . . . . . . . .AC . . . . . . . . . . . . .DC . . . . . . . . . .Rating . . . . . . . kW . . . . . . , Hz . . . . . . . , pf . . . . . . . . . .

K. Installation Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .L. Connection Drawing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .M. Reviewed by . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

At . . . . . . . . . . . . . . . . . . . . . . . . . . . Date . . . . . . . . . . . . . . . .N. Reviewed with . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .O. Selling dealer or OEM . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

CATERPILLAR PETROLEUM ENGINE SYSTEM ANALYSIS — DESIGN REVIEWReference: Cat Petroleum Engine Application and Installation Guide

LAND ELECTRIC RIG

Materials and specifications aresubject to change without notice.

LEBW1414-00Supersedes LEBW5119 PRINTED IN U.S.A.CATERPILLAR and CAT are trademarks of Caterpillar Inc.

Available electronically in the Technical Information section ofhttps://oilandgas.cat.com