Centac Vibration Procedure%2Epdf

8/22/2019 Centac Vibration Procedure%2Epdf

1/20

Table of Contents

Topic Page

Vibrations solution process / scope 1Vibration symptoms 1Actions for vibration related field problems 2

Table Page

1 Vibration symptoms 13 Actions for field related vibration

problems3-7

Appendix PageA Preliminary data requirements 8-9

B Preliminary investigation,vibration descriptionrequirements, and likely causesof high vibration

10-14

C Component damage assessment 15-18


2/20

1

A Vibrations Solution Process

Scope:

The scope of this solution process is limited to vibration related problems. Theseproblems have root causes that directly lead to excessive vibration in the compressorrotor stages or in the bullgear system. It does not relate to vibration related problemsthat may affect other systems or components such as the driver, baseplate, etc.

Vibration Symptoms:

The following symptoms are accepted as being sufficient to require that the VibrationsSolution Process be followed. If one or more of the listed symptoms are not present; but,vibration is still suspected as being excessive; consultation with aftermarket servicesupport reps should be made. There is no criteria addressing an unacceptable rate of

change of vibration. However, unusual changes in the vibration behavior should bereported to the appropriate aftermarket representative at the factory.

Table 1

1 During shop testing with the fully warmed up compressoroperating at steady load, with the probes and controlsfunctioning properly, the stage vibration reading at the end ofthe mechanical test period exceeds the shop acceptancelevel. Or, if the vibration level exceeds the shutdown limitsany time during the test. Or, if the vibration level repeatability

exceeds the alarm limit.

2During compressor commissioning, the vibration signalsexceed the field acceptance limits with the compressorwarmed up and operating at steady load. Or, if the vibrationlevel exceeds the shutdown limits any time during the test.Or, if the vibration level repeatability exceeds the alarm limit.

3 After commissioning and during warranty; during startup,steady load operation, or normal shutdowns; the stagevibration signals repeatability exceed the alarm values.

4 The compressor has experienced a severe rotor contactwithin the gearcase/stage area with or without an indicationof vibration shutdown in the control panel.


3/20

2

Actions For Vibration Related Problems:

If any of the symptoms listed in Table 1 are present, theactions outlined in Table 3 are appropriate. Note that actionsare presented for different time periods of the solutionprocess. These include:

1. Prior to opening the unit for inspection or repair

2. Problem Evaluation3. Disassembly4. Repair and Re-assembly5. Re-start6. Solution Follow Up


4/20

3

Table 3.

Actions For Field Related Vibration Problems

Prior to opening compressor for inspection or repair

Responsibility Action Comments/Suggestions

ServiceTechnician

Collect preliminary data (seeAppendix A), and provide copy tocustomer service engineer andreliability engineering

Data includes generaldescription of compressor, site,problem, customer comments,machine history, application,data logs, and initial machineinspection.

ServiceTechnician

Check compressor system forthose specific causes of vibrationthat can be investigated prior to

opening the compressor. And,identify and/or refine thedescription of the vibrationsymptoms. See Appendix B.

This is where available CMCevent and analysis logs arerecommended.

CentacCustomerServiceEngineer

Update preliminary data toinclude shop related information.See Appendix A. Open/create aservice file for the machineproblem in question.

ServiceTechnician with

Centac CustomerService Engineer

Collectively decide on the nextsteps to be taken.

The Customer ServiceEngineer can obtain advice

from reliability engineeringand/or advance engineering.


5/20

4

Table 3.

During disassembly of the compressor


ServiceTechnician Assure a controlled disassemblyprocess which collects andpreserves data that may beneeded to determine the rootcause of the problem

Investigate/report on air/oil sealrubs, diffuser rubs, loose/bentparts, gear mesh errors, FOD,assembly or set up errors,varnishing, fretting, and etc.

ServiceTechnician

Document parts damage andother findings pertinent to theproblem. Provide inspection datato Centac Customer ServiceEngineer.

