monitoring gear boxes with peakvue - niagara frontier chapter home

1

Monitoring Gear Boxes with PeakVue

Presentation at Niagara Falls Vibration Institute Chapter

January 20, 2005

2

WHAT IS A STRESS WAVE?WHAT IS A STRESS WAVE?

3

HertzHertz TheoryTheory Prediction for Various Size Prediction for Various Size Metal BallsMetal Balls

4

Frequencies Excited by 0.5”, 1.0”. And 1.5” D Balls Impacting

RM

S A

ccel

erat

ion

in G

-s

Frequency in kHz

CENT - OFF ROUTE EQUIPMENTOFF ROUTE - (25-Feb-99)

0 10 20 30 40 50 60 70 80

Max Amp .84

Plot Scale

0

0.9

14:52:1325-Feb-99

14:54:0225-Feb-99

14:54:5225-Feb-99

1.5" D Ball

1.0" D Ball

0.5" D Ball

5

Impacting and Friction: 1.0 +” D Roller

CENT - OFF ROUTE EQUIPMENTOFF ROUTE -

Label: OFFROUTE-A-1 /

Analyze Spectrum 28-Feb-01 15:07:31

RMS = .0892 LOAD = 100.0 RPM = 696. (11.60 Hz)

0 10000 20000 30000 40000

0

0.004

0.008

0.012

0.016

0.020

0.024

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

6

• Capture with accelerometer• High-pass filter• Capture time block of data

(peak values)a) Spectral Analysisb) Autocorrelation analysis

Analysis of Stress WavesAnalysis of Stress Waves

7

Example Time Waveform

Select Fmax

Delta t = 1/(2.56 × Fmax)

Sequentially insert in each Delta t the Peak Value observed over that time increment

8

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

9

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

10

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

11

( ) ( ) ( ) ( )

2,1;

,1;

01 2/

1

Njtj

Nitit

txtxA

A

j

i

N

ijiij

=∆=

=∆=

∑ +==

τ

ττ

Computation of Autocorrelation

12

FHP ≥ Fmax

• Select Fmax Based on Fault FrequenciesBearings: Fmax > 4 × BPFIGearing: Fmax > 2 × GMF

• Select Resolution (# Lines) Based on Lowest Fault FrequencyBearings: CageGearing: Slowest shaft for gear pair in Mesh

Measurement Setup Parameters

Measurement Setup Parameters

13

• Cage - requires 12+ shaft revs

Measurement Setup Parameters (cont.)

Measurement Setup Parameters (cont.)

ordersinline#

Revs#mF

s=

• Shaft - Requires 5+ shaft revs• FHP (High-Pass Filter)

– Same (highest) over a machine (structure with continuous housing).

– FHP greatest for bearings or gears on machine– Fmax can be varied, but same FHP must be used

on all points on component (i.e., throughout Gearbox)

14

Guidelines for setting Pk-Pk PeakVue Time Waveform

Alert Alarm Levels for an inner race fault

(Set Fault Alarm = 2 X Alert Alarm)

Guidelines for setting Pk-Pk PeakVue Time Waveform

Alert Alarm Levels for an inner race fault

(Set Fault Alarm = 2 X Alert Alarm)

3 900

RPM 0.75

×

=g's for RPM < 900

g’s = 3 , for 900 < RPM ≤ 4000 ,

3 4000RPM 0.5

×

=g's for 4000 < RPM ≤ 10000 ,

g’s = 5 , for RPM > 10000 ,

Recom m ended P-P Tim e Waveform Aler t Lim its

0.577

4.743

3.000 3.000

0.1030.100

1.000

10.000

1 10 100 1000 10000

Speed (RPM)

Acc

eler

atio

n in

g's

(p-p

)

15

Gear Box

• Case Study # 1– A) Cracked Tooth on post rebuild gear

box– B) Cracked Tooth on Precision Tension

Bridle

17

Fault under Meas Point G5

19

Cracked Tooth Highlighted

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

21

Plan view of precision tension bridle gearbox (single speed reduction with

two output shafts)

22

WAVEFORM DISPLAY 14-Apr-97 07:59:17 RMS = .3687 PK(+) = 1.59 PK(-) = 1.86 CRESTF= 5.06

0 50 100 150 200-2.5

-2.0

-1.5

-1.0

-0.5

0

0.5

1.0

1.52.0

Time in mSecs

Acc

eler

atio

n in

G-s

SM - Precision Tension BridlePT BRIDLE -GV3

ROUTE SPECTRUM 14-Apr-97 07:59:17 OVERALL= .0812 V-DG PK = .0808 LOAD = 100.0 RPM = 526. RPS = 8.77

0 500 1000 1500 20000

0.01

0.02

0.03

0.04

Frequency in Hz

PK

Vel

ocity

in In

/Sec

201.

