Voltage Distribution in the Stator Windings of High Voltage Motors Fed by PWM Drives Part II: Considering the Coil Arrangements

Previous studies of the voltage distribution across the stator windings of high voltage drive-fed induction motors are limited and focused on the voltage distribution among the turns of a single coil or across series coils. The variation of pulse rise time was considered as the only dominate characteristic of the applied pulse on the voltage distribution. In this article, effects of the side coils on the voltage distribution across series coils are assessed. This could model the mutual effects of the phases on their voltage distribution. To study the effects of the winding diagram on the voltage distribution, two stator windings with different winding diagrams and different nominal voltages and rated powers are used. The study is done by applying pulses with various rise times and pulse widths. The results demonstrate considerable effects of the voltage condition of the different phases, winding diagram and pulse width variation on the voltage distribution patterns and consequently the electrical stresses imposed on the insulation systems