Vibration
VIBRATION MONITORING
WHAT IS VIBRATION ?
WHAT CAUSES VIBRATION ?
HOW DO WE MEASURE VIBRATION ?
HOW DO WE ANALYSE VIBRATION ?
Measurement direction – Horizontal, Vertical, Axial.
General rule of direction
- We measure H direction for machines on the foundation.
- We measure V direction for machines on structures
- We measure A direction when we suspect misalignment
- There are advantages, but there are exceptions to this rule.
Modes of Amplitudes
- DISPLACEMENT
- VELOCITY
- ACCELERATION
- SPIKE ENERGY
Physical Significance Of Vibration Amplitude
Displacement : Strain Indicator
Velocity : Fatigue Indicator
Acceleration : Force Indicator
The significance
- Displacement gives the strain energy
- Velocity gives the kinetic energy
- Acceleration gives the force
- Spike energy/HFD/gE are special ways to measure acceleration only.
UNITS OF MEASUREMENT
DISPLACEMENT – MICRONS
VELOCITY – MM / SEC.
ACCELERATION – MM / SEC2 , G
AMPLITUDE DESCRIPTORS
- RMS – Displacement, Velocity
- PEAK – 1.414 RMS Displacement, Velocity, Acceleration
- PEAK-TO-PEAK – 2 * PEAK Displacement
ISO 2372
Amplitude & Frequency
Amplitude:
It is the magnitude of Vibration signal.
Units: Micron, MM/Sec, M/Sec2
Frequency:
How many times oscillation is occurring for a given time period?
Units: CPS(Hz), CPM