59

350.

68

Freq: Ordr: Spec:

351.25 40.07 .02589

GM 2

GM 1

Velocity spectral and acceleration waveform data (Fmax=2000 Hz) from the bearing on the

input shaft of the precision tension bridle gearbox

23

WAVEFORM DISPLAY 14-Apr-97 08:28:16 RMS = 7.16 PK(+) = 36.54 PK(-) = 4.82 CRESTF= 5.10

0 0.5 1.0 1.5 2.0-10

0

10

20

30

40

Time in Seconds

Acc

eler

atio

n in

G-s

SM - Precision Tension BridlePT BRIDLE -GV3

ANALYZE SPECTRUM 14-Apr-97 08:28:16 (Filtr- HP 500 Hz) RMS = 6.50 LOAD = 100.0 RPM = 216. RPS = 3.60

0 50 100 150 2000

1

2

3

4

5

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

Freq: Ordr: Spec:

3.625 1.008 3.288

PeakVue

PeakVue spectral and waveform data (Fmax=200 Hz) from the bearing on the input shaft of the precision tension bridle gearbox

24

GM2

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

25

Gearbox• Case Study # 2

– Eccentric gear on post rebuild gear box

28

Defective Gear Placed in Separate Gear Box

29

Gear Box

• Case study #3– Worn spline on post rebuild gear box

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

34

4.13 g’s

1X GMF

2X GMF

Velocity

BPFO

Velocity spectral and acceleration waveform data (Fmax=800 Hz) from the bearing on the input shaft of the

gearbox (Sept 15)

35

BPFO = 64.38 Hz = 10.75 X RPM

1/BPFO

36.96 g

PeakVue

Peakvue spectral and waveform data (Fmax=1000 Hz) from the bearing on the

input shaft of the gearbox (Sept 15)

36

PeakVue Before Bearing Replacement

PeakVue After Bearing Replacement

BPFO

Peakvue spectral and waveform data (Fmax=1000 Hz) from the bearing on the input shaft of the gearbox before and after

bearing replacement

37

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

38

Bearing Outer Race

• Case Study #5 BPFO– Early stage fatiguing – Shaft speed=650 RPM– Alert=4.7 g’s

39

Routine Waveform 03-Feb-03 09:04:17 (PkVue-HP 2000 Hz) RMS = .2671 PK(+) = 1.15 CRESTF= 4.32

0 3 6 9 12 15 18

0

0.2

0.4

0.6

0.8

1.0

1.2

1.4

Revolution Number

Acc

eler

atio

n in

G-s

WDT - GBOXGBOX -P4 Measurement Pt4

Routine Spectrum 03-Feb-03 09:04:17 (PkVue-HP 2000 Hz) RMS = .1353 LOAD = 100.0 RPM = 538. (8.97 Hz)

0 10 20 30 40 50

0

0.01

0.02

0.03

0.04

0.05

0.06

0.07

Frequency in Orders

RM

S A

ccel

erat

ion

in G

-s

Ordr: Freq: Spec:

5.253 47.12 .06017

>skf nj2332EC C=BPFO

C C C C C C C C

Alert=4.7

g’s

Alert=4.7 g’s

40

WDT - GBOXGBOX -P4 Measurement Pt4

Revolution Number

Acc

eler

atio

n in

G-s

0 3 6 9 12 15 18

1.15 .0892 03-Feb-03 09:04

.93 .0959 02-Feb-03 15:17

.92 .0899 02-Feb-03 16:22

.33 .0963 02-Feb-03 18:30

Impacting Sporadic

41

Bearing (Inner Race)

• Case Study #6– BPFI on bearing on output shaft– Severity ascertained from trending

