Motor Insulation Aging Diagnosis with Pre-Installed Current Sensors for Inverter Control

In order to avoid a sudden failure of equipment, online diagnosis technique of motors is desired. To develop an insulation aging diagnosis technology using pre-installed current sensor, waveform of pre-installed current sensors is recorded for several insulation aging conditions. Initial and late insulation aging conditions are simulated by connecting the several capacitors to the motor. By comparing the Lissajous figure of each insulation aging state, it was revealed that the Lissajous figure became thicker as the insulation aging states progressed. Local Subspace Classifier was applied as a method to calculate the degree of abnormality of the changes of Lissajous figure and confirmed that LSC was able to detect the rise in abnormality degree due to progression of insulation aging.