See Appendix C for specificdata to secure and to report onas part of the disassemblyprocess.

ServiceTechnician andCentac CustomerService Engineer

Discuss findings to determinenext steps to be taken. If noadditional help is needed;establish action plan, documentplan and apparentproblem/solution, and proceed tocompressor repair and rebuildstep. If help is required toestablish the problem cause andsolution, or if an earlier action didnot solve the problem, proceed to

the problem evaluation step.

Next steps include possiblereplacement parts, added helpat site, need for problemevaluation phase, etc.

All parts must be returned toeither Davidson/ Vignate forevaluation.


6/20

5

Table 3.

Problem Evaluation


AftermarketCustomerService Engineer

Consult with Reliability/CustomerService manager and the ChiefEngineer to establish need andpriorities for a root causeanalysis. Also, take necessarysteps to contain the problem andto quickly address safety issuesearly. May also request parts tobe returned for inspection.

AftermarketCustomer

Service Engineer

If root cause analysis is notneeded; determine action plan,

document plan, and proceed torepair and rebuild step. If rootcause analysis is needed,request Oversight Committee toschedule and assign root cause.Oversight Committee:Engineering managers, Q/Amanagers, A/M manager andService managers.

OversightCommittee

Assign, schedule, and direct rootcause team.

Root Cause TaskTeam Determine root cause of theproblem. Document results.Advise Oversight Committee andAftermarket Customer ServiceEngineer of the root cause andrecommended (and possiblealternative) solution.

OversightCommittee

Approve, schedule, and assignthose actions that are needed toimplement the corrective action.

Oversight

Committee

Assure that the approved

corrective actions areimplemented, monitored, anddocumented.


7/20

6

Table 3.

Compressor Repair and Re-assembly

Responsibility Action Comments/SuggestionsAftermarketCustomerService Engineer

Determine and communicate toservice technician replace,refurbish, or reuse of repaircomponents.

ServiceTechnician

Follow Centac service practicesand document repair in X-Sitereport.

CTC ServiceManager

Audit compressor repairs. Adjustrepair requirements as required.Report progress to Aftermarket

Customer Service Engineer.

Table 3.

Startup

Responsibility Action Comments/SuggestionsService

TechnicianFollow Centac service practices,start and monitor compressoroperation making systemadjustments as are required.Document start-up results in theX-Site report.


Assure that the problem hasbeen resolved.


8/20

7

Table 3.

Solution Follow-up

Responsibility Action Comments/SuggestionsServiceTechnicianSupervisor

Release service technician fromsite when customer agrees thatthe initial problem has beenresolved.


Insure that the factory service fileis complete. The file must containthe units repair history, startupand operational data.

OversightCommittee

Monitor results. Verify if problemis fully resolved and that

corrective action was effective.Enter data into the electronicservice problem data file.

Electronic file/program needsto be designed, written, and

implemented.

AftermarketReliabilityEngineer

Assure submission and followprogress of ECRs for design,manufacturing, or other processchanges that the solutionrequires

Division needs an ECR likeprocess for manufacturing andother process changerequests.

OversightCommittee

Review problem solvingprocesses and initiates changesin the process if they are

required.


