mike cannon automated bearing dli engineering wear … auto bearing fault.pdf · 2016-08-04 · d l...

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Automated BearingWear Detection

Mike Cannon

DLI Engineering

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Vibration: an indicator of machine condition

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Vibration Contents by Frequency

FFT Spectral Analysis

Identify Peaks & Patterns -

Relationship to

machinery components

Amplitude of peak – comparison tobaseline

Diagnosis and severity of machine problem

Repair recommendations –

Specific to problem

Priority and Remaining life

Narrow band Vibration Analysis

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Time Domain & Frequency Domain

Vibration Wave Form

F r e q u e n c yA m p l i t u d e v s . t i m e

V i b r a t i o n S p e c t r u m

A complex signal is the sum of several sine waves

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Vibration SignalVibration Signal

Vibration Data Acquisition & ProcessingAnalog SignalAnalog Signal

is Digitizedis Digitized

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Forcing Frequencies Rotation Rate of Fan

Five-Blades on Fan

Fly swatter against the blades

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Forcing Frequencies in Spectra

0 1 2 3 4 5 6 7 8 9 10

10 Orders

IPS

1X RPMFly Swatter

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Results = Problems Identified

Imbalance Misalignment Bearings (BAD /COCKED)

Bent shaft Looseness

Out-of-round Journal Gear Problems Impeller Blade Problems Magnetic Noise Electrical Noise

Motor

GearCprsr

Detection

Diagnosis &

Prognosis

of specific problems

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Accurate results from quality data

Triaxial Sensor

All 3 axes - more complete analysis

Improves accuracy of diagnosis

Permanently Mounted Stud

Excellent frequency response

Repeatability = accurate trending

Barcoding

Faster and more accurate

Prevents human error

100 100

WATCHMAN TEST POINT

DO NOT PAINT

100 100

WATCHMAN TEST POINT

DO NOT PAINT

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Baseline Data to define the healthy machine

800 Alarm Levels

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Order Normalization

Conventional Vibration Spectrum1800 rpm component

140

130

120

100

90

80

70

60

110-

0 3 6 9 12 15 18

Frequency 0-18,000 RPM

Am

plitu

deV

dB

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Order Normalization

Order Normalized Vibration Spectrum

0 1 2 3 4 5 6 7 8 9 10

140

130

120

110-

100

90

80

70

60

Frequency in Orders (multiples of rotation rate)

Am

plitu

dein

VdB

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Results from Vibration Analysis

Level IReports

Level IReports

Level IITrends

Level IITrends

Level IIISignatures

Level IIISignatures

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1. MANDATORY Repair Recommendations

AIR CONDITIONING SALTWATER CIRCULATING PUMP #3Mandatory: Overhaul unit.

AUXILIARY MACHINERY COOLING WATER PUMP #2BMandatory: Align Motor and Pump.

2. IMPORTANT Repair Recommendations

MAIN CONDENSATE PUMP (MD) #1AImportant: Replace motor bearings.Desirable: Monitor pump bearings for increased vibration.

LUBE OIL SERVICE PUMP (ATTACHED) #1CImportant: Inspect bevel gears for proper meshing; ifsatisfactory, check intermediate shaft bearings for looseness.

TURBO-GENERATOR (60HZ) #8Important: Inspect accessory drive shaft for proper bearing fit and clearances.

MCA Results - Summary Report

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Trend Reports

Greased Bearing

Replaced Bearing

Increased FrequencyIncreased Frequencyof Data Collectionof Data Collection

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FFT spectrum, cepstrum &demod

Triaxial, order-normalized data

Machine specific, statisticalbaselines

Feature extraction &exceedance tables

4700 fault templates

Score & trend specific faultseverities

Input

Vibration sensors

Accelerometers & proxprobes

Process andperformance data

Portable or Onlinesystems

OSI Pi Database

Internal Functions Output

Specific faults & severity

Repair recommendations

Email & pager ALERTs

Network replication

OPC & XML connectivity

Web Connect browseraccess

Automated Diagnostic SystemsAutomated Diagnostic Systems

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Incoming Spectra

Machinery Fault ReportMachinery Fault Report

What machine is this &what are its vibration sources?

How does this spectra compareto that of a healthy machine?

What, if anything, is wrong withthis machine and how bad is it?

