Grundfos Alignment-White Paper

7/29/2019 Grundfos Alignment-White Paper

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GRUNDFOSWHITE PAPERALIGNMENTby Greg Towsley

W ith requirements o organizations to cutcosts and manage operation and main-tenance budgets better, minimizing equipmentdowntime has become increasingly important.An aspect o trouble-ree operation is the align-ment o rotating equipment.

Alignment should be completed on any equip-ment that has a driver and driven equipment.

It should not be standard practice to only alignhigh energy or high-speed pumps. ALL pumpsshould be considered or alignment.

To provide an overview o alignment, the discus-sion in this article applies primarily to horizontalcentriugal pumps that are operating in a generalservice and driven by a separate driver through aexible coupling on a common baseplate.

Many o the terms and techniques described canbe used or other types o pumps and rotatingequipment, but the installation and operationinstructions should be ollowed as required by

the manuacturer.This article is meant to be used as a primer only.Extensive training and practice should be complet-ed prior to aligning equipment that is in service.

GENERAL

The lack o alignment, or misalignment, is acondition where the rotating centerlines otwo or more machinery shats are not in linewith each other. This is not easy to detect whenmachinery is running. The rotating equipment isaligned ollowing a series o detailed steps o a

ew alignment techniques.It can be said that the goal o alignment is toposition the equipment so that any deviationso the shat centerlines are below specied orrequired criterion. Further, the objective is to

Figure 1. Impact of Misalignment onContinuous Operating Life

minimize equipment downtime and maximizethe operating lie o the rotating equipment.

Misalignment o rotating equipment can havemany aects on the equipment and the entiresystem. As can be seen in Figure 1, the greater themisalignment, the greater the reduction in timethe equipment can continuously run until ailure;the lower the misalignment, the greater the

length o time between ailure due to the eectso misalignment.

Some o the aects o misalignment include:

Bearing lie o the pump and the driver canbe reduced due to misalignment causing hightemperature or oil leakage.

Although exible coupling manuacturersadvertise that their design can compensate ormisalignment, mechanical seals can ail due toalignment that is not within the mechanicalseal manuacturers recommendations.


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ALIGNMENT

Figure 2. Coupling Insert Damaged byMisalignment

GRUNDFOS WHITE PAPER |

Shat ailure or breakage can occur i the equip-ment is grossly misaligned.

Excessive misalignment can cause the mostdurable and best-designed couplings to wearquickly or even ail. Damage to a couplinginsert can be seen in Figure 2.

Other components with internal clearanceswithin the pump, such as impellers, wear rings,and casings can wear prematurely.

Misalignment may cause the pump and driverto operate with excessive or unusual noise.

Vibration may also be observed due to mis-alignment. However, the vibration data mustbe careully analyzed beore the blame is put

on misalignment. Misalignment may still bepresent but not seen in the vibration data iorces o the rotating equipment are acting inthe same direction to dynamically balance theunit during operation.

Some ailures that are initially attributed tophysical setup misalignment may actually becaused by other mechanical deciencies. Bentshats going unnoticed can cause the equipmentto be misaligned.

Deciencies in the coupling components, suchas a distorted hub, an eccentric hub bore, oran out-o-square hub bore may also cause theequipment to be misaligned. I the equipment isnot aligned with the consideration o tempera-ture change, the equipment may grow duringoperation and become misaligned.

Although the equipment is typically aligned orthe alignment is checked at the actory prior toshipment, proper nal alignment is the responsi-bility o the installer and user o the unit. Thosewith nal responsibility cannot allow the exiblecoupling to compensate or misalignment.

The installing technician or contractor should bemade aware o and understand the specicationand the alignment goals beore beginning thework. In addition to understanding the align-ment goals, the installation instructions or thepump, driver, and coupling should be reviewed.


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Figure 3. Alignment Tolerance Chart

I using hired contractors or alignment, a clausein their contract may be considered that requiresthem to provide initial alignment data, sot ootconditions, corrections made to the equipment,runout o the equipment shats, nal alignmentdata, and any moves made on equipment.

The equipment user must establish a specica-tion or acceptable alignment that will provide aguideline or those installing rotating equipment.A chart, similar to that shown in Figure 3, can bedeveloped to provide alignment guidelines.

The specication must include a dependableand repeatable process that will insure a reli-able installation. The alignment tolerance thatis included in the specication should considerthe shat operating speed, shat length, and theseverity o the installed service.

Included within the procedure should be inor-mation on documentation. This documentationshould include, at a minimum, alignment orms

and diagrams o the beore and ater alignmentdata. This inormation should be led with theequipment le or uture reerence.

An important part o alignment is having theproper training and the proper tools. No mat-ter what method o alignment is used, the dialindicators and lasers do not do the alignment human beings do the alignment.

