Presentation at Niagara Falls Vibration Institute Chapter January 20, 2005

Transcription

1 Monitoring Gear Boxes with PeakVue Presentation at Niagara Falls Vibration Institute Chapter January 20,

2 WHAT IS A STRESS WAVE? 2

3 Hertz Theory Prediction for Various Size Metal Balls 3

4 Frequencies Excited by 0.5, 1.0. And 1.5 D Balls Impacting CENT - OFF ROUTE EQUIPMENT OFF ROUTE - (25-Feb-99) Max Amp.84 Plot Scale " D Ball 25-Feb-99 14:54:52 RMS Acceleration in G-s 1.0" D Ball 25-Feb-99 14:54: " D Ball 25-Feb-99 14:52: Frequency in khz 4

5 Impacting and Friction: D Roller CENT - OFF ROUTE EQUIPMENT OFF ROUTE - Analyze Spectrum 28-Feb-01 15:07:31 RMS =.0892 LOAD = RPM = 696. (11.60 Hz) RMS Acceleration in G-s Frequency in Hz Label: OFFROUTE-A-1 / 5

6 Analysis of Stress Waves Capture with accelerometer High-pass filter Capture time block of data (peak values) a) Spectral Analysis b) Autocorrelation analysis 6

7 Example Time Waveform Select F max Delta t = 1/(2.56 F max ) Sequentially insert in each Delta t the Peak Value observed over that time increment 7

8 PeakVue Waveform Indicates Defective Rolling Elements (Rollers pass in and out of load zone at rate of Cage Freq.) 8

9 PeakVue Spectrum Derived from PeakVue Waveform (Cage Freq. = 3.43 Hz; BSF = 40.6 Hz) 9

10 Autocorrelation Coefficient Function Identifies Dominant Impact Sources in PeakVue Data 10

11 11 ( ) ( ) ( ) ( ) 2 1, ; 1, ; / 1 N j t j N i t i t t x t x A A j i N i j i i j = = = = + = = τ τ τ Computation of Autocorrelation

12 Measurement Setup Parameters F HP F max Select F max Based on Fault Frequencies Bearings: F max > 4 BPFI Gearing: F max > 2 GMF Select Resolution (# Lines) Based on Lowest Fault Frequency Bearings: Cage Gearing: Slowest shaft for gear pair in Mesh 12

13 Measurement Setup Parameters (cont.) Cage - requires 12+ shaft revs # Revs = F m # lines in orders Shaft - Requires 5+ shaft revs F HP (High-Pass Filter) Same (highest) over a machine (structure with continuous housing). F HP greatest for bearings or gears on machine F max can be varied, but same F HP must be used on all points on component (i.e., throughout Gearbox) 13

14 Guidelines for setting Pk-Pk PeakVue Time Waveform Alert Alarm Levels for an inner race fault (Set Fault Alarm = 2 X Alert Alarm) Acceleration in g's (p-p) Recommended P-P Time Waveform Alert Limits Speed (RPM) RPM 0.75 g's = for RPM < 900 g s = 3, for 900 < RPM 4000, RPM 0.5 g's = for 4000 < RPM 10000, g s = 5, for RPM > 10000, 14

15 Gear Box Case Study # 1 A) Cracked Tooth on post rebuild gear box B) Cracked Tooth on Precision Tension Bridle 15

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17 Fault under Meas Point G5 17

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19 Cracked Tooth Highlighted 19

20 Cracked Teeth in Precision Tension Bridle GearBox - Based on Pk-Pk Level of 41 g s in TWF - Pronounced Impact Pulses in TWF (2/Rev) - No Real Indication of Problem in Vibration Data 20

21 Plan view of precision tension bridle gearbox (single speed reduction with two output shafts) 21

22 Velocity spectral and acceleration waveform data (Fmax=2000 Hz) from the bearing on the input shaft of the precision tension bridle SM - Precision Tension Bridle PT BRIDLE -GV GM 1 gearbox PK Velocity in In/Sec GM ROUTE SPECTRUM 14-Apr-97 07:59:17 OVERALL=.0812 V-DG PK =.0808 LOAD = RPM = 526. RPS = 8.77 Acceleration in G-s Frequency in Hz Time in msecs WAVEFORM DISPLAY 14-Apr-97 07:59:17 RMS =.3687 PK(+) = 1.59 PK(-) = 1.86 CRESTF= 5.06 Freq: Ordr: Spec:

