JIC_V3_N1_RP4 Khadim Siddiqui Kuldeep Sahay V.K. Giri Journal on Instrumentation & Control Engineering 2321 – 1148 3 1 30 41 Mathematical Modelling, Pulse Width Modulated (PWM) Inverter, Induction Motor, Airgap Fault Detection and Identification, Time-Domain Analysis, Wavelet Transform In the present time, the inverter-driven induction motors drives are being widely employed in the industries for variable speed applications. These drives are replacing D.C. motors and thyrister bridges day to day in the industries. In the past, the Fast Fourier Transform (FFT) algorithm had been successfully implemented for the diagnosis of air-gap fault in the induction motor. This algorithm was used to diagnose various induction motor faults in the steady state conditions for constant load. However, the FFT algorithm is unable to detect induction motor faults in the transient condition. Therefore, early fault detection is not possible by this algorithm. Generally, the variable speed induction motors include large data size and FFT method is also not able to diagnose many faults for large data size. This research paper proposes a new technique for early air-gap fault diagnosis purpose. By using this technique, the air-gap fault may be diagnosed in the transient condition and fault may be averted before it becomes more catastrophic. As a result, industries may save large revenues and unexpected failure condition. In this research paper, an inverter driven induction motor model has been proposed and diagnosed for air-gap eccentricity fault in the transient condition by time-domain and time-frequency domain techniques. November 2014 - January 2015 Copyright © 2015 i-manager publications. All rights reserved. i-manager Publications http://www.imanagerpublications.com/Article.aspx?ArticleId=3423