Rotor Bar Fault Diagnosis of Squirrel Cage Asynchronous Motors based on Adaptive Notch Filters

The fault characteristics of broken rotor bars in squirrel-cage asynchronous motors can be detected by the spectrum analysis of stator current, which, however, is difficult to realize since the fault signal is usually submerged by the fundamental components. Aiming to solve such problem, this paper introduces a method of rotor bar fault diagnosis of squirrel-cage induction motors based on adaptive notch filters. Firstly, adaptive notch filter is used to eliminate the influence of fundamental wave on fault characteristics. The Fast Fourier Transform is adopted to distinguish the suspected fault characteristic frequency. And the theoretical value of the fault characteristic frequency is calculated by the collected rotational speed information, and the rotor bar broken fault is then diagnosed by comparing the two values. The effectiveness and superiority of the proposed solution are finally verified by simulation studies.