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Dated: 6 Aug. 2001

Annexure “B”- Spec. GC-5000- Turbine and Generator

1. Vibration and dynamic

1.1 Design

1.1.1 General

A. Turbine shall be designed to minimize and withstand vibration according to

I.E.C. specification, and according to the relevant S & L specification (MSS

10.1), which ever is more severe.

B. Balancing of the Turbine shall be according to ISO 1940, latest edition.

Balance Quality Grade shall be G2.5 or better.

C. Vibrations measurements, measurement technique, location, measurement

equipment, criteria and limitations shall also meet the requirements of ISO:

7919-1, 7919-2, 10816-1 and ISO 10816-2 (=hereby ISO Standard) for new

equipment. Unless otherwise specified, the recommendations for vibrations

criteria in ISO Standard which are more severe from the requirements of

para. 1.1.1 (A) above shall be mandatory under this specification.

D. The Generator shall be design to minimize and withstand vibrations

according to NEMA MG-1 requirements for large machines.

E. Unless otherwise specified, alarm settings and limitations shall be according

to A.M. ISO standards Recommendations.

F. Critical speeds definitions under this specification:

Critical Speed: Rotative speed corresponding to a lateral natural frequency

of a rotor in which the amplification factor is more then 2.5.

H. The vibrations of the Turbine and Generator during rated speed operation

and run up/coast down of the units will be such that, continuous safe and

reliable operation of the unit shall be ensured. The vibration level in all speed

range shall not exceed the level specified by ISO Standard.

1.1.2 Any Critical responds of each rotor will fail to meet the separation margin

requirements according to API 612 standard Para. 2.8.2.5 and 2.8.4 But in

any case the separation margin shall be not less then 15% above and 10%

below rated speed limits, which is more sever.

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1.1.3 Unless otherwise specified, The Contractor shall provide complete Torsional

and Lateral Vibration Analysis. The analysis shall be done according to API

612 standard Para. 2.8 requirements and shall meet this API standard

limitations.

A. The complete Structural support system shall be taking into account for the

analysis.

B. The damped unbalance response analysis shall indicate that the machine in the

unbalanced condition will meet the acceptance criteria for separation margin as

described in paragraph 2.8.2.5 of the standard API 612.

C. The calculated unbalanced peak to peak rotor amplitudes at any speed from zero to

trip shall not exceed 75% of the minimum design diametrical running clearances

throughout the machine (with the exception of floating ring seal locations).

D. The torsional resonances of the complete train shall be at least 10% above or 10%

below the operating speed of the machine, 3000 rpm (50 Hz).

1.1.4 The Turbine and Generator assembly shall be supplied with a radial and axial shaft

vibration detecting system, including probes, indicators, 4-20mA transmitters and

alarm/trip switch power supplies, adequate NEMA 4X Type enclosures and

appurtenances.

1.1.5 Equipment vibration requirements and criteria

A. The Turbine rotor relative vibrations shall not exceed the level of 80 m, peak-to-

peak, according to the requirement for new equipment of ISO 7919-2 Standard. This

requirement is related to relative shaft vibrations of turbine generator sets, at

running speed of the unit 3000 rpm (50 Hz) (evaluation Zone “A”).

B. The bearing Housing/pedestal vibrations shall not exceed the level of 34 m, peak-

to-peak, noting that this requirement is for new equipment according to evaluation

Zone “A” in ISO 10816-2 Standard . This requirement related to turbine generator

sets, on low frequency foundations, at running speed of the unit 3000 rpm (50 Hz).

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1.2 Testing:

A. General

1.2.1 General QA requirements:

For QA requirements refer to Appendix “A”.

1.2.2 Vibration Testing:

B. Shop Test:

Turbine +Generator:

1.2.2.1 Vibrations and dynamics balancing shop test

Dynamics balancing of major parts of the rotating element and assembled

rotating elements will be performed according to requirements of paragraph

2.8.4 of API 612.

The shop test of the assembled machine with the balanced rotor, at specified

operation will meet specified unfiltered vibration limit values.

Electrical and mechanical run out will also be determined.

1.2.2.2 The Contractor shall be responsible for performing a shop verification of

unbalanced response analysis, according to paragraph 2.8.3 of API 612

standard.

A. The Contractor shall be responsible for measurements of the actual critical

speed responses of the unbalanced rotor on the test stand.

B. The measurements shall include speed, shaft vibration amplitudes and

phase.

The Peak to Peak Resultant amplitude value of each response peak shall not

exceed the limits specified in Para. 1.1.5.

C. During the shop test of the machine, assembled with the balanced rotor,

operating at its speed, 3000 rpm (50Hz), the vibration, measured on the shaft

adjacent and relative to each radial bearing, shall not exceed the value of 50

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m, peak-to-peak, for the turbine and 50 m, peak-to-peak, for the generator

and exciter.

