| 摘要 |
PURPOSE:To enable to suppress the neutral point of a synchronous machine and to reduce the ground resistance of the machine to small capacity by connecting a surge absorber at the rectifier side in noncontacting manner. CONSTITUTION:A rectifier side surge absorber 12a is connected in a noncontacting manner, and an inverter side surge absorber 16 is grounded. A rectifier side impedance to the ground contains only the floating capacity 11 of a cable, but the inverter side impedance to the ground contains the grounding resistance 9 of a synchronous motor 8, and the resulting impedance of the inverter side surge absorber 16 and the floating capacity 18 of the cable. The neutral point NM of the motor becomes completely ground voltage, and the current of the resistance 9 becomes zero. Since the neutral voltage NM is fixed, the terminal voltage of the motor does not rise and is advantageous in designing the insulation. |
