Alignment

Why Alignment is needed?

What is Alignment ?

Types of Misalignment

Precondition before doing Alignment

Method of doing Alignment

DrivesAlignmentFor Coupling DrivesFor Belt Drives

Necessity of AlignmentMisalignment is a single major cause of most failures of rotating equipment's, it will lead to failure of coupling,bearings, seals as well as other components as a result of high vibration. Hence it is important to check the alignment periodically .

Definition Alignment is the process of :

1. Coinciding the shaft axis of Driver and Driven in the single straight line for coupling drives

2. Bringing the Driver and Driven shaft axis in parallel,Bring the face of pulleys in a straight line for Belt drives

TYPES OF MIS ALIGNMENT

TOP VIEWTYPE 1 (Angular Horizontal Right)

TOP VIEWTYPE 2 (Angular Horizontal Left)

SIDE VIEWTYPE 3 (Angular Vertical Up )

SIDE VIEWTYPE 4 (Angular Vertical Down)

TOP VIEWTYPE 5 (Radial Horizontal Right)

TOP VIEWTYPE 6 (Radial Horizontal Left)

SIDE VIEWTYPE 7 (Radial Vertical Up)

SIDE VIEWTYPE 8 (Radial Vertical Down)

Dial GaugeDial indicator or dial gauge is used for measuring the linear movement very accurately.The smallest measurement is 0.01 mm , total stroke is 10mm When the plunger of dial gauge moves inwards thepointer shows positive reading (needle rotates clock wise) ,when it moves out wardshows a negative reading ( needle rotates anti clock wise)

Precondition for Alignment1.Soft Foot(soft foot means un even fixing of motor base)To find out if soft foot exists, keep the motor bolts loose, gently lift each foot one by one and remove all the shims .Tighten the all foots normally, place the dial gauge over foot & loose the bolt one by one, check the lifting of the foot, give the required shims accordingly. Or check the same by feeler gauge repeat the same for driven equipment also

Proper alignment can achieved under proper condition only

Sheet1

2.Pipe Strain An improperly supported piping system can easily disturb the alignment. To identify the influence of existing piping strain, keep one dial gauge vertically (12 oclock position) and the other horizontally (9 oclock position) on the pump hub. Loosen the suction, discharge pipe flanges & any additional support for the over hanging pump. Watch for any noticeable change on the dial gauge. If any, reinstall the piping supports until there are no adverse effect of piping strain

3. Thermal GrowthThe manufacturers of large rotating equipment (ex. Turbine) usually specify the extent to which thermal expansion must be compensated for while carrying out alignment

Fixing of Dial Gauge Attach a clamp to the dial gauge and set it on a coupling hub firmly, and note the following points

1. There should not be any gap between the plunger and the hub.2.Prefer to load the gauge by setting the plunger pressed inwards say 2mm.3. If the pointer reads other than 0, rotate the dial to 0 before starting.4. Rotate the hub over 360 with the plunger touching the hub; You should read 0 after this full rotation.5. Make marks on coupling in the 12,3,6&9 oclock positions.6. Take a reading and check the sum of the horizontal reading is equal to the sum of the vertical reading, if not suspect that the set-up of the dial gauge is not correct.

Methods of Alignment2.Rim& Face3.Reverse Dial

1.Straight EdgeAlignment4.Laser alignment

Straight Edge MethodBy this radial alignment is doing with the help of steel rule hacksaw blade and axial alignment by feeler gauge Fixed m/cMotor to be shimmedFixed m/cMotor to be shimmed

Rim & Face MethodStep1- Fix the dial gauge as shown in figure, one dial should on flange RIM and another on flange FACE. Make the trial rotation to ensure that it is not fouling with anything else, is it read for over 360.Step2- If there is any pull by terminals of motor, remove it to avoid pulling load of the cablesStep3- Mark the flanges for 12,3,6 & 9 oclock position. 12 oclock position should be at center of the motor by top viewMotor to be shimmed

Step4:- Check the motor leg distance, flange diameter.(Allowable tolerance for normal equipment is for axial

Step5- Do the horizontal alignment(side out) so that the axial & radial readings approximately equal to zero at 3,9 oclock positions by adjusting motor side-jack screws

Step6-Take 2-3 readings and ensure that the horizontalreading is equal to vertical reading. If not equal the setting, marking is incorrect and make it propereg. readings

Step7-Apply the readings in the formula given bellow

First Leg Shim(FLS) = (L1*A/d) + R/2

Second Leg Shim(SLS)= (L2*A/d) + R/2

If result is in -ve value remove shims,If it is in +ve value add shims

Plotting graph for the Rim & Face method

Step8-Again check the dial gauge reading, if it is come under the tolerance tighten the bolt. If not, take more reading and add/remove shims accordingly mostly by 2-3 readings you will get alignment for the equipment.

