PROJECT TITLE :

A Novel Online Stator Ground-Wall Insulation Monitoring Scheme for Inverter-Fed AC Motors

ABSTRACT:

Insulation failures are one among the foremost common failure modes of ac motors, notably high-voltage motors. Online monitoring of insulation health of ac motors is vital for preventing sudden outages and minimizing the associated monetary losses, significantly in important applications. Previously, an on-line ground-wall insulation monitoring technique has already been proposed for 6-lead ac motors. In this paper, a novel on-line ground-wall insulation monitoring theme is proposed for inverter-fed ac motors. This approach relies on measurement of common-mode insulation leakage current for online capacitance and dissipation factor (C/DF) monitoring. The proposed technique will be applied to both 3-lead and 6-lead ac motors and can also be extended to watch the insulation health of the cable connecting the inverter and the motor. The proposed technique is demonstrated within the lab environment and correlated with commonplace offline C/DF measurements.