1.3 Field Testing and Balancing

Turbine + Generator:

1.3.1 After full installation the Same tests as shop tests shall be carried on by the

contractor at the power station according to ISO 1940, ISO 10816, and ISO

7919 to assure that the equipment and its performance comply with the

requirements of the specifications and of the guarantees.

1.3.2 Any measured Critical responds of each rotor will fail to meet the separation

margin requirements according to API 612 standard Para. 2.8.2.5 and 2.8.4

But in any case the separation margin shall be not less then 15% above and

10% below rated speed limits, which is more sever.

1.3.3 The acceptance criteria for the machine, based on the measurements

from this test shall indicate:

(a) At no speed, the shaft deflections shall not exceed 90% of the minimum

design running clearances.

(b) During operating speed at 3000 rpm (50 Hz), the shaft deflection at the

probes, shall not exceed 55% of the minimum design running clearance or 40

m, 0-peak, for the Turbine and 40 m, 0-peak for the Generator

1.3.3 Major parts of the rotating element, such as shaft, balancing drum, and

impellers shall be dynamically balanced according to ISO 1940.

A. The rotating element shall be multiplane dynamically balanced during

assembly.

B After the final balancing has been completed, a residual unbalance check

shall be performed and recorded as described in Appendix “D” of API 612

standard.

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1.4. TESTING AND BALANCING DOCUMENTS

1.4.1 General

Documents, Reports and shop test records shall be, including but not limited

as required in this specification and as required in relevant parts of API 612

standard including the full requirements of Appendix E of that standard.

They will be submitted to the Purchaser according to agreed time table

1.4.2 Data of vibration test results shall be evaluated with the aid of vibration

performance chart based on API 612 or ISO standard criteria, whichever is

more severe.

1.4.3 The Contractor shall perform and submit to the Purchaser the results of

dynamic analysis and shop test verifications of the dynamic properties of the

unit components as specified in chapter 2.8 of API 612 Standard (latest

edition).

The following aspects shall be included:

A The analytical determination of machinery Critical Speeds for potential

exciting frequencies which are less, equal or greater than the rotational

speed of the rotor by means of a damped unbalanced rotor response

analysis according to paragraph 2.8.1 of API 612 Standard.

B. Compatibility of support system resonance and drive train critical speeds with

the critical speeds of the machinery being supplied shall be determined and

reported to the Purchaser (para. 2.8.1.6, 2.8.1.7 of API 612 Standard).

1.4.4 A lateral analysis (damped unbalance response analysis) for each machine

and for the whole train shall be performed and provided, in order to assure

acceptable amplitudes of vibration at any speed from zero to over speed trip

according to paragraph 2.8.2 of the API 612 standard. This analysis shall

include:

(a) a plot and identification of the mode shape at each resonant speed from

zero to trip, as well as the next mode occurring above the trip speed;

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(b) frequency, phase and response amplitude data at the vibration probe

locations through the range of each critical speed;

(c) modal diagrams for each response in item (b) above, including reference

to couplings, bearing centerlines, location of vibration probes and

machine seal areas;

(d) An additional plot of a test unbalance with prescribed test weight and

conditions (for the purpose of the verification test according to para. 2.8.3

of API 612)

1.4.6 Torsional analysis of each machine and of the complete coupled unit train for

possible excitation sources shall be performed (according to para. 2.8.4 in

API 612 Standard).

It refers to: calculation and acceptance criteria for torsional criticals at

operating speed, operating speed harmonics and possible non-synchronous

excitations; also stress analysis if necessary and transient torsional analysis

will be performed.

1.4.7 Shop verification of unbalanced response analysis (according to paragraph

2.8.3 of API 612 of API Standard).

1.5 Reports and certifications

- The charts of Shop and Filed vibration tests including, but not limited to the

following, shall be submitted to the Purchaser for review and approval:

- results of peak-to-peak displacement measurements of shaft vibrations,

and/or RMS vibration velocity of bearing.

- Results of detailed vibration analysis.

- Summary of the results, including brief conclusions showing that the results

are within all limitations.

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1.6. MEASUREMENT

1.6.1 Long Term Vibration measurements will be performed:

(a) On the shaft - relative or absolute displacement in radial planes adjacent

to the two (2) bearings of each of the Turbine and Generator rotors. For

each bearing measurement shall be performed with two (2) transducers

mounted in the same transverse plane perpendicular to the shaft axis

mounted 90 degree apart, on the same bearing half for each bearing.

(b) On machine surfaces or bearings.

1.6.2 The Contractor will specify monitoring system and vibration limits as following:

(a) Proposed vibration monitoring system according to the aims listed by

ISO Standard and appropriate measurement methods.

(b) Alarm and trip values for its conventional vibration measurement system

(bearing and shaft vibration).