Complete sets of high resolution vibe datafor FFT, cepstrum & demod

Machine configuration data,(VTAGs) coupled withcomponent specific fault templates

Detection diagnosis & prognosis

Automated Diagnostic System Flow Chart

Actionable Information

Feature extraction andexceedance table

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18 15Couplings

Component Codes

1Motor Driven

Close CoupledPumps/Fans

2Turbines

4Gearboxes

5Linked Drives(Belt/chain)

6Pumps

Centrifugal

7Rotary Thread

Pumps

8Sliding Vane

Pumps

9Axial Piston

Pumps

10Fans

11Centrifugal

Compressors

12Piston

Compressors

13Generators

14Centrifugal

Purifiers

NOTE:This illustrated set

is not complete

3Motors

3Motors

15Couplings

6Pumps

Centrifugal

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Features from comparison to baseline

AVERAGEAVERAGEAVERAGE AVERAGE + 1 SIGMAAVERAGE + 1 SIGMAAVERAGE + 1 SIGMAAVERAGE + 2 SIGMASAVERAGE + 2 SIGMASAVERAGE + 2 SIGMAS

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Extracted Forcing Frequencies

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Extracted Bearing Tones (3.1x)

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Fault Template Diagnosis Rules

Misalignment (Parallel)

1. 2X Radial or Tangential > 95VdB&

> 2 VdB above Baseline on both sides of the coupling

2. 2X Radial > 1X Radialor

2x Tangential > 1X Tangential for one side of the coupling

3. The Maximum 2X > 101VdBor

The sum of 2X exceedances > 18 VdB for at least one side ofthe coupling.

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CSDMCSDM

CSDMCSDM

CSDMCSDM

MOTORMOTOR

COUPLINGCOUPLING

CENTRIFUGAL PUMPCENTRIFUGAL PUMP

COMPONENTCOMPONENTCODESCODES

SCREENINGSCREENINGOUTPUT TABLEOUTPUT TABLE

(CSDM = Component Specific Data Matrix)(CSDM = Component Specific Data Matrix)

MACHINEDATA

MACHINEDATA

FAULTFAULTTEMPLATESTEMPLATES

Fault Models / Diagnostic Flow

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Results from Automated Diagnostics

Provides the most efficient machinery fault detection,diagnosis & prognosis to insure: Immediate local fault detection & actionable information

Optimal asset reliability and machine life extension throughprognosis of how & when machine should be repaired

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Rolling Element Bearing DetectionFault Indicators in Vibration Spectra

Bearing TonesNon-integer peaks and harmonicsrelative to component rotation rate

Sidebands

Noise floor elevation

High frequency indicatorsImpact and RingingModulation

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Snap ring groove

Inner race

Inner ring

Cage

Outer race

Outer ring

Seal/shieldgroove & notch

Bore

Inner ringface

Outer ringface

Outsidediameter

Ball

Rolling Element Bearing Geometry

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Bearing Tones

Pitc

hD

iam

eter

(PD

)

Ball Diameter (BD)

Ball Pass Frequency – Inner Race

BPFI

Ball Pass Frequency – Outer Race

BPFO

Ball Spin Frequency

BSF

Bearing Train Frequency

FTF

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Rolling Element Bearings

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Bearing Tones

Pitc

hD

iam

eter

(PD

)

Ball Diameter (BD)

BPFIn B

PRPM

BPFOn B

PRPM

BSFPB

BP

RPM

FTFBP

RPM

d

d

d

d

d

d

d

d

d

d

21

21

21

12

1

22

cos

cos

cos

cos

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Simplified Bearing Tones

Non-Synchronous Components BPFO = Rollers x rpm x 0.4

BPFI = Rollers x rpm x 0.6

FTF = rpm x 0.4

Sidebands Usually 1X Around BPFI

May be FTF Around Bearing Tones

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Rolling Element Bearings

For each shaft revolution:

4.6 balls will pass an outer race defect

The ball will make 2.02 revolutions

7.4 balls will pass an inner race defect

The cage will make 0.38 revolutions

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Calculated Bearing Tones

Bearing tones do not always appear at the expected,calculated frequencies

User does not always have correct bearing information

Diagnostic System designed to work independently ofcalculated bearing frequencies

User may overlay calculated frequencies on graph ifdesired

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Non-Synchronous Tones

Shaft Rotation

Shaft RateHarmonics

Bearing Tone 4.6 x

Sidebands 2.6x, 3.6x, 5.6x

0 1 2 3 4 5 660

70

80

90

100

110

120

130

140

Orders

VdBBearing Tone -- 4.6X

Synchronous Componentsare integer multiples ofshaft rotation rate

Bearing tones arenon-integer multiplesof shaft rate

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Automated Spectral Peak Extraction

Identify Shaft Rate Peak(s)

Identify Harmonics of Shaft Rate(s)

Identify Forcing Frequencies

Identify External Vibration

Extract non-defined, non-synchronous peaks aspossible bearing tone candidates.

