Patent ID: 7911303

Claim:
A circuit breaker comprising: a vacuum valve having a movable contact connected to an operating mechanism via a movable conductor, which is connected to an operating rod; an electromagnetic repulsion coil coaxially disposed around an axis of the movable conductor and the operating rod; and an electromagnet comprising a first coil for driving an operating shaft of the vacuum valve in an opening direction by an electromagnetic repulsion, a second coil connected to the electromagnetic repulsion coil and a movable iron core, a fixed core, and a permanent magnet, wherein the operating mechanism closes the vacuum valve when the first coil is excited, and holds the vacuum valve in a closed position by an attractive force of the permanent magnet, and wherein in a case of power failure, the second coil is excited in a direction opposite to a magnetic field formed by the first coil at the time of opening of the vacuum valve to open the vacuum valve within several milliseconds and the electromagnetic repulsion coil is excited simultaneously with the second coil.