| 摘要 |
PROBLEM TO BE SOLVED: To suppress the generation of an arc when a relay is driven, to reduce the size of the relay and to prevent a device from being destructed due to overvoltage generated when power is restored. SOLUTION: The voltage regulating device is constituted of a transformer 2 inserting a secondary winding 2b into an AC line, an AC chopper 3 for outputting voltage to the primary winding 2a of the transformer 2, a normally opened relay MC1 inserted into the input line of the chopper 3 in series, a normally closed relay MC2 connected to the primary winding 2a of the transformer 2 in parallel, a voltage comparator 5 for judging the value of control voltage Vc outputted from a control power supply device 6, and a control device for controlling the chopper 3 and the relays MC1, MC2. When service interruption is generated, the chopper 3 is turned to an electrically direct sending state, the relays MC1, MC2 are driven, and when power is restored, the chopper 3 is driven after starting the drive of the relays MC1, MC2 and voltage is applied to the primary winding 2a of the transformer 2.
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