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Summary of Analysis Techniques

Data Normalization


Cepstrum Analysis

Noise Floor Calculation

Rule-Based Diagnostics

Demodulation

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Cepstrum Analysis

The Spectrum of the Spectrum

0 10 20 30 40

CPM (x 1000)

60

70

80

90

100

110

120

130

140VdB

.006 .003 .002 .0015

Time, Seconds

60

70

80

90

100

110

120

130

140CdB

1X HarmonicsBearing Tones

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The Cepstrum

Extracts Periodicities From the Spectrum

Separates Different Harmonic Series

Separates Sideband Families

Is Useful in Automating Bearing Wear Detection

Bearing Model Is Not Required!!!

Is this bearing tone candidate part of a family of peaks?

“#” = “Yes”

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Spectral Data: Bearing Tone at 3.1x

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Put it all together (Cont’d)

3.1X 6.2X 24.8X9.3X

52.7X

15.5X12.5X

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Extracted Bearing Tones (3.1x)

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Data Normalization


Cepstrum Analysis



Demodulation

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High Noise Floor

0 2 4 6 8 10 12

CPM ( X 1000 )

60

70

80

90

100

110

120VdB

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Data Normalization


Cepstrum Analysis



Demodulation

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Amplitude Modulated Wave Form and itsSpectrum

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Bearing Impact Faults

High-Frequency Damped Oscillation

Acceleration Wave Form

Spall

Demodulaterd Waveform

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Amplitude Demodulation

Early Warning of Bearing Wear

Confirmation of Bearing Wear

Better Information on Which Bearing is Defective

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Diagnostic Report

FIRE PUMP #2Acquired: 8/19/03 10:35:38 AM 1xM = 1191 RPM Averages: 3RECOMMENDATIONS:MANDATORY: REPLACE MOTOR BEARINGSDIAGNOSES:EXTREME MOTOR BEARING WEAR

0.056 (+0.042) in/s at 3.11xM on 2A in low range0.028 (+0.025) in/s at 6.22xM on 2A in low range0.039 (+0.030) in/s at 9.33xM on 2R in low range0.079 (+0.077) in/s at 9.33xM on 2T in low range0.001 (+0.000) in/s at 24.8xM on 2A in high range0.088 (+0.084) in/s at 3.11xM on 2R in low range0.022 (+0.021) in/s at 15.5xM on 2R in high range0.022 (+0.011) in/s at 12.5xM on 2R in high range0.039 (+0.036) in/s at 3.11xM on 2T in low range0.001 (+0.001) in/s noise floor0.002 (+0.001) in/s noise floor0.001 (+0.001) in/s noise floor

MOTOR BALL BEARING DEMODBearing tone harmonics in demod spectrum with direct match between

regular and demod spectrum in 2R21 dB peak at 9.33x on 2R

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Progression of Bearing Faults

0 1 2 3 4 5 6

ORDERS

60

70

80

90

100

110

120

VdB Machine without Bearing Problems

11X

2X

3X4X

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0 1 2 3 4 5 6

ORDERS

60

70

80

90

100

110

120

VdB Slight Bearing Tones at 3.1X

1X

2X

3X4X

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0 1 2 3 4 5 6

ORDERS

60

70

80

90

100

110

120

VdB As defect worsens - 2nd harmonic rises

1X

2X

3X4X

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0 1 2 3 4 10 12

ORDERS

60

70

80

90

100

110

120

VdB Increased machine looseness - 1X harmonics increase

1X

2X

3X

4X

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0 2 4 6 8 10 12

ORDERS

60

70

80

90

100

110

120

VdB 1X Sidebands around the Bearing Tone

1X

2X

3X4X

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0 2 4 6 8 10 12

ORDERS

60

70

80

90

100

110

120

VdB “Haystack” in Noise Floor appears as Wear Progresses

1X

2X

3X4X

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Bearing Tone Sidebands

0 1 2 3 4 5 660

70

80

100

110

120

VdB

ORDERS

90

Bearing Tone

Sidebands spaced at FTF

140

130

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0 2 4 6 8 10 12

ORDERS

60

70

80

90

100

110

120

VdB Entire Noise Floor rises in advanced stages

1X

2X

3X

4X

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Key elements in a successful MCA

Information, not Data Measurement Methodology

Triaxial Data Collection with mounting pad (Complete data set &improved high frequency signal: Portable/Walk-around approach)

Superior Data Screening (Statistic baseline in hi/low freq range &automated, narrow band data comparison)

Analysis / Diagnostics / Prognosis

Automated Diagnostic Report with severity, fault and prioritizedrepair recommendation (information NOT just data)

Information Everywhere Distribution of Information

Simple, machine condition report/fault notification available via:

Internet or automated pager, email, text message

Delivering Machine Intelligence

mike cannon automated bearing dli engineering wear … auto bearing fault.pdf · 2016-08-04 · d l...

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