Apparatus and method for detecting stator winding groundwall insulation condition of inverter-fed AC motor

摘要

A method and an apparatus for monitoring an insulation condition of a stator winding of an inverter-fed AC motor are provided to monitor the insulation state by measuring a variable frequency signal and a leakage current using an inverter. An apparatus for monitoring an insulation condition of a stator winding of an inverter-fed AC motor includes first to third interrupter(60), a resistor, and a current measuring unit. The interrupters are inserted into respective signal lines to turn on/off each of 3 phase AC signal lines which are outputted from the inverter. The resistor is parallel-connected to one of the interrupters. When the interrupters are opened, the current measuring unit measures the current flowing through the resistor. When the interrupters are closed, the AC motor is connected to the inverter, so that the AC motor is activated. When the interrupters are opened, the current flowing through the resistor is measured, so that the insulation state of the winding of the AC motor is monitored.