New Tools For Vibration Cm (Presentation)   Rams 2011 Chris Engdahl
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New Tools For Vibration Cm (Presentation) Rams 2011 Chris Engdahl

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Overview of diagnostic functions imbedded in the new Bently Nevada ADAPT wind turbine monitor

Overview of diagnostic functions imbedded in the new Bently Nevada ADAPT wind turbine monitor

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    New Tools For Vibration Cm (Presentation)   Rams 2011 Chris Engdahl New Tools For Vibration Cm (Presentation) Rams 2011 Chris Engdahl Presentation Transcript

    • New Tools for VibrationCondition MonitoringChris EngdahlGE Energy, Measurement & Control Solutions 5th Reliability, Asset Management & Safety (RAMS) Conference 2011
    • Why do PredictiveMaintenance?MaintenancePlanning 2/ GE / July 2, 2012
    • The PdM/PM Advantage : PLANNING Wear Debris - 6 months P1P0 P2 Advanced Vibration diagnostics - 5 months P3 IR Thermography – 3 months P4 Overall Vibration Increase – 10 weeks Better information, P5 Audible noise - 2 weeks better planning F0 Functional Failure P6 Hot to touch 3 days Evaluation/Approval Planning Process Scheduling Process W-? W-6 W-5 W-4 W-3 W-2 W-1 Hard F1 Failure Work Execution Timeline Towards 3/ GE / Failure July 2, 2012
    • New Tools for Vibration ConditionMonitoring Dynamic Energy Index (DEI) Kurtosis Skewness Cumulative Impulse Acceleration Enveloping Sideband Energy Ratio High Pass Filtering 4/ GE / July 2, 2012
    • Dynamic Energy Index (DEI)• Sum energy in discrete bands• Bands correspond to component ranges• Normalize by Torque 5/ GE / July 2, 2012
    • DEI Frequency Bands 0.16 Intermediate Stage High Speed Stage 0.14 Planetary Stage 0.12 Structural Bearing 0.1 Amplitude (g) 0.08 0.06 0.04 0.02 0 1 2 3 4 10 10 10 10 Frequency (Hz) 6/ GE / July 2, 2012
    • Timebase Waveform, Healthy Signal Kurtosis 0.8 0.6 Kurtosis = 3.9 Tail 0.4Variance (standard deviation 0.2squared) involves the 0square of differencesbetween data and the mean -0.2Variance is the 2nd moment -0.4Skew is the 3rd moment Broad -0.6 Center -0.8 0 5 10 15 20 25Kurtosis is the 4th moment. It Time (ms) Timebase Waveform, Failing Generator Bearingputs more emphasis on the 8tails of the distribution 6 Kurtosis = 14 Wide Tail 4Spikier waveforms have 2higher Kurtosis 0Normal vibration 3 -2Sine wave 1.5 Narrow -4 Center -6 -8 7/ 0 5 10 15 20 25 GE / Time (ms) July 2, 2012
    • Skewness CalculationTimebase waveform is treated as a statistical set of dataSkewness = 3rd statistical moment of the set 8/ GE / July 2, 2012
    • Generator Bearings: ESD Noise, HighSkewness WTG128 Generator Outboard Timebase 5/20/2009 2:49:00 PM 1447 rpm; kurt = 9.87; skew = -1.95 5 4 Asymmetric noise, > 5 g (noise can be symmetric!) 3 Kurtosis high Direct high 2 Acceleration (g) 1 0 -1 -2 -3 -4 -5 0 50 100 150 200 250 300 350 Time (ms) This noise happens only on some machines on particular bearing probably associated with grounding brush problems 9/ GE / July 2, 2012
    • Cumulative Impulse• Passage of debris through gear mesh produces a detectable impulse.• Use signal processing to automatically detect, measure, and accumulate a damage index. 10 / GE / July 2, 2012
    • Processing Example Final Maximum For Event (red dot) SlavePlanetaryRotor16Apr10second1; corner = 0.1 Hz; order 2; 13 events for DI = 66 GE CONFIDENTIAL 8 Amplitude 7 Resets Decay Default 6 Envelope Threshold 4g Event 5 Event Adaptive Termination Start Threshold (12 x LP signal) g 4 3 Rectified Signal 2 Low-pass filtered signal (red) 1 0 4.538 4.54 4.542 4.544 4.546 4.548 4.55 4.552 Time (s) 11 / GE / July 2, 2012
    • Acceleration Enveloping Algorithm• High pass filter Exclude mechanical vibration content Include structural resonance frequency range• Rectify• Envelope• FFT 12 / GE / July 2, 2012
    • Impact-Like Structural Event Ringing Defect Repetition Frequency Figure 6. Bearing elements generate a localized impact force and structural resonance response each time the damaged region is engaged. 5 One revolution 4 Amplitude modulation 3 and envelope 2Acceleration (g) 1 0 -1 -2 -3 -4 -5 0 50 100 150 200 250 300 Time (msec) 13 / GE / Defect Repetition = IRBP July 2, 2012
    • Sideband Energy Ratio Healthy Gearmesh Damaged Gearmesh 2X Mesh Amplitude 2X Amplitude 1X 3X Mesh Mesh Mesh 1X 3X Mesh Mesh Frequency Frequency Low (or missing) Higher and/or more Sidebands sidebands S (sideband amplitudes) Sideband Energy Ratio = Center mesh frequency amplitude 14 / GE / July 2, 2012