With proper extensive training and practice, andthe correct tools or the job, equipment align-ment can take less than 60 minutes. Becauseo the criticality o alignment to rotating equip-ment, an organization should not skimp on costso the necessary tools and training.

ALIGNMENT TERMS

There are a ew basic terms used in alignmentthat should be reviewed. The specic terms dis-cussed in this section are important to a success-ul installation.

ALIGNMENT GRUNDFOS WHITE PAPER |


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ANGULAR MISALIGNMENT

Angular misalignment is the term used when

two shat centerlines are at an angle to eachother, as shown in Figure 4. Angular misalign-ment can occur in the horizontal or vertical planeo the shats. A typical objective is to obtainangular misalignment to less than 1.

PARALLEL MISALIGNMENT

When the equipment shat centerlines are paral-lel, but are oset rom each other, as shown inFigure 5, it is called parallel misalignment. Thistype o misalignment can also occur in the hori-zontal or vertical plane.

It is important to note that equipment shats canhave angular and parallel misalignment simulta-neously. Both must be considered or a successulinstallation.

BOLT BOUND

The term bolt bound is used to describe a con-dition that occurs during the alignment process,where the driver or pump cannot be moved anyurther. The best method to resolve this problemis to ll-weld the existing bolt hole, redrill in theproper location, and retap. This problem can alsobe resolved by removing the problem equipment

and increasing the diameter o the mountingholes in the eet.

SHIMS

Shim stock or precut shims are used to raisethe driver during the alignment process. Theproper shimming o the driver should occur onlyater the installation o the baseplate has beennalized and the connection o the piping to thepump is completed.

Typical o the baseplate manuacturers, a mini-mum o 0.125 shim under the driver eet will

allow or proper alignment. Although a mini-mum is recommended, it must be noted that toomany shims may make the installation springy.A stack o the same size o shims, as shown inFigure 6, should have ve or ewer shims o thesame size. The precut shims should be sized to tthe bolt o the equipment eet. The stack should

also have the thinner pieces o shim sandwichedbetween the thicker pieces.

The use o homemade carbon steel shim is notrecommended. In addition to the possibility orusting, the cut carbon steel may have inconsis-tency in its thickness, thereby causing a sot oot.

Precut shim o 304 Stainless Steel material is

available. These precut shims usually have thethickness measured and the exact thickness isetched on the shim. Although the thickness maybe marked on the shim, the thickness should bedouble checked beore installation.

Figure 4. Angular Misalignment

Figure 5. Parallel Misalignment


Figure 6. Precut 304 StainlessSteel Shim


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Figure 8. Soft Foot Elimination Example

Figure 7. Field Box of Precut Shim

These precuts shims may come in a convenientbox that contains many sizes, as seen in Figure7. Besides 304 stainless steel, precut shim is alsoavailable in Mylar or pumps that are in chlorineor hydrochloric acid services.

For proper use and installation o the shim, themounting pad and the equipment eet musthave a smooth surace, ree o burrs, and milledat. The shim is inserted until contact is madewith the bolt, and then moved back away rombolt to insure proper clearance.

SOFT FOOT

Sot oot is a condition that occurs when one ormore equipment eet are not rmly on the sole-plate or baseplate. With a sot oot condition, theequipment will have a tendency to move duringoperation. Sot oot should be corrected beorenal alignment and operation.

There are a number o dierent types o sot oot.It is important to identiy the type o sot oot con-dition that is present. The method to correct thesot oot depends upon the cause o the sot oot.

Using the wrong method to correct the sot ootmay intensiy the problem and make it worse.

Sot oot can initially be ound using eelergauges. Prior to tightening the equipment eetdown or shimming, eeler gauges should be usedto measure the gap under each corner o the

same oot. The readings at each location undereach oot will provide inormation about the typeo sot oot condition.

Parallel Air Gap or Short Foot

The most common sot oot condition is a paral-lel air gap, or short oot. This condition is identi-ed when there is an equal gap at all our cornerso a oot. A short oot can occur when one leg othe driver is too short, when the oot mountingpad is not in the same plane as the other(s), orthe oot has an inadequate amount o shim un-der it. I the alignment process has been started,and an accurate or consistent alignment cannotbe obtained, it is likely that there is a sot oot

condition present.To check or the parallel air gap, set up the dialindicator on a oot and loosen mounting bolt. Ithe oot moves more than 0.002, or the sot ootstandard dened by the user, the oot is consid-ered sot and needs to be corrected. This shouldbe done or all eet and documented.

The ollowing example is typical or correctingparallel air gap or short oot. Figure 8 shows aview o a motor with various parallel air gapmeasurements at each oot. It should be as-sumed that the gap shown is the same under

each corner o the oot.



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Figure 9. Dial Indicator With AlignmentFixture That Clamps to a Shaft

To calculate the amount o shim to add to com-pensate or the short oot, the sum o the smallergap values are subtracted rom the sum o thelarger gap values.

