The Application of the Motor Current Signature Analysis in Diagnosis of Broken Rotor Bars in Squirrel Cage Induction Motors


Majid Malekpour

Motor Current Signature Analysis (MCSA) is a non-invasive method that is widely used for identifying both electrical and mechanical failures, capable to be performed online without disturbing the normal operation of the apparatus being monitored. Traditionally, the monitoring methods of rotor condition are based on frequency domain analysis of the stator current signal. When a BRB occurs, specific signatures will appear in the current spectrum at frequencies (1± 2ks)f , where f is the supply frequency, s is the slip and k = 1,2,... . Frequency domain analysis methods such as FFT, STFFT, Multiple Signal Classification (MUSIC), Root-MUSIC and Zoom-MUSIC are possible techniques for use to detect the side-band frequency components in the stator current spectrum.

Spectral leakage and spectral resolution are main difficulties associated with MCSA-based methods for analysis of rotor abnormalities in induction motors. At very low slip operating conditions, the fault characteristic frequencies are buried under the masking effect of the main frequency component making the detection of rotor bar defects difficult. Hence, aiming to eliminate the spectral leakage problem a new method has been developed and proposed in this paper based on the analysis of the instantaneous amplitude of the stator current.

Majid Malekpour received the B.Sc. degree from Shiraz University in 2007, the M.S.c degree from University of Kashan, in 2011, and the Ph.D. degree in electrical engineering from University of New South Wales, in 2018. He has one year hands on experience as an electrical engineer at Iranian Gas Transmission Company where he provided routine condition monitoring and fault diagnosis of electrical assets. His technical skills include motor current signature analysis (MCSA) method, Partial Discharge, and Dielectric Dissipation Factor (DDF) Analysis. He is currently working as casual academic staff at UNSW and National Institute of Dramatic Art (NIDA) in Sydney.