(c) Additional relevant parameters and process variables to be incorporated

in the vibration measuring and monitoring system, according to its

standard practice.

1.6.3 Plant Noise and Building vibration

A. For Plant Noise and Building vibration requirements see IEC Spec. No.

92/252/3.30 “Environmental Noise and Vibration Requirements for Turbine

Generator Units” and ISO 2631 and ISO 2631-2.

B. Noise monitoring system

The Contractor will specify the requirements Noise measurement and

monitoring system (see Table 3 of attached Spec. No. 92/252/3.30

“Environmental Noise and Vibration Requirements for Turbine Generator

Units”).

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1.7 Monitoring equipment

The contractor shall provide a continuous bearing vibration monitoring

system as follows:

1.7.1 Bearing vibration measuring system

a) Each Turbine and Generator unit shall be provided with two (2) radially and

one (1) axially mounted seismic probes for measuring each bearing

vibrations. The transducers shall be mounted as follows:

- Two (2) Seismic transducers to measure vibrations on each of the

Turbine and Generator bearing. The transducers shall be mounted in the

radial direction, 45º to the vertical.

- one (1) seismic transducer to measure axial vibrations of the thrust

bearing housing

b) The bearing housing shall be furnished with appropriate surfaces, for the

mounting of the seismic transducers, (bosses or raised surfaces located at

the points of measurement for permanent mounting of the seismic

transducers).

The chosen locations shall be based on optimum transmissibility of the

vibration through the bearing housing and accessibility.

c) The protective monitoring system, based on bearing vibration survey shall be

supplied with two channel velocity monitors.

1.7.2 A shaft vibration measuring system

Each Turbine and Generator unit shall be provided with Two (2) pairs of X –

Y proximity probes for shaft vibration measurement on each bearing and at

least one key phasor for measuring shaft rotational speed and phase angle,

as follows:

a) X – Y dual proximity transducer system for each of the Turbine and

Generator bearings for the detection of shaft vibration relative to the

bearing housing.

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b) The proximity probes shall be radially oriented at each bearing housing

and spaced 90º apart. The probes shall be mounted 45º (5º) from each

side of the shaft vertical center plane, so that one of them will be at a

position as close as possible to the seismic transducer measuring the

bearing housing vibrations.

Viewed from the driver end of the Turbine, the probe mounted on the left

side shall be designated the Y-probe of the shaft, and the probe mounted

on the right side of the shaft shall be designated the X-probe. Each

bearing where vibration is measured shall utilize the same arrangement.

c) At least one proximity probe key phasor shall be supplied to measure

shaft rotation speed and phase angles. Axial float and differential

expansion between reference mark and probe shall be considered when

locating the reference mark and probe.

The proximity probe shall be of the same type and manufacturer as the

other proximity probes. The proximity probes shall be supplied complete

with cable, proximitors, and power supply.

1.7.3 The general design, conventional hardware, transducer and sensors

arrangement of the vibration measuring and monitoring system supplied by

the Contractor shall be according to API 670 and API 678 standards.

1.7.4 The Contractor shall furnish all required probe power supplies as part of the

monitoring system and signal conditioning devices mounted locally near the

a. m. transducers.

The signal-conditioning devices, probe and transducer housings shall meet

NEMA 4X requirements.

1.7.5 The Contractor shall provide the System Configuration Plan of the

turbogenerator vibration measuring and monitoring hardware including the

manufacturer and model numbers.

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1.7.6 The Contractor shall establish the vibration limits for alarm and the limit for

shutdown of the turbogenerator. Values shall be within accepted limits as

specified in Para. 1.1 E above.

1.7.7 Each vibration transducer shall be calibrated using the actual transducer

system to be installed on the machine. This calibration shall be verified and

documented by the agency that installs the transducer in the machine.

For proximity transducers a graph of the gap (a minimum of 10 points in both

mils and micrometers) versus the transducer’s output voltage shall be

prepared and supplied to the Purchaser.

1.7.8 The bearing and shaft measurement system, including rotational speed and

phase data shall permit easy access for external connection to vibration

analysis and/or recording instruments.

1.7.9 Each vibration monitoring channel shall have two (2) contacts, one for alarm

and one for trip, each rated at 125V DC capable of breaking 0.1 (Amp)

inductive current and an 4-10mA output for Purchaser’s use.

1.7.10 The monitoring system shall include the necessary communication link,

which shall enable the integration of all the data in the Plant Vibration

Diagnostic System provided by others.

1.7.11 The Turbine Supervisory Instrument System shall provide alarm signals from

the vibration and differential expansion channels, in case they should exceed

preset limits to the plant Process Control and Management System supplied

by others.

1.7.12 The generator monitoring system provided, shall be supplied complete with

all sensors necessary to detect, transmit, alarm and conditions generator and

auxiliaries malfunctions, and to assure safe, reliable and economic operation

of the Turbine Generator Unit.