This amount is divided by two. Use 80% o thequotient as the amount o shim that should beadded under each oot to remove the parallel airgap. The equation can be shown as:

Shim to add under Foot #1 and Foot #4

DIAL INDICATORS

Dial indicators are used to measure the amounto misalignment between the equipment. A dialindicator (Figure 9) can assist in determiningalignment within 0.001. The dial indicatorscome rom the manuacturer pre-calibrated, andmust be rechecked on a regular schedule.

Shat alignment kits are available starting at ap-proximately $600.00. These kits will contain two

Shim, in the amount o 0.014, should be addedunder Foot #1 and Foot #4. Recheck by ollowingthe same procedures initially described.

Bent Foot

A bent oot is a type o sot oot that occurs whenthe bottom o oot is not coplanar, meaning thatthe oot slopes rom one corner to another. Thebest way to correct bent oot is to remove theequipment and machine the oot, the baseplate,or possibly both.

I the correction must be made in the eld, thenthe shims used in alignment must be stepped tocorrect the slope. Depending upon the size o theoot and the amount o slope in the bent oot,4-6 shims may be stepped to match the slope othe oot. Additional modications to shim mayhave to be made or the proper slope.

I rise o oot is rom the outside going in, all othe equipment eet must be machined coplanar.This type o bent oot cannot be xed in theeld. Unless the eet are machined, it will alwaysdeorm when tightened.

Squishy Foot

A squishy oot occurs when dirt, grease, paint,rust, or other oreign materials are on the shim,the base, or the equipment oot. The only solutionto squishy oot is to clean the parts and materials.



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(2) alignment rames, roller chain, two (2) dial indi-cator assemblies with swivel joints and mountingrods, tubing o varying lengths, instruction manu-als, alignment worksheets, and a sturdy carryingcase with handle. This type o kit will handle thevast majority o shat alignment situations.

When initially getting ready to use a dial indica-tor, make sure that it works properly and cantravel the ull range o the indicator.

Upon installation o the indicators and at thebeginning o the process, note the direction thatthe indicator travels. The indicator should beadjusted to start at zero (0.000).

The indicator needle traveling clockwise is

considered positive, while counterclockwise isconsidered negative travel.

During the alignment process and a ull 360sweep, the summation o the let and right sidereadings should equal the summation o the topand bottom readings.

In addition, the indicators should have read thesame reading (0.000) when it reaches the origi-nal position.

BAR SAG

Bar sag is a deection that occurs in the over-

hung indicator bar due to the bars weight andthe weight o the indicator. Because o the preci-sion that is required or alignment, the bar sagmust be compensated or.

To determine the amount o bar sag, mount theindicator on a pipe in same approach, distance,etc. as it will be mounted on equipment shat.Next, zero the indicator on top. Then roll the dialindicator 180, so that it is located at the bottom.Read the indicator.

During the alignment process, this bar sagamount must be included in your alignment

calculations. Instead o zero on the top o the dialindicator, dial in the positive value o the bar sagreading. During the alignment process, the dialindicator should read zero when rolled to bottom.

ALIGNMENT BASICS AND PRELIMINARYCHECKS

There are a number o dierent tasks to com-plete and check prior to doing the actual align-ment. The preparation or alignment can be asimportant as the alignment itsel. Approximately85% o the time spent in aligning equipment iswith preliminary checks, repositioning the equip-ment and post alignment documentation. Thealignment basics and preliminary checks apply toall alignment methods.

To insure accuracy and speed o the alignment,the equipment should be aligned three times.The rst time should be during the installation

process (preliminary).Next, the equipment should be nal aligned aterit is piped and beore the start up o the equip-ment. Finally, the alignment should be checkedwhen the equipment is hot, ater running or atime.

Saety o personnel is important during any parto the alignment process. The rst step is tolock out and tag all driver controls and isolationvalves. Other saety regulations required at theinstallation site must be ollowed.

As people are doing the alignment o the critical

equipment, it is imperative to make sure thatthey have the proper training to complete preci-sion alignment.

A properly trained technician in the undamen-tals o alignment will not only provide a qualityalignment, but also should do it in a timely ash-ion, exceed the recommended standards, and doit right the rst time.

The tools used in alignment are also important. Iusing dial indicators to align, calibrated indica-tors are required with the additional equipmentused to hold the indicators in place. Laser align-

ment kits are typically complete with all thenecessary alignment diagnostic equipment.



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Additional alignment tools include a straight edge,a eeler gauge and a taper gauge. O course, thenecessary tools to loosen and tighten bolts, cleanparts, and move equipment are also required.

Inormation about the equipment should alsobe reviewed beore the alignment begins. Thisincludes the recommendations o the manuac-turers, as well as technical inormation on theequipment that may have been taken previously.

