Abstract: A vacuum switch having a fixed side electrode unit and a movable side electrode unit mounted in a vacuum vessel. Each electrode unit includes an arc electrode, an arc electrode supporting member for supporting the arc electrode, a coil electrode and a conducting rod. Joining portions between the arc electrode and the arc electrode supporting member, the coil electrode and the conducting rod are integrally and directly formed metallurgically by solid phase diffusion using a hot isostatic process. A vacuum circuit breaker may be constructed incorporating the vacuum switch.

Abstract: A vacuum circuit breaker comprising an external coil which is arranged outside a vacuum interrupter, and a power supply circuit which causes current to flow through the external coil. An overcurrent flowing through the main circuit of the circuit breaker, which leads to a load, is detected by an overcurrent tripping device so as to separate the movable electrode of the vacuum interrupter from the fixed electrode thereof and to subject a striking electric arc to a magnetic flux generated axially of the vacuum interrupter by the electrodes themselves. Thereafter, a trigger gap is ignited by a signal delivered from the overcurrent tripping device, so as to introduce a reverse current into the vacuum interrupter. Herein, the trigger gap is ignited by a signal delivered from the overcurrent tripping device, in order that the zero point of currents may be formed at the point of time at which the axial magnetic flux has been canceled by the resulting current of the external coil.