Diagnosis of Broken Bar Fault in Induction Machines Using Discrete Wavelet Transform without Slip Estimation

The aim of this paper is to present a wavelet-based method for broken bar fault detection in induction machines. The frequency-domain methods which are commonly used need speed information or accurate slip estimation for frequency components localization in any spectrum. Nevertheless, the fault frequency bandwidth can be well defined for any induction machine due to numerous previous investigations. The proposed approach consists in the energy evaluation of this known bandwidth with time-domain analysis using the discrete wavelet transform (DWT). Then, it has been applied to the stator current space vector magnitude and the instantaneous magnitude of the stator current signal for different broken bar fault severities and load levels.