低圧気中開閉器におけるDCアークによる開極開始直後の銀接点消耗特性

抄録

This paper describes a basic mechanism of Ag contact erosion by DC arc at the beginning of the contact break in low-voltage switch. We focused on the relationship between the contact erosion and the arc duration, and found that there is the contact erosion M_b, which is generated immediately after the start of break and does not depend on the arc duration but depends on approximately square of the current at the start of break. We considered that the M_b is the contact erosion due to the bridge formation at the beginning of the break, and the bridge formation depends on electrode heating at the final contact point. We also clarified the rate of the contact erosion at the beginning of the break is large against the total contact erosion. Especially, this rate reaches 90% in maximum case of this paper.