文档介绍：Condition Monitoring
& Vibration Fundamentals
What is Condition Monitoring ?
Monitoring Parameters Noise !
What else?
Temperature Pressure
Output Speed
Phase Vibration
Motor Current Oil Quality & Condition
Casing Expansion Differential Expansion
Eccentricity Rotor position
Valve position
Types of Monitoring
Machines faults - Potential Failure Modes
Unbalance Lubrication ponent Belt
Oil contam defects resonance vibrations
Mis- Gear mesh Stator Rotor- Bearing
alignment defect defect defect defect
Temperature
X X X X X X X X
Acoustic
X X X X X X XX
Oil Analysis
X X X X X X X
Vibration
Vibration Fundamentals
Acceleration
Vibration Measuring Units (180 deg phase lead)
Acceleration, a
Velocity, v = a / 2 f
Velocity
(90 deg phase lead)
Displacement = a/4 2 f 2
Displacement
Vibration Fundamentals
Decibel Reference Levels (ISO R 1683)
Measured Level
For Amplitude Rations:
N (dB) = 20 log10 ( a / a ref)
Number of Decibels Reference Level
-6 2
Vibratory Acc. Level La = 20 log10 ( a / a o)a o = 10 m/s
-9
Vibratory Vel. Level Lv = 20 log10 ( v / v o)v o = 10 m/s
Vibration Transducers
Sensors…Transducers…Probes…What is it?
….It basically converts mechanical vibration
to an electrical signal
Accelerometer Velocity Displacement
Charge Type & Transducer Shaft Riders
Line Drive Proximity Probes
Constant Voltage & (Eddy Current Probes)
Conatant Current
Typical Uses of
Vibration Transducers
Radial Shaft
Vibration & Position
Radial Casing
Vibration
Axial Shaft
Vibration & Position
Frequency Range
30
dB Useful Frequency Range
20 10% limit - 3dB limit -
10
Frequency Response of Sensor
0
-10
-20
Relative Sensitivity
-30
-40
2Hz 10KHz
Frequency [xf0]
Consider…Sensor…Instrument…Cables…Sensor Coupling
Sensitivity vs Frequency Range
Sensitivity
Frequency
Monitoring Techniques
Relative Amplitude
Useful Operating Ran