If after tighten the bolt, alignment reading get more variation then there may be the problem in soft foot, hole of the motor and base is not getting match. Make it proper and do the alignment

Step9-After getting aligned, couple the motor & pump without disturbing the alignment(before couple the flanges check for the distance between couplings as required)

* If only one dial gauge is available first do the axial alignment and then radial

Reverse Dial MethodStep1- Fix the DBSE(distance between shaft ends) as specifiedStep2- Assemble the dial gauge with the help of alignment clamps as in figure. Step3- Ensure that the center line of the motor and the fixed machine(pump) are aligned, as viewed from top. This can be done by adjusting the motor side jack screws in a such a way that the dial gauges read approximately equal at 3 and 9 oclockposition as indicated in the figure below

Step4-Verify that the dial gauge plungers are still touching the hub flanges and set them to zero when D-1( Dial on pump flange ) in top position . Now rotate both hubs together through 180 deg in the same direction .

Record the total indicator reading for each gauge when D-1 at the bottom position. while doing this, check again that the readings at 3 o clock and 9 o clock positions are not disturbed.

Step 5 :- Measure the distance between the dial gauges and the plungers as shown in the drawing below. Also measure the distance between gauge plunger of driven pump to the motor feet

Apply the readings in the formula given below

d2= D2/2, d1 = D1/2

FLS= ((d1-d2)xL2/L1) - d1SLS= ((d1-d2)xL3/L1) - d1If negative result comes shims to be removedIf positive result comes shims to be added( OR )Plot these distance on the graph sheet and put the readings as d1 in C1 & d2 in C2 and draw the line

Step 6 :-The correction required to level the motor feet depends on where the plotted line cut the vertical axis on F1 and F2.

Plotting the graph for Reverse indicator method

Step 8 :- After carrying out the corrections ensure the followinga) The reading at 3 o clock and 9 o clock positions are still approximately equal

b) Confirm DBSE ( Distance Between Shaft Ends ) against the specification

c) secure base bolts

d) Take the final set of TIR readings on both the hub flanges

e) Verify if the corrected TIR is within 0.05 mm OR tolerance which given by the manufacturer

LASER ALIGNMENT1. Target2. Infrared Data Receiver3. Laser4. System Display5. Ruggedized laptop computer6. Mounting Brackets

Laser

The L-575 uses two adjustable, visible-diode ClassII laser beams with an operating range of up to 30'.Angular accuracy of the system is guaranteed to10 micro radians. Set-up time is minimal. In mostcases, you can show misalignment data and calculateshims and moves in as little as 5 minutes.

Target

The T-1275 features a true 5-axis target thatreads both horizontal and vertical center and anglemeasurements simultaneously. Target data is sentinstantly via an IR link to the CPU for real-timeprocessing, analysis and display of misalignmentdata. Largest cell size on the market accommodatesthermal growth offsets up to 1".

Infrared Data Receiver

Unlike competitive systems that rely upon unstableAM frequencies, our in-house designed A-908 wire-lessIR link is an extremely robust, FM-based unit.Data is sent up to 15 times per second via the mostreliable IR link on the market today. Successfullyproven in field use, at distances of 120', by a majoraircraft manufacturer since 1994.

Mounting Brackets

A-907 standard mounting bracket sets are designedto work with shaft diameters ranging in size from3/ 8 " to 12". Brackets can be adapted to 18" shaftdimensions with additional chain links. Laser andtargets are pre-aligned to brackets to facilitaterough-in alignment. Magnetic mounts standard.Speed nuts allow quick, easy set-up.

System Display

Belt AlignmentStep1-Take some thread and place it as shownin figure, check whether it is touching all the four corners properly or not.

Step2-If not, adjust the motor/pulley to touch the thread in all the four corners

Step3-Place the recommended belt,

Step4-Adjust the tightness of belt to therecommended belt tension

Questionnaire ?