Broken Rotor Bar Detection in Induction Motors via Wavelet Ridge

On-line diagnostics of induction motor faults such as broken rotor bars can be accomplished by analyzing the anomalies of motor stator current. This paper presents a novel approach for the detection of the broken rotor bars in induction motors based on wavelet ridge. The characteristic frequency component(CFC) of the broken rotor bars is very close to power frequency in frequency domain but far less in amplitude in steady state, so it is very difficult to detect the broken rotor bars by Fourier Transform. As the CFC of the broken rotor bars approaches power frequency gradually during the motor’s startup process, the wavelet ridge-based method is introduced to analyze this transient procedure and the CFC of the broken rotor bars is extracted effectively. The influence of power frequency can be well eliminated, and the detection accuracy is greatly improved. Experimental results also demonstrate this is truly an excellent approach for the detection of the broken rotor bars.