Arc-discharge mode and interruption performance in vacuum switch tubes

Arc phenomena in vacuum switch tubes involving the transition mechanism of the arc-discharge mode, and the relations among the arc-discharge mode, the electrode material, the electrode configuration, and the interruption performance are investigated. It is suggested that the positive ion accumulation near the anode causes the anode-spot mode transition. The floating shield potential and the arc voltage are related to the interrupting ability for the arcs between unslotted flat electrodes and between spiral electrodes, respectively. Through these fundamental research activities, a new line of compact vacuum switch tubes and new types of vacuum circuit breakers carrying them have been developed