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1.7.13 Options

A. The Contractor shall further provide an proposed option for Vibration

Monitoring System and Vibration Analysis Software based on his common

standard practice.

1.8 Long Term vibration criteria and alarms - after commissioning

1.8.1 Field vibration criteria for the turbine generator units

The field measured vibrations of the Turbine and Generator unit shall not

exceed at steady state operation the range classified as “Zone A” at least for

18 months after their commissioning according to the following:

- Bearings, according to ISO 10186-2 standard.

- Shafts, according to ISO 9719-2 standard.

1.8.2 Alarms:

According to ISO 9719-2 requirements the ALARM value should be set

higher than the baseline by an amount equal to 25% of the upper limit of

Zone B. If the baseline is low, the ALARM may be below the Zone C (see

Tables A.1and A.2 in ISO 9719-2).

If the steady-state baseline changes (for example after a machine overhaul),

the ALARM setting should be revised accordingly. Different operational

ALARM settings may then exist for different bearings on the machine,

reflecting differences in dynamic loading and bearing support stiffness.

1.8.3 Settings of TRIPS:

The Contractor shall submit to the Purchaser the TRIP values for Turbine

Generator shaft vibration.

The TRIP values recommended by ISO 7919-2 and 10816-2 Standards for

maximum shaft and bearing vibration ARE MANDATORY.

The TRIP values will generally relate to the mechanical integrity of the

machine and shall depend on any specific design feature which has been

introduced to enable the machine to withstand abnormal dynamic forces.

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Annexure “C2”- Spec. GC-5000 - Turbine and Generator

1. Does machine pass trough critical speed of any parts in coming up?

(if So , what part and what rpm?

- Turbine

- Generator

- Exciter

2. Calculated all Designed Lateral Critical Speed (R/min), that are below

rated speed

- For each Turbine Rotor

- Generator

- Exciter

3. Calculated all Designed Torsional Critical Speed (R/min), that are

below rated speed

- For each Turbine Rotor

- Generator

- Exciter

4. Maximum allowed Lateral vibration amplitude (p-p) during start up and

shut down for: bearings house and rotor (μm)

- For each Turbine Rotor

- Generator

- Exciter

5. Maximum allowed Lateral vibration amplitude (p-p) during steady state

for: bearings house and rotor (μm)

- For each Turbine Rotor

- Generator

- Exciter

6. Maximum allowed Lateral vibration amplitude (p-p) in frequencies

double then the rated speed for steady state for: bearings house and

rotor (μm)

- For each Turbine Rotor

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- Generator

- Exciter

7. Maximum allowed vibration amplitude (p-p) for the

base and foundation

- In steady state condition

- In critical speeds

8. Maximum allowed Lateral vibration amplitude (μm p-p) for rotor shaft

after it balancing at critical speed:

- For each Turbine Rotor

- Generator

- Exciter

9. Vibration Monitoring system for Rotor and Bearing:

- Type (s)

- Manufacturing (s)

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Appendix “A”- General QA requirements

A.1 The contractor shall submit to the Purchaser all the necessary information

describing the manufacturer's testing facilities, including test shop, testing

and instrumentation capabilities, and the tests, which are included in the

Contract Price.

A.2 The Purchaser shall have the right to appoint inspectors authorized to follow

the progress of the work and the manner in which it is being carried out, to

inspect materials at manufacturer or at the point of delivery, to reject

defective materials either at the source of supply or point of delivery at any

time, or to suspend work which is not being done properly or is not in

accordance with the plans and specifications.

A.3 The Purchaser's inspector shall have free access to the manufacturing

plant(s) and to all parts of the Vendor's plant engaged in work or equipment

and materials to be supplied to the Purchaser, at all reasonable working

hours while work is being performed on this specifications.

A,4 The Purchaser shall have the right after the complete erection of the

equipment to make, at its own expense, such field tests as it may deem

proper or necessary to satisfy itself that the equipment meets the

requirements of the Specifications in every respect. The contractor shall have

the right at its own expense to witness such tests to ensure that the

equipment is operated properly and to make such observations as he may

desire.

In making tests under this specification no minus (-) tolerance or margin shall

be allowed with respect to capacity, or efficiency at the rated or specified

conditions.

A.5 If the equipment fails in any respect to meet the requirements of the

Specifications or guarantees, the Contractor shall immediately, and at its own

expense, make such repairs, alterations and/or replacements as may be

necessary to assure that the equipment and its performance shall conform to

the requirements of the Specifications and guarantees. The Contractor shall

also, at its own expense, make such additional factory tests as the Purchaser

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may require to show the effect on the equipment and its performance of such

alterations and replacements.

Field tests shall be done by the Purchaser at the Power Station to assure that

the equipment and its performance shall conform to the requirements of the

specifications and guarantees.