23 SM - Precision Tension Bridle PT BRIDLE -GV3 5 ANALYZE SPECTRUM 14-Apr-97 08:28:16 shaft 4 of the precision tension bridle PeakVue gearbox (Filtr- HP 500 Hz) RMS = 6.50 LOAD = RPM = 216. RPS = 3.60 RMS Acceleration in G-s PeakVue spectral and waveform data (F max =200 Hz) from the bearing on the input 2 1 Acceleration in G-s Frequency in Hz WAVEFORM DISPLAY 14-Apr-97 08:28:16 RMS = 7.16 PK(+) = PK(-) = 4.82 CRESTF= Time in Seconds Freq: Ordr: Spec:

24 PeakVue spectral and (Fmax=100 Hz but with a 5000 Hz HP filter) from the bearing on the input shaft of the precision tension bridle gearbox GM 2 24

25 Case Study # 2 Gearbox Eccentric gear on post rebuild gear box 25

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28 Defective Gear Placed in Separate Gear Box 28

29 Gear Box Case study #3 Worn spline on post rebuild gear box 29

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33 Bearing-Outer Race Case Study #4 BPFO in Pinion Stand Gearbox Speed of shaft=360 RPM Peak g-level=37 g s Fault=6.3 g s 33

34 Velocity spectral and acceleration waveform data (Fmax=800 Hz) from the bearing on the input shaft of the gearbox (Sept 15) 1X GMF Velocity BPFO 2X GMF 4.13 g s 34

35 Peakvue spectral and waveform data (Fmax=1000 Hz) from the bearing on the input shaft of the gearbox (Sept 15) BPFO = Hz = X RPM PeakVue 1/BPFO g 35

36 Peakvue spectral and waveform data (Fmax=1000 Hz) from the bearing on the input shaft of the gearbox before and after bearing replacement BPFO PeakVue Before Bearing Replacement PeakVue After Bearing Replacement 36

37 Closeup picture of the outer race of the defective bearing showing significant spalling over an area of 5 in. x 5 in. 37

38 Bearing Outer Race Case Study #5 BPFO Early stage fatiguing Shaft speed=650 RPM Alert=4.7 g s 38

39 A l e r t = 4. 7 RMS Acceleration in G-s g s Acceleration in G-s Alert=4.7 g s WDT - GBOX GBOX -P4 Measurement Pt4 C C C C C C C C Frequency in Orders Routine Spectrum 03-Feb-03 09:04:17 (PkVue-HP 2000 Hz) RMS =.1353 LOAD = RPM = 538. (8.97 Hz) >skf nj2332ec C=BPFO Routine Waveform 03-Feb-03 09:04:17 (PkVue-HP 2000 Hz) RMS =.2671 PK(+) = 1.15 CRESTF= Revolution Number Ordr: Freq: Spec:

40 Impacting Sporadic WDT - GBOX GBOX -P4 Measurement Pt Feb-03 18:30 Acceleration in G-s Feb-03 16:22 02-Feb-03 15: Feb-03 09: Revolution Number 40

41 Bearing (Inner Race) Case Study #6 BPFI on bearing on output shaft Severity ascertained from trending 41

42 Trend (2 years) of the maximum peak amplitude (g s) from the Peakvue waveform and a Peakvue spectrum on May 25 BPFI with 1X RPM sidebands 1X RPM 2X BPFI 42

43 Trend (2 years) of the bearing frequency band from the velocity spectrum and a Velocity spectrum on May 25 2X GMF Velocity GMF No indication of a bearing fault 43

44 Picture of the defective bearing with a significant inner race defect identified by Peakvue trends 44

45 PeakVue Trend Before & After Bearing was Replaced (Trend of Digital Overall) RMS Acceleration in G-s RFPD - HOT MILL-F5 PINION STAND 200 HMF5PINSTD-P4H BOT BRG OUTPUT SIDE HORIZ.PK-VUE 10/19/99 02/01/00 05/18/00 06/28/00 Trend Display of OVERALL VALUE -- Baseline -- Value: Date: 01/07/ /06/98 03/25/99 08/17/ Days: 07/31/98 To 08/17/00 Label: Trend After Bearing Replaced Date: Time: Ampl: 08/17/00 13:03:

46 Bearing Inner Race Case Study # 7 BPFI (mechanical plus lubrication) 46

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48 Data acquired outer bearing re input RMS Acceleration in G-s IGB - Roller Mill Peak Vue RM-PV -G2 Gearbox Point BPFI Route Spectrum 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz) OVERALL=.4408 A-DG RMS =.4387 LOAD = RPM = 892. (14.87 Hz) 0 Acceleration in G-s Frequency in Hz Route Waveform 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz) RMS =.8999 PK(+) = 3.58 CRESTF= Time in msecs Freq: Ordr: Spec: Dfrq:

