Influences of Contact Opening Speeds and Magnetic Fields on Break Arc Behaviors of AgSnO2 Contact Pairs in DC Load Circuits

Both increases in contact opening speeds and application of external magnetic field are believed to be effective for realizing reductions in break arc durations. In this paper, AgSnO2 contact pairs were operated in a DC inductive circuit (L=10mH) with 1 to 20 A at 14V under different contact opening speeds of 1mm/s and 200mm/s and with or without magnetic field application of 100mT, and break arc durations were measured. As a result, both increased contact opening speed and applied external magnetic field surely caused certain shortenings of break arcs. However, each of them seems to exhibit different influences on metallic phases and gaseous phases, respectively.