On-Line Current-Based Condition Monitoring and Fault Diagnosis of Three-Phase Induction Motor


A stator current measurement has an important role in condition monitoringand fault diagnosis of induction motors. For instance, the eccentricity, rotorbars and end ring breaks, shorted stator windings can be detected by analysesbased on stator current measurement. This paper addresses the application ofstator current spectral analysis technique for the detection and localization ofabnormal electrical and mechanical conditions that indicate, or may lead to, afailure of the induction motors. The effects of stator current spectrum aredescribed and the related frequencies are determined. In the presentinvestigation, the frequency signatures of some asymmetrical motor faults arewell-identified using signal processing techniques, such as Welch method forspectral density estimation. In fact, experimental results clearly illustrate thatstator current spectral analysis using Welch method is a very good tool todetect faults in induction motors. These faults are shaft speed oscillation,eccentricity, broken rotor bar, and end ring cracked.