Diagnosis of Induction Motor Faults due to Broken Rotor bar and Rotor Mass Unbalance through Discrete Wavelet Transform of Starting Current at No-Load

The present paper proposes a method of diagnosis offaults o an induction motor due to broken -bar and massunbaLance rotor through analysis of its no-load stalling current. Stalling current is analyzed by di.screte wavelet transfbrm (DWI). The discrete wavelet coefficients are processed to determine the spectral energy fibr different spectral frequency bands containing the hamonics due to fault and statistical parameters of detail coefficients are calculated for different levels of wavelet for faulty and healthy motors. Tile parameters are used successfully for detection of fault in a motor. Advantage of this method is that it requires less computational time and less processing power. Also motor starting current being higher than the steady state current, this method does not require running the motor at load to obtain higher magnitude of current for better analysis. This method has been validated in a laboratory prototype.