Estimation of Contact material in Vacuum Circuit Breaker

In order to evaluate the performance of a vacuum circuit breaker, we have investigated measurement of chopping current and their related values, and nonsustained disruptive discharges (NSDD) by using AgWC25, AgWC35, CuW-Sb and CuCr electrodes. We have measured the current chopping phenomena and optical spectroscope measurement and their decay of neutral metal at current chopping, and a kind of dielectric strength NSDD of vacuum interrupter. As results, the generating frequencies of NSDD, CuW-Sb electrode is the lowest value and their performance when circuit breaker is operated in the system is very good because of low voltage switching surge. On the contrary AgWC35 electrode was the highest value and its performance for switching would give the worst condition. After the test, we observed electrode surface and we found out metallic protrusion of the surface of AgW-Sb was relatively large. For the chopping current, we observed spectroscopic measurement at current chopping for a neutral vapor and the rate of change of decay at current chopping was very much related and more over chopping current for AgWC35 was the lowest value among the tested electrode material