Preliminary checks o the equipment, includingsot oot, pipe stress, and equipment conditionshould be taken to insure that these would notcause the equipment to become misaligned.

Measurements o the shat positions should be

taken. The pump and driver shats should bechecked or runout. The shat runout should notexceed 0.002 T.I.R. The clearance in bolt holesin equipment eet should be adequate to allowmovement o the equipment.

Pipe stress can have as much or more aectthan sot oot on misalignment. When installingpiping in a system, the piping must start at thepump connections and be erected away rom thepump. Pipe stress on a pump can prevent a pumprom being properly aligned. This problem can beprevented during the original construction.

A preliminary alignment check should be donebeore grouting to ensure alignment can beobtained. This can be done during abrication orat the installation site. The equipment eet mustbe ree o dirt and scale. Conrm that the drivercan be adjusted by being lowered or moved sideto side. The check must be made with the equip-ment at ambient temperature. The pump mustalso be disconnected rom all pipe during thispreliminary alignment check.

The pump and driver must be installed on a goodbaseplate and the proper oundation. Final align-

ment should be completed only ater the grout-ing has cured during the unit installation. This isto ensure that no changes have occurred duringthe grouting process.

The pump and driver coupling hubs should thenbe installed with the proper gap per the cou-pling manuacturers installation instructions.

Each shat must turn reely with hubs installedon the shat. Conrm that the ace and outsidediameters o the coupling hubs are square andconcentric with the coupling bores.

Spacer type couplings are aligned with thespacer element removed rom the coupling.Gear type couplings are aligned with the samealignment methods, except that the couplingcovers must be moved back out o the way othe alignment work.

A preliminary check o the angular measuremento the coupling gap should be made with a eeleror taper gauge, or other tool. In lieu o a eelergauge, a measurement o the distance can be

taken between the hubs.The clearance that is being conrmed is shownin Figure 10. For this preliminary check, do notrotate either shat. The check should be made at90 intervals in our places, typically at 0, 90,180, and 270. I possible, adjust the alignmento the equipment until within 0.002 T.I.R. or lessat all our locations.

The preliminary check o the parallel alignmentis next. A straight edge can be used to checkparallel oset as shown in Figure 10. Again, donot rotate either shat, and check the parallel

alignment in our places at 90 intervals. Checkthe alignment on the horizontal axis rst, thenthe vertical axis.

During preliminary alignment or nal alignment,always recheck alignment ater any alteration.Movement in one direction may alter alignmentand modications made in another direction.

The parallel oset should be rechecked i any ad-justments are made to the angular alignment. Theangular alignment should be rechecked ater anyadjustments are made to the parallel alignment.

Ater the preliminary alignment is completed,

the piping, ductwork, etc. can be attached. Anystress ound at the pipe connections should beremoved. The horizontal stress in the pipingshould be relieved rst. This can simply be doneby loosening all bolts at the pump anges andlooking or movement. Make adjustments to pipehangers and supports as necessary.



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Figure 10. Preliminary Alignment Checks

the shat separation between the equipmentis greater than 50% o the outside diameter inwhich the dial indicators contact the couplinghub rim. A summary o each o these methods isdescribed below.

RIM AND FACE METHOD

The Rim and Face alignment method is typicallyused when it is not possible to rotate both shatsor i there are space limitations.

A disadvantage o this method is that the dialindicators are running on the surace o thecoupling hub. The hub may have aws, such assurace deects or eccentricity that may makealignment difcult.

The goal or Rim and Face alignment is 0.002T.I. R. or less when the pump and driver are atoperating temperature.

The vertical piping stress should be relieved next.Make any modications to relieve the horizontalor vertical stresses in stages. The stresses are onlypartially relieved the rst time. Additional modi-cations should ollow.

The nal alignment o the equipment is doneater the grout is set, the piping is in place, and thebaseplate bolts tightened to the oundation.

Although the coupling installation instructions mayallow or greater misalignment, the alignmentshould be within 0.004 in all directions, or as re-quired by the manuacturer or user specication.

Methods or nal alignment include Rim and

Face, Reverse Dial Indicator, and Laser. The Rimand Face method can be used with the simplesto installations.

It is recommended that the Reverse Dial Indica-tor or Laser Alignment methods be used when



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Figure 11. Rim and Face Indicator Setup

This method will obtain an oset reading on theoutside diameter (rim) o the driver coupling huband an angular reading at the coupling hub ace,and will use these readings to mathematically orgraphically adjust the driver to the required loca-tion or alignment.

Figure 11 provides a view o the set up o the Rimand Face Method. The indicator bar can also bemounted on the pump shat i room allows.

Figure 12 shows the dimensions and readingsthat are required or alignment using the Rimand Face Method. Following are denitions usedwith the Rim and Face Method.

