| 摘要 |
PURPOSE:To enable to discriminate the insulation deterioration of a rotor winding position in on-line by detecting the deterioration generated at a rotor winding position as the AC component of an insulating current, and calculating the insulation resistance value of the rotor winding position from the AC component. CONSTITUTION:When a ground occurs in a DC motor 1, an AC component is extracted from a ground current from ground-fault current detecting means 7 by a band filter 18 on the basis of an alternating frequency of a rotor detected by frequency detecting means 8, rectified by a rectifier 19, an insulating resistance value is calculated on the basis of a signal in response to the AC component from the rectifier 19 and a signal in response a voltage value of a DC power source from circuit voltage detecting means 9, and the insulation resistance value of the rotor winding position is obtained by considering the voltage value of the DC power source and the alternating frequency of the rotor. |
