When multi-axial accelerations at a point are to be measured, each acceleration transducer axis should pass within 10 mm of that point, and the centre of seismic mass of each accelerometer should be within 30 mm ofthat point.
The equipment, that is used for measurement of vibration consists of transducers, amplifiers, frequency weighting filters, averaging networks and a kind of recording device.
The most suitable transducer for vibration measurement is the accelerometer, which produces a voltage or charge at its terminals that is proportional to the acceleration which it is exposed to.
The most common type of accelerometer is the piezoelectric type. The figure below shows a compression type piezoelectric accelerometer - when the accelerometer vibrates, the seismic mass exerts a reaction compressive force on the piezoelectric element. Compression of the seismic mass generates an electrical signal which is proportional the acceleration of the accelerometer. The electrical output from the accelerometer can then be translated into a vibration reading.
