Break Arc Duration Characteristics and Arc Behavior Observations of AgSnO₂ Contacts in an Inductive Load Circuit Up to DC20V

Break arc duration characteristics of AgSnO<inf xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</inf> contacts were again studied with/without an external magnetic field of about B=150mT and at contact opening speeds from 1mm/s to 200mm/s. Break arc behaviors were also observed with a high-speed camera. Arc shortening effect due to magnetic field application was confirmed, not only with higher contact opening speeds and/or larger load current levels through magnetic arc blowing, but also in the cases with slower opening speeds and smaller current levels where magnetic blowing was not observed. Arc shortening effect to be caused by magnetic field application became less significant in the middle range of opening speeds than faster or slower speed ranges. That specific speed range was also meaningful for occurrence rates of magnetic blowing, since the rate started rising at such a specific middle speed range. Arc behavior observations confirmed that when arc was not magnetically blown out, arc was likely to finally extinguish while moving in the direction opposite to the Lorentz force direction. Certain different arc movements over electrode surfaces with/without external magnetic field application were also observed.