T. G. Arora - Department of Electrical Engineering, Shri Randeobaba College of Engineering and Management, Nagpur, India.
M. V. Aware - Department of Electrical Engineering, Visvesvaraya National Institute of Technology, Nagpur, India.
D. R. Tutakne - Department of Electrical Engineering, Shri Randeobaba College of Engineering and Management, Nagpur, India.

Pulse-width modulated (PWM) adjustable frequency drives (AFDs) are extensively used in industries for control of inductionmotors. It has led tosignificant advantages in terms of the performance, size, and efficiencybut the output voltage waveform no longer remains sinusoidal. Hence, overshoots, high rate of rise, harmonics and transients are observed in the voltage wave. They increase voltage and thermal stresses; resultinginto accelerated insulation aging. This paper presents the application of fuzzy logic to life estimation of PWM driven induction motors. Insulationstress parameters are experimentally computed for wide range of switching frequency and used in fuzzy logic based life estimation algorithms. The results obtained with the fuzzy expert system show a performance approaching that attainable for the life model based on the inverse power law

Insulation aging Life model Peak voltage Thermal stress