Vibration pickups
From the information given so far it will be appreciated that exactly how the vibration is measured and the equipment used becomes of prime importance. The actual “pickup” or transducer is a sensing device which converts the mechanical vibration into electrical energy. Several types exist as follows:
Seismic velocity pickup
This consists of a coil of wire supported by springs in a magnetic field created by a permanent magnet which is part of the case. For details of the construction see Figure 15.7.
When it is held against or attached to a vibrating machine, the permanent magnet, being attached to the case follows the vibratory motion. The coil of wire or conductor being supported
COMPRESSION TYPE |
Triangular Centre Past |
Preloading Ring Piezoelectric Element in Shear Seismic Hass |
SHEAR TYPE |
Function of frequency squared they are most sensitive to high frequency vibration.
Posted in Fans Ventilation A Practical Guide