Download - 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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
5/20
4
Table 3.
During disassembly of the compressor
Responsibility Action Comments/Suggestions
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
6/20
5
Table 3.
Problem Evaluation
Responsibility Action Comments/Suggestions
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
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.
AftermarketCustomerService Engineer
Assure that the problem hasbeen resolved.
-
8/22/2019 Centac Vibration Procedure%2Epdf
8/20
7
Table 3.
Solution Follow-up
Responsibility Action Comments/SuggestionsServiceTechnicianSupervisor
Release service technician fromsite when customer agrees thatthe initial problem has beenresolved.
AftermarketCustomerService Engineer
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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)
-
8/22/2019 Centac Vibration Procedure%2Epdf
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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
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.
-
8/22/2019 Centac Vibration Procedure%2Epdf
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
Spectra test,unloaded, loaded,at surge, andduring coast-down
-
8/22/2019 Centac Vibration Procedure%2Epdf
15/20
14
Randomfrequencies,or 1X
Gear MeshErrors
Damaged or worn piniontooth
Damaged or worn bullgeartooth
Casingaccelerometermeasurements
Spectra test,unloaded, loaded,at surge, andduring coast-down
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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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?
-
8/22/2019 Centac Vibration Procedure%2Epdf
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
-
8/22/2019 Centac Vibration Procedure%2Epdf
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?
-
8/22/2019 Centac Vibration Procedure%2Epdf
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?
-
8/22/2019 Centac Vibration Procedure%2Epdf
20/20