Figure 12. Rim and Face Method Layout

ALIGNMENT GRUNDFOS WHITE PAPER | 1


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Equation 2. Inboard Driver Movement

F x BIB Movement = - R

D

F x AOB Movement = - R

D

Equation 3. Outboard Driver Movement

DEFINITIONS

IB Inboard (towards pump) driver eet

OB Outboard (away rom pump) drivereet

A The horizontal distance rom the rimdial indicator location to the cen-terline o the bolt or the outboarddriver eet

B The horizontal distance rom the rimdial indicator location to the center-line o the bolt or the inboard drivereet

D The diameter o the dial indicator

sweep on the pump coupling hubace

TIR Total Indicator Runout

F The TIR o the pump coupling hubace

R The TIR o the pump coupling hub rim

Two ormulas are used in determining themovement required o the driver. Equations 2and 3 dene the adjustments needed or theinboard (IB) and outboard (OB) driver locations.These ormulas will be used or horizontal

movement, using the horizontal dial indicatorreadings, and or the vertical movement, usingthe vertical dial indicator readings.

When considering horizontal movement o thedriver, the movement to the let or right is basedon the view rom behind the driver, lookingtowards the pump.

RIM AND FACE ALIGNMENT PROCEDURE

Following is the procedure to align equipmentutilizing the Rim and Face Method.

1. Eliminate Sot Foot

a. Determine i a sot oot conditionis present. Follow the procedures toremove the sot oot condition i itexists.

2. Conrm Bar Sag

3. Align Driver rom Let to Right

a. Set up the dial indicators as shown inFigure 11.

b. Record measurements A, B and Das shown in Figure 12.

c. Zero the rim and the ace dialindicators to 0.000 at the 9 oclockposition o the couplings, as viewedrom the motor end. Reerence the dialindicator diagram in Figure 13.

d. Rotate the indicators on the driver

shat 180 until they are in the 3 oclockposition.

i. Note the direction o the movemento the needles on the indicators.

ii. Clockwise movement o the needleis considered positive (+).

iii. Counterclockwise movement o theneedle is considered (-).

e. Determine the amount o horizontalmovement o the IB and OB o the driver

i. Make adjustments to the readingswith respect to the Bar Sag.

ii. Utilize Equation 2 and Equation3 to determine the amount omovement.



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Figure 13. Rim and Face Alignment Worksheet

Inches Horizontal DriverMovement

Positive (+) = LeftNegative (-) = RightA = 26

B = 16 IBHorizontal = 0.026

C = 4 OBHorizontal = 0.046

Vertical DriverMovement

(Add or Remove Shim)

Positive (+) = AddNegative (-) = Remove

IB = Inboard IBVertical = -0.020

OB = Outboard OBVertical = -0.035

(FaceValue)xBIBMovement= (Rim Value)

D

(FaceValue)xAOBMovement= (Rim Value)

D



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iii. A positive (+) value o the IBHorizontal

or OB

Horizontalrequires the driver to be

moved to the let, as looking towardthe pump rom behind the driver.

iv. A negative (-) value o the IBHorizontal

or OB

Horizontalrequires the driver to

be moved to the right, as lookingtoward the pump rom behind thedriver.

. Make adjustments to the driver. Tightenall motor bolts using a torque wrench.The same torque on all mounting boltsreduces the inuence o deormities inthe motor eet.

4. Align Driver Verticallya. The dial indicators should still be set up

as shown in Figure 11.

b. Zero the rim and the ace dialindicators to 0.000 at the 12 oclockposition o the couplings, as viewedrom the motor end. Reerence the dialindicator diagram in Figure 13.

c. Rotate the indicators on the drivershat 180 until they are in the 6 oclockposition.




d. Determine the amount o verticalmovement o the IB and OB o the driver

i. Make adjustments to the readingswith respect to the Bar Sag.

ii. Utilize Equation 2 and Equation

3 to determine the amount omovement.

iii. A positive (+) value o the IBVertical

or OB

Verticalrequires the driver to be

raised, utilizing additional shims asrequired.

iv. A negative (-) value o the IBVertical

or OB

Verticalrequires the driver

to be lowered, by removing theunnecessary shims as required.

e. Make adjustments to the driver. Tightenall motor bolts using a torque wrench.The same torque on all mounting boltsreduces the inuence o deormities inthe motor eet.

5. Recheck the horizontal alignment to insurethat all alignments are acceptable.

6. Document the nal readings on analignment orm or data sheet, and leaccordingly.

REVERSE DIAL INDICATOR METHOD

The Reverse Dial Indicator method o alignmentis the most common type o alignment, and isrecommended or most all installations.

The reverse dial indicator method uses therelative measurement o the centerlines o twoopposing shats. This method acquires twoindicator readings across the coupling.

