Relationships between Contact Opening Speeds and Arc Extinction Gap Lengths at Break of Silver Contacts

抄録

In order to study the influences of contact opening speeds on arc extinction gap length characteristics, Ag contacts were operated to break DC inductive load currents from 0.1A to 2.0A at 14V with contact opening speeds of 0.5mm/s, 1mm/s, 2mm/s, 5mm/s and 10mm/s in a switching mechanism employing a stepping motor, and arc voltage waveforms were observed at each opening of the contacts. From the results, the average arc durations were determined at each current level under the respective contact opening speeds, and the average arc extinction gap lengths were calculated by multiplying the average arc duration value and the contact opening speed value. It was found that average arc durations showed no significant differences with increasing contact opening speeds. Thus, arc extinction gaps became larger at faster opening speeds in the inductive load conditions of this study.