Modeling and characterization of induction motor internal faults using finite element and discrete wavelet transforms

This paper examines the behavior of three phase induction motors with internal fault conditions under sinusoidal supply voltages. Two types of induction machine internal faults are investigated, rotor broken bar, and stator shorted turns faults. Early detection and diagnosis of these faults are desirable for condition assessment, maintenance schedule and improved operational efficiency of induction motors. The terminal behavior of the induction motor was obtained by coupling the induction motor transient FE model and external electric circuit. Such a model would allow efficient representation of the induction machine with internal faults. A discrete wavelet transform (DWT) was then used to extract the different harmonic components of the stator currents. The key advantages of the DWT are its ability to provide a local representation of the nonstationary current signals for normal and faulty operating conditions.