| 摘要 |
PURPOSE:To detect the shortcircuit of invertor arm earlier by a method wherein the series circuit of a capacitor or a capacitor and a resistor is provided in parallel with the invertor circuit between the current limiting reactor and the invertor circuit. CONSTITUTION:The invertor circuit 9 comprising the gate turn off thyristor GTO is provided with the output of the three phase AC power supply 1 through the intermediary of the smoothing reactor 10, the smoothing capacitor 3 and the current limiting reactor 4. The pulse supplying circuit 17 connected to the resistor 15 and the capacitor 16 in series is provided on the next step of said current limiting reactor 4 in parallel with said invertor circuit 9. The protective sequence circuit 13 is supplied with the output of the current transformer 14. Through these procedures for providing the pulse current supplying circuit 17, the shortcircuit current in case of a shortcircuit trouble may be detected at low set up level reducing the time to detect the shortcircuit trouble. |