These readings are used to mathematically orgraphically assist in determining the requiredadjustments and shimming or each oot o the

driver, or moveable unit.

Measurements will be taken in the horizontaland vertical planes o the shats. The indicatorswill be set up in a similar ashion as shown inFigure 14.

One indicator is mounted on each shat andmounted 180 opposite each other. Whenreading the indicators, it is important to watchthe direction rom zero that the needle travels.

Travel to the right, or greater than zero (0), isconsidered positive (+). Travel o the needle to the

let, or less than zero, is considered negative(-).As graphing is one method in determining thealignment o the equipment in the ReverseDial Indicator method, it is important to haveconsistency between the installation, picturesand the graph paper.



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For this article, the moveable (driver) unitis considered to be on the right side o theinstallation, pictures and graph paper.

Plain graph paper can be used or plotting theinormation. A worksheet, as shown in Figure 15,

Figure 14. Reverse Dial Indicator Method

Equation 4. Slope

[Stationary Unit Reading + Movable Unit Reading]m(slope per inch) =

2A

IB Foot ChangeVertical

= [m x (A + B)] + (Stationary Unit Reading)

Equation 5. IB Foot Vertical Adjustment

OB Foot ChangeVertical

= [m x (A + B + C)] + (Stationary Unit Reading)

Equation 6. OB Foot Vertical Adjustment

can be set up to show the installation and allowor graphing the solution.

The slope method is used to determine therequired adjustment. The three equations beloware used in the calculations o the adjustments.



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REVERSE DIAL INDICATOR ALIGNMENTPROCEDURE

Following is the procedure to align equipmentutilizing the Reverse Dial Indicator Method. Notethat some steps are identical to the Rim and FaceMethod.

1. Eliminate Sot Foot

a. Determine i a sot oot condition ispresent. Follow the procedures to removethe sot oot condition i it exists.

2. Conrm Bar Sag

Figure 15. Reverse Dial Indicator Alignment Worksheet

Horizontal Vertical - I Horizontal change is negative, move LEFT

Moveable Front -0.005 0.011 - I Horizontal change is positive, move RIGHT

- I Vertical change is negative, REMOVE shims

Moveable Back -0.007 0.025 - I Vertical change is positive, ADD shims

3. Align Driver rom Let to Right (horizontal)

a. Set up the dial indicators as shown inFigure 16.

b. Record measurements A, B and Cas shown in Figure 16.

c. Using graph paper with square grids,utilize the width o a square as 1 inch,and locate the dial indicator locationsand moveable eet on the shat lineaccordingly.



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d. Zero the rim and the ace dialindicators to 0.000 at the 9 oclockposition o the couplings, as viewedrom the motor end. Reerence the dialindicator diagram in Figure 15.

e. Rotate the indicators on the drivershat 180 until they are in the 3 oclockposition.



iii. Counterclockwise movement o the

needle is considered (-).

. Determine the amount o horizontalmovement o the IB and OB o the driver.

i. Utilizing the Reverse Dial Indicatorgraph, mark the points that are hal

Figure 16. Reverse Dial Indicator Setup

the indicator readings under theirpositions. A vertical square shouldbe considered 0.001.

ii. Draw a line connecting these twopoints, and extending to a pointbelow or above the moveable eetpositions.

iii. The graph will show how much theeet will be required to move, basedon a vertical square being considered0.001.

iv. The graphed points below the shatposition (+) will require the eet to

be moved to the right.v. The graphed points above the shat

position (-) will require the eet to bemoved to the let.



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g. Make adjustments to the driver. Tightenall motor bolts using a torque wrench.The same torque on all mounting boltsreduces the inuence o deormities inthe motor eet.

4. Align Driver Vertically

a. The dial indicators should still be set upas shown in Figure 16.

b. Zero the rim and the ace dialindicators to 0.000 at the 12 oclockposition o the couplings, as viewedrom the motor end. Reerence the dialindicator diagram in Figure 15.

c. Rotate the indicators on the driver

shat 180 until they are in the 6 oclockposition.




d. Determine the amount o verticalmovement o the IB and OB o thedriver. Note that Equations 4, 5, and 6

are used in calculating the slope and therequired shim removal or addition. Thesteps are similar to those or horizontalmovement.

i. Utilizing the Reverse Dial Indicatorgraph, mark the points that are halthe indicator readings under theirpositions. A vertical square shouldbe considered 0.001.

ii. Draw a line connecting these twopoints, and extending to a pointbelow or above the moveable eet

positions.iii. The graph will show how much

the eet will be required to move,based on the a vertical square beingconsidered 0.001.

iv. The graphed points below the shatposition (+) will require shim to beadded.

v. The graphed points above the shatposition (-) will require shim to beremoved.

e. Make adjustments to the driver. Tightenall motor bolts using a torque wrench.The same torque on all mounting boltsreduces the inuence o deormities inthe motor eet.