49 Typical BPFI pattern in Autocorrelation IGB - Roller Mill Peak Vue RM-PV -G2 Gearbox Point 2 Route ACorr(Wf) 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz) RMS =.0860 LOAD = RPM = 892. (14.87 Hz) PK(+) =.4534 PK(-) =.1173 CRESTF= 5.27 Correlation Factor Time in msecs 49

50 Trended Peak g-level from G2 Peak g Trend Data For Measurement Point G g's Peak Peak G's Alert Fault Days 50

51 51 g s on Point G2 on February 6, 2002 RMS Acceleration in G-s IGB - Roller Mill Peak Vue RM-PV -G2 Gearbox Point BPFI Route Spectrum 06-Feb-02 12:43:59 (PkVue-HP 1000 Hz) OVERALL= 8.28 A-DG RMS = 8.28 LOAD = RPM = 893. (14.89 Hz) 0 Acceleration in G-s Frequency in Hz Route Waveform 06-Feb-02 12:43:59 (PkVue-HP 1000 Hz) RMS = PK(+) = CRESTF= Time in msecs Freq: Ordr: Spec: Dfrq:

52 25 g s on Point G1 on February 6, RMS Acceleration in G-s IGB - Roller Mill Peak Vue RM-PV -G1 Gearbox Point Route Spectrum 06-Feb-02 12:43:19 (PkVue-HP 1000 Hz) OVERALL= 3.76 A-DG RMS = 3.74 LOAD = RPM = 893. (14.89 Hz) 0 Acceleration in G-s Frequency in Hz Route Waveform 06-Feb-02 12:43:19 (PkVue-HP 1000 Hz) RMS = 6.71 PK(+) = CRESTF= Time in msecs Freq: Ordr: Spec: Dfrq:

53 Note metal removal on inner race downstream of fault 53

54 Gear Fault in Planetary Gear Planetary Gearbox Carrier turning at approximately 20 RPM 54

55 Dominant activity at 3x: 0.34 g s on October 23, 2002 RMS Acceleration in G-s GBOX WDT - GBOX -P2A Measurement Pt2A Routine Spectrum 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz) RMS =.0401 LOAD = RPM = 20. (.33 Hz) 0 Acceleration in G-s Frequency in Hz Routine Waveform 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz) RMS =.1352 PK(+) =.3424 CRESTF= 2.53 DCoff = Time in Seconds Freq: Ordr: Spec:

56 Autocorrelation on October 23, GBOX WDT - GBOX -P2A Measurement Pt2A Routine ACorr(Wf) 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz) 0.5 RMS =.1256 LOAD = RPM = 20. (.33 Hz) Correlation Factor 0 PK(+) =.5790 PK(-) =.2883 CRESTF= Time in Seconds 56

57 Dominate activity at 1x: 2.1 g s on December 30, 2002 RMS Acceleration in G-s GBOX WDT - GBOX -P2A Measurement Pt2A Routine Spectrum 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS =.1177 LOAD = RPM = 20. (.33 Hz) 0 Acceleration in G-s Frequency in Orders Routine Waveform 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS =.2261 PK(+) = 2.10 CRESTF= 9.27 DCoff = Time in Seconds Ordr: Freq:.338 Spec:

58 Autocorrelation on December 30, Dominate activity at 2.47 orders WDT - GBOX GBOX -P2A Measurement Pt2A Dela orders=2.472 Routine ACorr(Wf) 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS =.1682 LOAD = RPM = 20. (.33 Hz) Correlation Factor 0 PK(+) =.8097 PK(-) =.2306 CRESTF= Time in Seconds Time: Ampl: Dtim: Freq:

59 Activity Highlighted at 2.47 Orders RMS Acceleration in G-s WDT - GBOX GBOX -P2A Measurement Pt2A 89/36=2.472 Routine Spectrum 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS =.1177 LOAD = RPM = 20. (.33 Hz) 0 Acceleration in G-s Frequency in Orders Routine Waveform 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS =.2261 PK(+) = 2.10 CRESTF= 9.27 DCoff = Time in Seconds Ordr: Freq:.826 Spec:

60 2.47 activity gone on February Dominate activity at 3x: 0.75 g s 3, 2003 RMS Acceleration in G-s GBOX WDT - GBOX -P2A Measurement Pt2A Routine Spectrum 02-Feb-03 15:16:20 (PkVue-HP 2000 Hz) RMS =.0312 LOAD = RPM = 20. (.33 Hz) Acceleration in G-s Frequency in Orders Routine Waveform 02-Feb-03 15:16:20 (PkVue-HP 2000 Hz) RMS =.3252 PK(+) =.7509 CRESTF= Revolution Number Ordr: Freq: Spec: