Evaporation speed affected by moving speed of vacuum arc cathode spot of copper

Abstract

It is important to prevent re-ignition after the arc interruption in the circuit breaker. A number of cathode spots generates, when the vacuum circuit breaker is extinguishing the arc in a vacuum. The cathode spot melt the cathode and the cathode is evaporated, because it has a high energy density. A metal vapor generated from the cathode spot becomes a factor of re-ignition when the transient recovery voltage is applied. Therefore, it is necessary to reduce the occurrence of metal vapor, controlling the moving speed of the cathode spot. The cathode spot will always move on the cathode, also changes the moving speed. Although the amount of input heat per unit area each moving speed is varied to change, the evaporation rate of the cathode is not clear. In this paper, the temperature distribution and the molten pool of area and temperature, the evaporation speed as a function of moving speed calculated by heat conduction simulation. As a result, the amount of heat flux unit area decreased with increasing the moving speed. Therefore, temperature of the molten pool and the evaporation speed decreased with increasing the moving speed.