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Vibration Condition Monitoring

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Vibration Condition Monitoring Overview of Methods Maintenance Methods Method Relative Cost Fix when fail 100% Preventive Maintenance PM 60% Condition Based CM ... – PowerPoint PPT presentation

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Title: Vibration Condition Monitoring


1
Vibration Condition Monitoring
  • Overview of Methods

2
Maintenance Methods
  • Method Relative Cost
  • Fix when fail 100
  • Preventive Maintenance PM 60
  • Condition Based CM 50
  • CM Failure analysis redesign 30

3
CM Methods
  • Method On load Off
    load
  • Visual, Hearing, Touching And Smell X X
  • Crack Detection X
  • Leak Detection X
  • Corrosion X X
  • Performance Evaluation X
  • Wear Particle Analysis X
  • Noise X
  • Acoustic Emission X
  • Electric Motor Testing X X
  • Lubrication X X
  • Thermal X
  • Vibration Condition Monitoring (VCM) X

4
Which machine?
  • Financial Analysis
  • Small power tools not cost effective
  • Major plant permanent monitoring?
  • Other machines regular screening?

5
Instrumentation
  • Transducer
  • Eddy Current (displacement)
  • Piezoelectric Accelerometer
  • Special SEE, SPM
  • Conditioning Amplifier
  • to suit transducer
  • built in to instrument
  • Readout/Analyser
  • Readout, band limited, FFT?

6
Accelerometer Mounting
7
Mounting Point
8
Measurement Location
  • Measure each vertical position for Trend Analysis
  • Measure all positions for full analysis,
    including Tacho / Phase
  • Convention number starting at driver

4V
3V
2V
4A
1V
3A
4H
2A
1A
3H
2H
1H
Tacho Phase
9
Machine Operation
  • Consistent operating conditions
  • Loaded, speed
  • How to detect loading?

10
OHS
  • Operator Safety
  • Location of transducers
  • Environment while measuring
  • Safety moving between machines
  • Emergency procedures
  • Personal safety equipment

11
Monitoring
  • Vertical vibration at each bearing
  • RMS vibration only
  • Use trend analysis
  • Full measurement at each bearing on fault

12
Trend Analysis
Vibration Level V RMS
Shutdown level
Full Measurement, Analysis Diagnosis
6 x base level
Alarm level
Repair
2 x base level
Time
13
Data, Route, Database
  • Record all data for all points
  • Regular logical route through plant
  • Data storage for maintenance intelligence
  • Data feeds back to monitoring/redesign

14
Vibration Level Assessment
15
Action at Alarm Level
  • CM measurement exceeds criterion
  • Fault diagnosis
  • Maintenance Plan
  • Spares Requisition

16
Rolling Bearings - Geometry
17
Bearing Defect Frequencies
18
Characteristic Spectrum
19
Plain Bearings
20
Characteristic Spectrum
21
Gear Faults
22
Characteristic Spectrum - Looseness
23
Characteristic Spectrum - Flow
24
Resonance
  • Input vibration that is at or near the natural
    frequency causes excessive vibration.
  • About 20 of machines show resonance
  • May occur with other faults
  • Can cause excessive energy use
  • Can cause serious damage

25
Diagnostic Case Studies

26
Case Study 1

27
Instrumentation
28
Rotor Details
29
Phase / Amplitude Data
30
Base Spectrum
31
Current Spectrum
32
Case Study 1
  • Data analysis confirms likely static unbalance
  • Consider the type of rotor to further examine the
    fault
  • Static unbalance is rare - fault means similar
    loss of mass at each end
  • (eg complete blade from a rotary planer)

33
Case Study 2

34
Machine Layout
35
Base Spectrum (3V)
36
Current Spectrum (3v)
37
Current Spectrum Better Resolution
38
Probable Fault
  • New spectrum bandwidth 5 Hz per line
  • Large vibration increase at TMF
  • Gear problem - perhaps excessive wear on one or
    both gears, failure of tooth hard facing etc.
  • Check 3H, 3A, 4V, 4H, 4A, 5V, 5H, 5A, 6V, 6H, 6A
    to confirm.
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