| 摘要 |
PURPOSE:To safely and effectively drive an electric railcar even when a field chopper becomes defective by disconnecting a shunt winding from the chopper and connecting in parallel with a main resistor. CONSTITUTION:When a chopper 9 becomes defective or a freewheeling diode 8 is damaged, a switch 11A is disconnected and switches 11C, 11D are switches. Thus, a shunt winding 3f is connected in series with an armature circuit, and a main resistor 4 is connected in parallel. Since the power drive characteristic of this circuit becomes series motor characteristic, it can be normally power driven. |
