Effect of Contact Materials on the DC Interruption Characteristics of a TMF Vacuum Circuit Breaker

Vacuum DC circuit breakers attract attention because of their advantages; fast operation speed and fire resistance. However, the low voltage of vacuum arcs and complex external circuits remain challenges. In this study, a transverse magnetic field (TMF) was applied to extend the arc length at the electrode ends, increasing arc voltage and enabling interruption using only the vacuum interrupter. The effects of electrode material properties were reflected primarily in magnetic driving time. AgWCCo material, with its superior evaporation characteristics and high thermal conductivity, demonstrated superior cutting performance in DC interruption under TMF application, while CuW material performed poorly. Fast interruption requires rapid arc drive to the electrode edge and rapid cooling of electrode temperature to prevent restrikes.