9/20

8

Appendix APreliminary Data

1. General Description of Compressor

CustomerLocation

Appl ication

Compressor Model

Serial Number

Hours

Pressure

Horsepower

Driver Type

Driver Size

Driver Supplier# of Starts

2. Problem Description

Date

A. Init ial Complaint Symptom(s)

Yes No

High Vibration How High

Changing/Fluctuating Vibration Describe below

Upward Trending Vibration Describe below

Vibration Higher Than SimilarMachines at Same Site

Explain below

Unusual Noise Describe below

Found During Routine Maintenance

Other

B. When is Problem Seen

Yes No Yes No

Cold Start Hot Start

Unloaded Loaded

Start Up Coastdown

C. Condition of Compressor Now

D. Other


10/20

9

Appendix A Preliminary Data

3. Machine History

A. What problems has machine had in the past?

B. What actions were taken?

C. What were the results of these actions?

D. Field Vibration, Prior to Problem

Pk-Pk (mils) Vibration

1X (mils) Vibration

Yes NoSpectrum Measured

Acceleration Signature Measured

CDS Taken

Other

E. Field, Current With Problem

Pk-Pk (mils) Vibration

1X (mils) Vibration

Yes NoSpectrum measured

Acceleration Signature Measured

CDS TakenOther

F. Design and Appl ication

What operation was compressor designed for?

How is the compressor actually being operated?

G. Recent Operation Logs

H. Initial Machine Inspection

Results of check of possib le problem causes (see Appendix B)


11/20

10

Appendix B

Before the compressor is restarted or opened for fur ther investigationand/or repair, it is important to:

1. Identify and refine the description of the high vibration symptoms.

2. Check the compressor system for those specific causes of vibration thatcan be investigated prior to opening the compressor.

3. Obtain all signi ficant data that may otherwise be lost or unavailableshould the compressor system be operated, re-started, or opened forinspection.

A. Prel iminary Investigat ions that should be made: Initial Date1. Check for areas of major damage that precludes

continuing runn ing or from re-starting the compressor.2. Slow roll the bullgear

3. Confirm the impeller clearances.

4. Check the instrumentation for proper operation andadjustments.

5. Visually check the oil for dirt, discoloration, water,air, or other contaminates.

6. Visually check the seal area of each stage using theseal vent line ports.

7. Confirm the available oil pressure with thecompressor stopped using the pre-lube pump.

8. And, check for any other reasons that thecompressor should not be run.

B. Provide a complete description of the timing and the duration of thehigh vibration signals.

When Yes No1. Start up

2. Unloaded

3. Loaded

4. Coast-down

5. Surge

6. Other (Describe)Duration: Yes No1. Continuous, all the time

2. Transient

3. Periodic, cyclic

4. Trending over a long period


12/20

11

III. Likely causes of high vibration signals.

Symptomof High

Vibration

LikelyMechanism

LikelyRoot Cause(s)

Tests/Checks toMake. Will assist to

confirm root cause.High 1XVibration

Loss ofBalance

Dirt build up on impeller

Nose bolt has backed out

Foreign object damage toimpeller

Broken or cracked vane onimpeller

Attachment has loosened

Loose nose cone, washer, orbolt

Loose thrust collar Impeller not locked during

assembly

Excessive use of Loctite onrotor bolt

Impeller interfering with pinioncsink

Surface damage to polygon

Faces of impeller/pinion notsquare.

Hand work used on

attachment .

Rotor not balanced tospecification

Pinion gear runout

Loss of bearing dampeningcan induce an increase of 1X,easily found with run down.

Take ADRE orother vibrationspectrummeasurement toconfirm 1X.Spectrum shouldbe taken duringstart-up, atspeed/loaded,and during coast-

down.

Any form ofhighvibration

Excessiveloads onjournal

bearings

Misapplication (surge, air toocold, oil too cold, etc).

Excessive piping strain on

heads, gearcase.Usually noneuntil impellertouchesdiffuser, thenmultiplefrequencies

Excessiveloads onthrustbearings

Misalignment of thrustbearing during installation.

Thrust collar not square topinion axis/thrust bearing.

Thrust face designinadequate for application.

Accelerometermeasurement ofaxial vibration.

Confirm if surgepressure hasdeteriorated.


13/20

12

1X orsubsychroun

ous orvibrationincreaseswhen load orunloadcompressor

FaultyJ ournal

Bearings

Damaged bearing

Bearings not manufactured

to required tolerances Bearing design not correct

for the application

Vibration signallevel when

loaded/unloaded Spectrum loaded,

unloaded, coast-down.