    • Spectrum Data From Gearbox Test Early In Test Late In Test Little Damage Significant Damage Higher Very Low Sidebands Sidebands 15 / GE / July 2, 2012
    • WTG 130 High Speed Gearbox Lots of stuff! WTG130 High Speed Timebase 4/27/2009 3:23:00 AM 1440 rpm; kurt = 2.99; skew = -0.14 1.5 1 0.5 Acceleration (g) 0 -0.5 -1 -1.5 0 50 100 150 200 250 300 350 Time (ms) 16 / GE / July 2, 2012
    • Where is the noise? WTG130 High Speed Spectrum of Timebase 4/27/2009 3:23:00 AM 1440 rpm 0.18 X: 1247 0.16 X: 503.1 Y: 0.1732 Mesh frequencies obscure the interesting stuff Y: 0.1409 0.14 0.12 1X and 2X HS mesh lines are strong Acceleration (g) 0.1 X: 625 Y: 0.08677 0.08 X: 334.4 0.06 Y: 0.05194 1X, 2X, and 3X IS mesh lines are strong 0.04 X: 168.8 Y: 0.02408 Enveloping 0.02 bandpass region 0 0 2000 4000 6000 8000 10000 12000 14000 Frequency (Hz) 17 / GE / July 2, 2012
    • To filter or not to filter… 1 Kurtosis = 3 WTG130P High Speed Timebase 4/27/2009 3:23:00 AM 1440 rpm; kurt = 2.99; skew = -0.14 0.5 Chaos Acceleration (g)Raw 0 -0.5 -1 0 1 2 3 4 5 6 7 8 Revolutions of HS Shaft 1 Kurtosis = 17 WTG130P High Speed Timebase 4/27/2009 3:23:00 AM 1440 rpm; HP filtered at 5000 Hz; kurt = 16.943 0.5 Clarity5 kHz Amplitude (g) 0HPfilter -0.5 -1 0 1 2 3 4 5 6 7 8 Revolutions of HS Shaft Who would have thought this was hiding in tha 18 / GE / July 2, 2012
    • High-Pass Filtered at 5 kHz Impulses are ringing the gearbox structure WTG130P High Speed Timebase 4/27/2009 3:23:00 AM 1440 rpm; HP filtered at 5000 Hz; kurt = 16.943 1 0.8 0.6 0.4 0.2 Amplitude (g) 0 -0.2 -0.4 -0.6 -0.8 -1 0 1 2 3 4 5 6 7 8 Revolutions of HS Shaft Repeating patterns of 3 impulses modulated at 1X HS rotor spee 19 / GE / July 2, 2012
    • Bently Nevada3701 ADAPTmonitor.Introducing newconditionmonitoringtechnologies…. 20 / GE / July 2, 2012
    • Case History 1:Generator Bearing FaultDetection & Replacement 21 / GE / July 2, 2012
    • Generator Inboard Bearing, WTG 128, BeforeReplacement Timebase Envelope Spectrum WTG128 Inboard Generator Enveloped Spectrum 1/16/2009 1:47:00 PM 1347.641 rpm 1.4 1.2 IRBP Frequency 1 Acceleration (g) 0.8 0.6 0.4 0.2 IRBP Fault 0 0 5 10 15 20 25 30 35 40 45 50 Frequency (Orders of HSS) 22 / GE / July 2, 2012
    • Generator Inboard Bearing, WTG 128, AfterReplacement Timebase Envelope Spectrum WTG128 Generator Inboard Envelope Spectrum 4/27/2009 8:51:00 AM 1426 rpm 1.4 1.2 1 Acceleration (g) 0.8 0.6 0.4 0.2 0 0 5 10 15 20 25 30 35 40 45 50 Frequency (Orders of Main Shaft)) 23 / GE / July 2, 2012
    • Case History 2:Cracked Race 24 / GE / July 2, 2012
    • 1.5 MW Wind Turbine Gearbox And Sensor High-Speed Output Shaft (HSS) 2 stage gearbox Downwind Bearing Planetary + Parallel HSS Accelerometer 25 / GE / July 2, 2012
    • Repeating Initial Detection Impulses HSS accel timebase waveform Near full speed September 2008 ~5 g peakRepeating sequences of impulses Single Impulse 1 RevolutionEach sequence is one defect encounteringmultiple rolling elements in load zoneImpulses are separated by element passagefrequency 26 / GE / July 2, 2012
    • Initial Detection, Envelope Spectrum IRBP 1X HSS Split Lines 10.8 XStrong 1X modulation 1X + harmonics 1X sidebands on IRBP2 overlapping series 1X + harmonics IRBP +/– 1X, 2X, … Difference visible at split lines 1X Sidebands 27 / GE / July 2, 2012
    • Double High-Low-High ImpulseApril 2010Same MachineDouble impulse indicates newdamage. Not separated by IRBP.New damage is smaller thanolder damage. 1X Line Higher 1 Revolution IRBP Line LowerHigh-low-high pattern suggestsmultiple faults.1X line higher because of denserpattern of impulses.Average bearing fault impulseslower, so IRBP line lower. 28 / GE / July 2, 2012
    • Trend Data, August Through April Direct Direct changes little IRBP IRBP decreases Kurtosis Kurtosis decreases 29 / GE / July 2, 2012
    • Inspection And CrackCrack does not extendacross raceThis was largest of 4 Rolling Elementcracks found Inner Race Surface 30 / GE / July 2, 2012
    • Diagnostic SequenceA clear IRBP bearing defect frequency found in the envelope spectrumVery narrow impulse/response signatures in the timebase waveform suggested a narrow defectClear 1X modulation of the impulse amplitude, consistent with inner race faultSecond turbine with similar symptoms suggesting multiple faults, inspected, and cracks found 31 / GE / July 2, 2012
    • Questions? 32 / GE / July 2, 2012