Detection of Dynamic Eccentricity Fault in Induction Motors Using Fast Fourier and Wavelet Packet Transform Methods

This paper presents the effect of rotor dynamic eccentricity fault on the air gap magnetic field and stator current in a tested ۳ phase squirrel cage induction motor. The distorted sinusoidal stator current is analyzed by Fast Fourier transform and wavelet packet transform methods to detect the fault. The magnetic fields in the stator, rotor and air gap are simulated using Finite Element Magnetic method. To achieve accurate model, all geometrical, electrical, mechanical, and physical characteristics of different parts of induction motor are considered in the model and the obtained results confirms this issue. To zoom on a particular frequency interval, the wavelet packet transform method is employed. The presented simulation results show although both methods wavelet and Fourier transforms are capable to detect the dynamic fault in the motor, though wavelet transform indicates the fault more clearly.

Keywords:

Dynamic eccentricity , Fast Fourier transform , Fault detection , Induction motor , Wavelet packet transform