5. Recheck the horizontal alignment to insurethat all alignments are acceptable.

6. Document the nal readings on an

alignment orm or data sheet, and leaccordingly.

LASER ALIGNMENT METHOD

The laser alignment method is considered aprecision-based perormance technique thatprovides a aster, more accurate way to alignequipment.

It is ideal or alignment o equipment over longdistances, and it is less prone or user error. Becauseo the range o technology between variousmanuacturers, the steps or laser alignment are

not discussed in detail in this article.

The laser alignment equipment consists o atransducer system. Figure 17provides a view o a

Figure 17. Setup of Laser Alignment Equipment



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laser alignment system installed on a pump andelectric motor. The system contains a laser diodeand position sensor on one mounting bracket.

The diode emits a pulsating, non-hazardous,laser beam that is directed at the oppositebracket. The opposite bracket contains a prismthat redirects the laser beam back to the positionsensor. Like other shat alignment techniques,the shats are rotated to determine the verticaland horizontal readings or angular and parallelmisalignment.

The shat positions and readings are automaticallyprovided to a small computer. The computer thencalculates the relative movement required at the

eet o the moveable machine. Figure 18 provides aview o the diagnostic computer.

A major advantage o the use o laser alignmentis the precise measurement o misalignment.Laser alignment can detect misalignment to0.00004. In addition, with the use o laseralignment, bar sag concerns are eliminated.

However, there are drawbacks and limitationsto the laser alignment method. Laser alignmentequipment typically costs more than $10,000.Service companies or those companies withmany pumps or large pumps are the primary

buyers o laser alignment equipment.The environment in which the laser alignmentequipment is used is also a limitation. Theatmospheric temperature must be between32 and 131 Fahrenheit or the use o laseralignment. The environment must also be ree osteam, dust, or air currents.

These detractors will prevent the reading o thelaser beam properly. However, it is possible touse a plastic pipe to shield the beam rom thesteam, dust, or air currents.

FINAL CHECKS AND WORK CLOSEOUTAter the equipment has been aligned, someadditional tasks and checks should be perormed.

Make sure that each shat turns reely with thecoupling hubs installed.

Figure 18. Laser Alignment Diagnostic Equipment

The saety equipment should be removed andthe equipment energized.

The driver should be bumped to check orproper rotation.

Reinstall the saety precautions and completethe assembly o the coupling per theinstallation instructions.

Rotate the coupled shats to ensure they turnreely.

Install the coupling guards per OSHA orapplicable requirements.

The saety equipment should be removed andthe equipment energized.

Once the pump is ready to operate, the pumpand piping that has been drained should belled. As the pump and the system piping islled, observe or any piping distortion due toimproperly supported piping. Poorly supportedpiping may cause misalignment.

Ater the piping is installed, the pump unitis operated under normal conditions and isthoroughly warm, stop the pump unit to recheckalignment while it is warm. This also ensuresthat there is no additional pipe strain.



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I additional alignment is required o morethan 0.002 rom the pipe ree condition, theadditional piping strain should be corrected.Additional discussion on piping installation canbe ound in another article.

For high energy and petroleum pumps, the pumpand driver eet are drilled and doweled at twolocations, near the thrust bearing end, aterthe nal alignment is complete and meets thespecications.

Documentation o the alignment is important tothe installation and operation o the equipment.Make a record o the nal alignment tolerance onan alignment orm or data sheet. This should be

placed in the equipments history le. This pro-vides not only proo o nal condition, but allowsa starting point and historical data or the uture.

For work done in the uture, this inormation willallow or the alignment to be done quicker andsmoother, saving set up time. In will also provide abasis to allow or measurement o operational time.

Reporting or recording sheets can be developedto include inormation on sot eet, pipestress and strain, coupling and shat runouts,installation conditions such as bolts being oundloose, and speciying the initial, desired, and nal

alignment inormation.The sheet should also provide a location oridentication o the persons completing the workto be documented. This places responsibilityo quality work on individuals, and provideslearning opportunities i a ailure occurs.

Reported data allows or troubleshooting androot cause analysis o equipment ailures. Thedata can be used to compare the as discoveredcondition and the as completed condition. Thiscan be particularly useul or equipment withchronic abnormal behavior.

Another useul tool or recording data are digitalphotos. Pictures o the shat, coupling, base, andoundation conditions can be stored. These couldbe used in the uture during set up to determineany special needs or how the installation was let.

Although alignment should not be scheduled tobe rechecked with the requency o preventative

maintenance procedures, it should be recheckedwhen observations are made in regards tothe settling o the base, oundation, or soils,changing o the piping system, process changes,or seasonal temperature changes.

For a new installation, the alignment should bescheduled to be rechecked 3-6 months ater theinitial installation and alignment.

