Aging effects on the AC motor windings: A correlation between the variation of turn-to-turn capacitance and the PDIV

The presented paper focuses on monitoring of turn-to-turn insulation quality. It is based on the measure of the variation of the winding turn-to-turn capacitance and the Partial Discharge Inception Voltage (PDIV). The test methods is defined and described. Twisted pairs of three different diameters of enameled wires were tested. The PDIV is measured with an adequate system properly calibrated to minimize background noise to an acceptable value. Finally, it is shown an increased capacitance and a reduction PDIV between aging cycles. The correlation of these two parameters opens perspectives for preventive maintenance applications.