Effectiveness of Current Envelope analysis to detect broken rotor bar and inter turn faults in an inverter fed induction motor drive

Abstract

In the present industrial scenario, machinery reliability and maintainability plays very important role in meeting the tight production schedules. In such systems, unexpected failures need to be minimized by effective fault diagnosis methods. Induction motors are used as prime movers in most industrial machinery. Therefore, effective fault diagnoses of induction motors are vital in achieving the minimal downtime and production targets. In this work, a comparative study between spectrum analysis of an Enveloped signal with that of traditionally used Fast Fourier Transformation (FFT) of motor current i.e. Motor Current Signature Analysis (MCSA) is performed. Nowadays, Inverter fed drives are commonly used for speed control operations. These drives generate noise and harmonics in the supply line which hinders the MCSA in fault detection. This paper investigate the effectiveness of MCSA and Current Envelope analysis for detection of broken rotor bar and inter turn fault in an inverter fed induction motor drive. A simulation based technique with addition of noise of low Signal to Noise Ratio (SNR) which serves as a replica of phase current in an inverter fed drives is followed.