| 摘要 |
The timer starts on a power failure of distribution line and when the power failure is not removed within a fixed time, the circuit breaker is operated to lock out the failure section so that expansion of instantaneous power failure to permanent power failure is prevented. The automatic section switch includes a pulse generator (15) for generating pulses according to power condition, a counter (16) for executing a first counting by the first pulse signal nd for executing a second counting by the second pulse, a time delaying circuit (17) for resetting the counter when input powre condition becomes normal after one pulse generation by the pulse generator, and a reset circuit (18) for preventing trip coil operation before the second counting is started.
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