Abstract: A circuit breaker includes a vacuum valve, an electromagnet including a first coil for driving an operating shaft of the vacuum valve toward an opening direction by electromagnetic repulsion, a movable core and a permanent magnet. Further, an operating mechanism is provided which excites the first coil to close the vacuum valve, holds the vacuum valve closed by an attractive force of the permanent magnet and excites the first coil in a direction reverse to an excitation direction in closing operation to open the vacuum valve. In the circuit breaker, together with the first coil, a second coil is disposed which is excited simultaneously with an electromagnetic repulsion coil for a quick opening operation by electromagnetic repulsion is provided in the electromagnet.

Abstract: A circuit breaker comprising a vacuum valve; an electromagnet including a first coil for driving an operating shaft of the vacuum valve toward an opening direction by electromagnetic repulsion, a movable core and a permanent magnet; and an operating mechanism which excites the first coil to close the vacuum valve, holds the vacuum valve closed by an attractive force of the permanent magnet and excites the first coil in a direction reverse to an excitation direction in closing operation to open the vacuum valve. In the circuit breaker, together with the first coil, a second coil which is excited simultaneously with an electromagnetic repulsion coil for electromagnetic repulsion in quick opening operation by electromagnetic repulsion is provided in the electromagnet.

Abstract: A power use circuit breaker includes an arc generating switching unit which adds an electrical resistance in a circuit during current interruption to attenuate a current to be interrupted, a vacuum bulb which is electrically connected in series with the arc generating switching unit and interrupts the attenuated current and a current conducting switching unit connected in parallel with the series circuit of the vacuum bulb and the arc generating switching unit. For current conduction the current conducting switching unit is closed after the vacuum bulb and the arc generating switching unit are closed, and for current interruption after opening the current conducting switching unit, the vacuum bulb and the arc generating switching unit are opened.

Abstract: A power use circuit breaker includes an arc generating switching unit which adds an electrical resistance in a circuit during current interruption to attenuate a current to be interrupted, a vacuum bulb which is electrically connected in series with the arc generating switching unit and interrupts the attenuated current and a current conducting switching unit connected in parallel with the series circuit of the vacuum bulb and the arc generating switching unit. For current conduction the current conducting switching unit is closed after the vacuum bulb and the arc generating switching unit are closed, and for current interruption after opening the current conducting switching unit, the vacuum bulb and the arc generating switching unit are opened.

Abstract: An arc generating switching unit 2 which adds an electrical resistance in a circuit during current interruption to attenuate a current to be interrupted, a vacuum bulb 1 which is electrically connected in series with the arc generating switching unit 2 and interrupts the attenuated current and a current conducting switching unit 3 connected in parallel with the series circuit of the vacuum bulb 1 and the arc generating switching unit 2 are provided, and for current conduction the current conducting switching unit 3 is closed after the vacuum bulb 1 and the arc generating switching unit 2 are closed, and for current interruption after opening the current conducting switching unit 3, the vacuum bulb 1 and the arc generating switching unit 2 are opened. Thereby, a small sized power use circuit breaker which performs current conduction and interruption of a large current containing a DC component is obtained.