42

BPFI with 1X RPM sidebands

2X BPFI1X RPM

Trend (2 years) of the maximum peak amplitude (g’s) from the Peakvue

waveform and a Peakvue spectrum on May 25

43

No indication of a bearing fault

2X GMFVelocity

GMF

Trend (2 years) of the bearing frequency band from the velocity spectrum and a

Velocity spectrum on May 25

44

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

Peakvue trends

45

RFPD - HOT MILL-F5 PINION STAND 200HMF5PINSTD-P4H BOT BRG OUTPUT SIDE HORIZ.PK-VUE

Label: Trend After Bearing Replaced

Trend Display of OVERALL VALUE

-- Baseline -- Value: .04003 Date: 01/07/99

0 100 200 300 400 500 600 700 800

0

0.1

0.2

0.3

0.4

0.5

0.6

Days: 07/31/98 To 08/17/00

RM

S A

ccel

erat

ion

in G

-s

11/0

6/98

03/2

5/99

10/1

9/99

02/0

1/00

05/1

8/00

08/1

7/00

06/2

8/00

Date: Time: Ampl:

08/17/00 13:03:27 .01550

PeakVue Trend Before & After Bearing was ReplacedPeakVue Trend Before & After Bearing was Replaced(Trend of Digital Overall)(Trend of Digital Overall)

46

Bearing Inner Race• Case Study # 7

– BPFI (mechanical plus lubrication)

48

Route Waveform 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz) RMS = .8999 PK(+) = 3.58 CRESTF= 3.94

0 200 400 600 800 1000

0

0.5

1.0

1.5

2.0

2.5

3.0

3.54.0

Time in mSecs

Acc

eler

atio

n in

G-s

IGB - Roller Mill Peak VueRM-PV -G2 Gearbox Point 2

Route Spectrum 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz) OVERALL= .4408 A-DG RMS = .4387 LOAD = 100.0 RPM = 892. (14.87 Hz)

0 50 100 150 200 250 300 350 400

0

0.03

0.06

0.09

0.12

0.15

0.18

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

14.8

7

129.

49

258.

98

388.

47

Freq: Ordr: Spec: Dfrq:

114.63 7.709 .09612 14.86

BPFI

Data acquired outer bearing re input

49


Route ACorr(Wf) 09-Jan-02 12:43:10 (PkVue-HP 1000 Hz)

RMS = .0860 LOAD = 100.0 RPM = 892. (14.87 Hz)

PK(+) = .4534 PK(-) = .1173 CRESTF= 5.27

0 100 200 300 400 500 600

-1.0

-0.5

0

0.5

1.0

Time in mSecs

Cor

rela

tion

Fact

or

Typical BPFI pattern in Autocorrelation

50

Trended Peak g-level from G2Peak g Trend Data For Measurement Point G2

0

10

20

30

40

50

60

70

80

90

0 50 100 150 200 250 300 350

Days

g's

Pea

k

Peak G's

Alert

Fault

51

Route Waveform 06-Feb-02 12:43:59 (PkVue-HP 1000 Hz) RMS = 12.87 PK(+) = 51.09 CRESTF= 3.92

0 200 400 600 800 1000

0

10

20

30

40

50

60

Time in mSecs

Acc

eler

atio

n in

G-s


Route Spectrum 06-Feb-02 12:43:59 (PkVue-HP 1000 Hz) OVERALL= 8.28 A-DG RMS = 8.28 LOAD = 100.0 RPM = 893. (14.89 Hz)

0 50 100 150 200 250 300 350 400

0

1

2

3

4

5

6

7

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

14.8

9

129.

67

259.

35

389.

02


114.78 7.709 1.034 14.89

BPFI

51 g’s on Point G2 on February 6, 2002

52

Route Waveform 06-Feb-02 12:43:19 (PkVue-HP 1000 Hz) RMS = 6.71 PK(+) = 24.21 CRESTF= 3.62

0 200 400 600 800 1000

0

4

8

12

16

20

24

Time in mSecs

Acc

eler

atio

n in

G-s


Route Spectrum 06-Feb-02 12:43:19 (PkVue-HP 1000 Hz) OVERALL= 3.76 A-DG RMS = 3.74 LOAD = 100.0 RPM = 893. (14.89 Hz)

0 50 100 150 200 250 300 350 400

0

0.4

0.8

1.2

1.6

2.0

2.4

2.83.2

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

14.8

9

129.

68

259.

36

389.

05


114.80 7.709 .475 14.88

25 g’s on Point G1 on February 6, 2002.

