A new method of non-stationary signal analysis for control motor bearing fault diagnosis

We present an equal phase sampling method (EPSM) based technique to diagnose nonstationary servomotor bearing faults. Conventional equal time sampling method (ETSM) is based on the time periodical feature of a constant rotating speed system. As the servomotor changes its rotating speed and direction frequently, it will loose its time periodical feature. However, it still keeps its space periodical feature. The new method of nonstationary signal analysis based on EPSM can eliminate the influence of rotating speed and direction changes. The mathematical simulation and experiment results prove that this method is very suitable and effective for servomotor bearing fault diagnosis.