Reignition current interruption characteristics of the vacuum interrupter

The high-frequency (70-600 kHz) current-interrupting capability of the vacuum interrupter has been investigated using an LC surge testing circuit. Three parameters were examined: di/dt, (di/dt)/gap, and Q×(di/dt)/gap, where Q is a quantity that represents the amount of residue between contacts at zero reignition current. It was found that Q×(di/dt)/gap is the most suitable quantity for indicating inherent high-frequency interruption characteristics of a contact material. This suggests that the residue between contacts plays an important role even at the moment of current interruption