1X orfraction ofrunningspeed

0.4X

Oil/seal rubs

Oil whirl/whip

Contaminate in seal area

Loose or sticking seal

J ournal surface pitted, dirty,etc.

Undersize seal

Bearings oil whirl/whip orseal out of tolerance.

Air/oil seal leaksmay indicatedamaged seal.

Spectrum loaded,unloaded, coast-

down. View shaft

through seal ventand check fordiscoloration inseal area.

Erratic, or 1Xorsubsychrounous orvibration

increaseswhen load orunloadcompressor

Oilinterruption

Check CMC log

Inspect thrustbearing surfacesfor damage.

Varies Faulty Oil Oil is dirty

Oil contaminated with water Visual check of oil

Oil sampleanalysis

Erratic signalor includeslinefrequency

FaultyVibrationInstrumentation

Faulty component

Faulty probe setting

Electrical interference

Check gap setting

Swap leads

Check power

supply totransmitters

Look for source ofexternalinterference suchas contacts, cellphones, etc.


14/20

13

1X, 3X Rotor run-out,HERO

mechanical run-out of thepinion journal

Electrical run-out of thepinion journal

Polygon distorts journal in 3-lobe shape

Slow roll vibrationmeasurement

Vibrationmeasurementsduring coast-down

Vibrationincreaseswhen loadcompressor,or signalmay showside-bands

about gearmeshfrequency, orvibrationmay changeasambient/oiltemperatureschange

FaultyGearcaseBores,Rotors,Gears, etc.

Assembly Errors, Alignment,etc.

Faulty Gearcase Bores,Rotors, Gears, etc.

Varies, butoften

vibrationchanges ascompressoris loaded orunloaded

WrongBearing

Wrong Bearing Installed Spectra test,unloaded, loaded,at surge, andduring coast-down.

High sub-synchronousvibration

BearingInstability

Oil too hot, wrong viscosity

Stage is too lightly loaded

Bearing bore is oversized

Spectra test,unloaded, loaded,at surge, andduring coast-down

High super-synchronousvibration, 3Xetc.

Loose, bent,distorted rotor

1. Loose, bent, distortedrotor



15/20

14

Randomfrequencies,or 1X

Gear MeshErrors

Damaged or worn piniontooth

Damaged or worn bullgeartooth

Casingaccelerometermeasurements


1X, 3X, or4X

BearingVarnish

Incorrect or contaminated oil

Operating temperature is toohot

Bearing undersizedVaries Premature

StarterTransition

1X, 2X ofmotor speed

Gear/motormisalignment

Coupling locked, notlubricated, damaged

Motor incorrectly aligned


16/20

15

Appendix CComponent Damage Assessment

Plain Bearing - Stage______ Part # ____________ Serial # ____________Damaged Area (Describe)

Yes No Yes No

Pads Damaged Profile to Spec.Frosted Minimum Bore to Spec.Excess varnish Shell OD to Spec.Wear/Rub Oil Porting to Spec.Babbitt Flow/Melted Oil Drain to Spec.Scratched Bearing Orientation OK.Severity of Damage None Minor, Reusable Substantial Severe, Destroyed

Number of pads Affected % Area Affected on WorstPad

Thrust Bearing - Stage______ Part # ____________ Serial # ____________Damaged Area (Describe)

Yes No Yes No

Pads Damaged Profile to Spec.Frosted Minimum Bore to Spec.Excess varnish Shell O.D. to Spec.Wear/Rub Oil Porting to Spec.Babbitt Flow/Melted Oil Drain to Spec.Scratched Bearing Orientation OK.Severity of Damage None Minor, Reusable Substantial Severe, Destroyed

Number of pads Affected % Area Affected on WorstPad

Rotor Assembly - Stage______ Part # ____________ Serial # ____________Yes No Yes No

Rotor Bolt Tight To Washer? Nose Washer Tight in

Counterbore?Rotor Bolt Fractured/Bent? Nose-Piece Tight in

Counterbore?Nose Washer fretting/Galling? Galling/Fretting on

Pinion/Impeller Interface?Nose Washer Square inCounterbore?