SPECIAL SERVICES

HIGH TEMPERATURE

Abnormally high temperatures can aect the align-ment o a pump and its driver. These temperaturechanges can be caused by riction in the bearings or

change that occurs with a process liquid.

The thermal growth can occur on pumps in ahot service, such as in the petroleum industry orpower plants. When the pump is the equipmentin the hot operation, the pump is set and alignedlower than the driver. This is called cold setting.This will allow or the thermal growth.

The pump manuacturer will typically have a chartavailable to assist in the proper alignment. Themanuacturers recommendations should alwaysbe ollowed or the exact piece o equipment.

I the driver is the high temperature equipment,such as with a steam turbine, the driver shatshould be set lower than the pump shat to com-pensate or vertical expansion o that equipment.Ater the equipment reaches normal operatingtemperatures, alignment should be veried.

VERTICAL PUMPS

For services located in process plants, alignmento vertical pumps must be considered. This isespecially true i the driver thrust bearing carriesthe load o the driver and the pump.

Because o the importance o the driver thrustbearing in this pump and driver conguration,accurate radial and angular alignment betweendriver and the pump is essential.

As part o the precision alignment process overtical pumps, the driver shat runout andconcentricity with the mounting t must be



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reviewed. This should always be done prior to theassembly or reassembly o the driver on the pump.

As a rule o thumb, the process industry recom-mends that the shat runout and the concentricityo the mounting t should be within 0.002 totalindicator runout (T.I.R.) per oot o rabbet t diam-eter o the motor mount. In addition, the mount-ing ace must be perpendicular to the shat within0.002 T.I.R. per oot o rabbet t diameter.

The driver shat runout should not exceed 0.002T.I.R. or 0.001 T.I.R. per inch o shat diameter,whichever is greater. For a solid shat motor, theshat end oat must not exceed 0.010 T.I.R., and0.005 T.I.R. is recommended i the pump has a

mechanical seal.These requirements may be more stringent thanthe National Electrical Manuacturers Association(NEMA) [1], but they are essential or solid shatdrivers and 2-pole motor speeds. Typical NEMAtolerances are acceptable or deep well turbinesand 4-pole rpm or lower speeds.

Some manuacturers and models do not usea rabbet t between the pump and driver, butalign the driver shat to the pump stufng box.This practice is also acceptable to use i therabbet t is not concentric with the shat.

When nal aligning vertical pumps, the drivershould be within 0.0005 per inch o stufng boxbore or pumps with mechanical seals, and 0.001per inch o stufng box bore or packed pumps.

For large motors, the use o jacking bolts may berequired to move the motor.

ALIGN EQUIPMENT TRAINS

There are occasions when more than twopieces o equipment are installed in a trainor a service. An example would be a pump,gear reducer, and a driver. The alignment o a

train can become more demanding due to anadditional variable.

It is important to understand the equipmentinvolved. As previously mentioned, theinstallation and operation manuals or all o

the equipment in the train should be reviewed.A consistent procedure should be developed toprovide a sequence o alignment that will beused or each time the equipment is aligned.

A guideline used in the industry is the xing othe middle piece o equipment, usually the gear-box, and move the other equipment in otherwords, start in the middle and move outward.Rough readings should be taken to insure noneo the equipment would be bolt bound.

I the equipment is bolt bound, the position oall equipment should be graphed to determineoptimum position. This technique is acceptablei piping has not already been installed. I

the piping is already installed and xed, thenadditional care should be taken to insure thatpipe stress is not put on the pump.

REFERENCES

1. National Electrical Manuacturers Association(NEMA), 1300 North 17th Street, Suite 1847,

Rosslyn, VA 22209; http://www.nema.org.

ACKNOWLEDGEMENTS

Figures 2, 6, 7, 9, 17, and 18:Diagnostic Solutions, LLC.



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Being responsible is our oundatioThinking ahead makes it possib

Innovation is the essenc

L-CBS-WP-01Rev.03/09(US)

USAGRUNDFOS Pumps Corporation17100 West 118th TerraceOlathe, KS 66061Phone: (913) 227-3400Teleax: (913) 227-3500

CANADAGRUNDFOS Canada Inc.2941 Brighton RoadOakville, OntarioL6H 6C9Phone: (905) 829-9533Teleax: (905) 829-9512

MEXICOBombas GRUNDFOS de Mexico S.A. de CBoulevard TLC No. 15Parque Industrial Stiva AeropuertoC.P. 66600 Apodaca, N.L. MexicoPhone: 011-52-81-8144 4000Teleax: 011-52-81-8144-4010

USAPACO Pumps National HeadquartersGrundos CBS Inc.902 Koomey RoadBrookshire, TX 77423Phone: (800) 955-5847Teleax: (800) 945-4777

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