53

Note metal removal on inner race downstream of fault

54

Gear Fault in Planetary Gear

• Planetary Gearbox

• Carrier turning at approximately 20 RPM

55

Routine Waveform 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz) RMS = .1352 PK(+) = .3424 CRESTF= 2.53 DCoff = .2176

0 4 8 12 16 20 24 28 32

0

0.08

0.16

0.24

0.32

0.40

Time in Seconds

Acc

eler

atio

n in

G-s

WDT - GBOXGBOX -P2A Measurement Pt2A

Routine Spectrum 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz) RMS = .0401 LOAD = 100.0 RPM = 20. (.33 Hz)

0 10 20 30 40 50

0

0.005

0.010

0.015

0.020

Frequency in Hz

RM

S A

ccel

erat

ion

in G

-s

Freq: Ordr: Spec:

1.000 3.006 .01473

Dominant activity at 3x: 0.34 g’s on Dominant activity at 3x: 0.34 g’s on October 23, 2002October 23, 2002

56


Routine ACorr(Wf) 23-Oct-02 13:16:58 (PkVue-HP 2000 Hz)

RMS = .1256 LOAD = 100.0 RPM = 20. (.33 Hz)

PK(+) = .5790 PK(-) = .2883 CRESTF= 4.61

0 4 8 12 16

-1.0

-0.5

0

0.5

1.0

Time in Seconds

Cor

rela

tion

Fact

orAutocorrelation on October 23, 2002

57

Routine Waveform 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS = .2261 PK(+) = 2.10 CRESTF= 9.27 DCoff = .2427

0 10 20 30 40 50 60 70 80

0

0.4

0.8

1.2

1.6

2.0

2.4

Time in Seconds

Acc

eler

atio

n in

G-s


Routine Spectrum 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS = .1177 LOAD = 100.0 RPM = 20. (.33 Hz)

0 4 8 12 16

0

0.01

0.02

0.03

0.04

0.05

0.060.07

Frequency in Orders

RM

S A

ccel

erat

ion

in G

-s

Ordr: Freq: Spec:

1.010 .338 .04590

Dominate activity at 1x: 2.1 g’s on December 30, 2002

58


Routine ACorr(Wf) 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz)

RMS = .1682 LOAD = 100.0 RPM = 20. (.33 Hz)

PK(+) = .8097 PK(-) = .2306 CRESTF= 4.81

0 5 10 15 20 25 30 35 40

-1.0

-0.5

0

0.5

1.0

Time in Seconds

Cor

rela

tion

Fact

or

Time: Ampl: Dtim: Freq:

16.94 .220 1.209 .827

Dela orders=2.472

Autocorrelation on December 30, 2002

Dominate activity at 2.47 orders

59

Routine Waveform 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS = .2261 PK(+) = 2.10 CRESTF= 9.27 DCoff = .2427

0 10 20 30 40 50 60 70 80

0

0.4

0.8

1.2

1.6

2.0

2.4

Time in Seconds

Acc

eler

atio

n in

G-s


Routine Spectrum 30-Dec-02 12:46:34 (PkVue-HP 2000 Hz) RMS = .1177 LOAD = 100.0 RPM = 20. (.33 Hz)

0 4 8 12 16

0

0.01

0.02

0.03

0.04

0.05

0.060.07

Frequency in Orders

RM

S A

ccel

erat

ion

in G

-s

Ordr: Freq: Spec:

2.472 .826 .04985

89/36=2.472

Activity Highlighted at 2.47 Orders

60

2.47 activity gone on February 3, 2003

Routine Waveform 02-Feb-03 15:16:20 (PkVue-HP 2000 Hz) RMS = .3252 PK(+) = .7509 CRESTF= 2.31

0 3 6 9 12 15 18 21 24 27

0.2

0.3

0.4

0.5

0.6

0.7

0.8

Revolution Number

Acc

eler

atio

n in

G-s


Routine Spectrum 02-Feb-03 15:16:20 (PkVue-HP 2000 Hz) RMS = .0312 LOAD = 100.0 RPM = 20. (.33 Hz)

0 5 10 15 20 25 30

0

0.004

0.008

0.012

0.016

Frequency in Orders

RM

S A

ccel

erat

ion

in G

-s

2.47

3.00

6.00

9.00

12.0

0

15.0

0

18.0

0

21.0

0

24.0

0

27.0

0

Ordr: Freq: Spec:

2.471 .825 .00484

Dominate activity at 3x: 0.75 g’s

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