Broken rotor bar detection in induction motor via stator current derivative

The fault of broken rotor bars in a three phase induction motor is diagnosed by using the wavelet multi-resolution analysis in this paper. Daubechies wavelet is selected as the wavelet base and the wavelet coefficient is obtained from the wavelet transform of current derivative signal of the faulty induction motor. The wavelet reconstruction of a signal branch is processed. The signals energy in different levels is compared together. Simulation result show that different broken rotor bar have different energy in level three. Based on this number of broken rotor bar is obtained.