A Novel Technique for Induction Motor Rotor Broken Bars Diagnosis in Special Variable Speed Drives

Abstract

This paper deals with diagnosis of induction motor broken bar fault supplied from a special variable speed drive (VSD) equipped with an AC reactor and a sine-wave shaping filter on the output side, which could not be avoided due to vibration limits of the supporting construction. the proposed method is the instantaneous power spectrum analysis technique combined with the mean absolute difference (MAD) approach. The experimental results show that the instantaneous power spectrum analysis method is only effective when the motor is supplied from a sinusoidal supply, in contrast to the demonstrated VSD. The instantaneous power spectrums of the healthy rotor case and the broken bar rotor cases is processed with MAD algorithm to investigate the similarity between them. The results show that this combined technique is highly effective in diagnosis of broken rotor bar fault in case of the special VSD.