Vibration signal analysis of induction motors used in process control operation

The present work, propose a system for vibration signal analysis of 3-phase induction motor when controlled by Variable Frequency Drive (VFD), in process control operation. The motors used in process control operation are subjected to dynamic speed along with load variations, thus most often fault occurs in rotating elements such as bearing. In literature, various bearing fault identification technique has been proposed with the help of time and frequency domain based features, most of these technique were tested in laboratory under fixed rotating speed and or fixed load. On the other hand influence of external vibration on the vibration signature not been studied in depth, which are very important mainly for the motors used in process plant. The present study revealed that identification of bearing faults harmonics with the help of accelerometer sensor during operation becomes difficult due to dynamic variation of speed, load, and mostly presence of non-stationary background vibrations, therefore some intelligent condition monitoring system is required for robust identification of faults.