Measurement of machine vibrations by using a fast rotating magnetic field

A synchro and a fast rotating magnetic field (RMF) based technique is developed in this paper for the measurement of machine vibrations. The RMF is used to measure the velocity of these vibrations with high resolution. A new strategy is applied by transmitting the machine vibrations to the rotor of a synchro and measuring them in terms of pulses of different pulse widths. A broad spectrum of pulses is obtained corresponding to instantaneous velocities of vibrations. The effectiveness of the developed vibration measurement technique is verified by experimental tests on a dc motor. Test results show that the developed method measures all possible instantaneous velocities and peaks of machine vibrations accurately within millisecond range which are missed by conventional methods. Hence the technique is very useful for an early fault diagnosis and overall condition monitoring of the machines.