Diagnostics of rotor faults in induction motors operating under time-varying load and light load conditions

The application of rotor fault diagnostics in an induction motor is always constrained to conditions that motors operating under constant and at least 25%of full load,due to the inherent limitations of DFT on time window and frequency resolution.This paper presents a simulation study of the detection of broken rotor bars using a modern spectral analysis technique when the motor is operating under time-varying load and light load conditions.Simulation result has shown that it is able to outperform DFT in the sense of achieving high frequency resolution while using significantly short data windows.An induction machine model is developed to generate stator current data for test.The model is validated with laboratory experiment