Voltage Distribution in the Stator Windings of High Voltage Motors Fed by PWM Drives Part I: Effects of the Pulse Characteristics

Evaluation of the voltage distribution across the stator winding of the drive-fed induction motors is one of the most important criteria in the design of the insulation systems of stator windings. Voltage distribution across the stator windings of the low voltage drive-fed motors was studied completely. While, for the high voltage drive-fed motors it has been considered rarely. The output voltage of the PWM drives is formed by pulses with short rise times and various widths. Previous studies have considered the rise time of the pulses as the merely pulse characteristic which affects the pattern of the voltage distribution across the stator windings. In this article, the effects of the pulse width variation and rise time changing on the voltage distribution among the turns of a single coil and across the series coils of the high voltage motors were measured and evaluated. The results showed that the pulse width affects the pattern and amplitude of the voltage distribution more in comparison to the rise time of the pulses.