| 摘要 |
PURPOSE:To measre surely the insulation resistance of a DC motor in a short time by forming the discharge closed circuit of a capacitor through the DC motor. CONSTITUTION:An SCR2 for conversion from an AC to a DC, a capacitor 7 connected between the DC output bus of the SCR, the DC motor 4 supplied with the DC output of the SCR through a main circuit switch 3, an earthing switch 12 which earths one of the DC output busses by a closed path to form the discharge closed circuit of the capacitor 7 through the DC motor 4, a means 10 which detects the voltage of the capacitor 7, and a means 14 which obtains a discharge time constant of the capacitor 7 in accordance with the detected voltage to detect the insulation resistance of the DC motor 4 are provided. The capacitor 7 is charged for a prescribed time after opening the switch 3 to measure the insulation resistance. |
