| 摘要 |
PURPOSE:To enhance reliability by realizing automatic short circuit of surge current limiting element. CONSTITUTION:The hot-line inserting/pulling circuit is provided with a bypass capacitor C connected in parallel with an apparatus to be fed with a voltage, and a surge current limiting circuit 5b comprising a choke coil L1 for limiting the surge current Of the bypass capacitor C and a first relay contact rl1 for short-circuiting the opposite ends of the choke coil L1. The hot-line inserting/ pulling circuit further comprises a relay drive circuit 5a for driving the first relay contact rl1 to short-circuit the opposite ends of the choke coil L1 when the charging voltage of the bypass capacitor C exceeds a first reference voltage, and first and second reference voltage circuits 5c, 5d for setting hysteresis characteristics in the operation of the relay drive circuit 5a so that the choke coil L1 is released from shaft circuit when the charging voltage drops below a second reference voltage lower than the first reference voltage. |