Other Damage to Nose orWasher?


17/20

16

Active Thrust Bearing - Stage_____ Part # __________ Serial # __________Damaged Area (Describe)

Yes No Yes No

Pads Damaged Babbitt Flow/Melted

Frosted ScratchedExcess varnish Babbitt SeparatedWear/Rub Pocket Dam DamagedSeverity of Damage None Minor, Reusable Substantial Severe, Destroyed

Number of pads affected % Area Affected on WorstPad

Inact ive Thrust Bearing - Stage_____ Part # __________ Serial # _________Damaged Area (Describe)

Yes No Yes No

Pads Damaged Babbitt Flow/MeltedFrosted ScratchedExcess varnish Babbitt SeparatedWear/Rub Pocket Dam DamagedSeverity of Damage None Minor, Reusable Substantial Severe, Destroyed

Number of pads affected % Area Affected on WorstPad

Pinion - Stage______ Part # ____________ Serial # ____________

Area of Damage Type of Damage Severity of DamageGear TeethPlain Bearing Area

Thrust J ournal AreaProbe AreaSeal AreaShaft Bent ?, DescribeQuantify % Tooth Contact

Tooth Contact,Wear

Normal Abnormal, Endloaded

Abnormal, Tip orRoot Loaded

Uniform, Excessive

Bullgear - Part # ______________ Serial # ______________Area of Damage Type of Damage Severity of DamageGear TeethPlain Bearing Area

Thrust J ournal AreaSeal AreaShaft Bent ?, DescribeQuantify % Tooth Contact

Tooth Contact,Wear

Normal Abnormal, Endloaded

Abnormal, Tip orRoot Loaded

Uniform, Excessive


18/20

17

Thrust Bolt - Stage______ Part # _____________ Serial # ______________Yes No Yes No

Tight in Washer? Tight in Counterbore ?

Fractured or Bent? Fretting or Galling at ThrustWasher?

Fretting or Galling at ThrustWasher?

Other Damage To or By ThrustBolt ?

Impeller/Pinion Attachment Stage ________Yes No Severity of Damage ? Lobes/Area Affected ?

Impeller Plugfretting/galling ?Impeller/Pinion facegalling of fretting ?

Pinion Bore Frettingor galling ?Pinion Face frettingor galling ?Pinion thrust endface, fretting or galling?Pinion thrust end plugfretting or galling ?

Thrust collar borefretting or galling ?

Thrust collar facefretting or galling ?

Impeller - Stage______ Part # ______________ Serial # ______________Yes No Severity of Damage etc. Location of Damage, etc.

Blade contact inExducer area?Blades bentor missing ?Blade contact inInducer area?Attachment areadamage?

Foreign objectdamage?Dirt build up?

Thrust collar borefretting or galling?

Thrust collar facefretting or galling?


19/20

18

Diffuser - Stage______ Part # ______________ Serial # ______________Yes No Severity of Damage ? Location of Damage, etc.

Blade contact inExducer area?

Blade contact inInducer area?Diffuser vanes loose orbent?Diffuser vanesmissing?Dirt or other substancebuild up? ?Water carry overevidence?Foreign objectdamage?

Seals - Stage______ Part # ______________ Serial # ______________

Air Yes No Oil Yes No

Rubs? Rubs?

Carbons Float? Carbons Float?

Dirt Build Up? Dirt Build Up?

Other Damage? Other Damage?

Air Coolers - Stage______ Part # ______________ Serial # ______________Yes No Yes No

Water Leaks? Erosion on Water Side?

Excessive Fouling? Erosion, etc. on Air Side?


20/20

Date post:	08-Aug-2018
Category:	Documents
Upload:	rashm006ranjan
View:	232 times
Download:	6 times

Centac Vibration Procedure%2Epdf

Documents