Influences of contact opening speeds on break arc behaviors of AgSnO_2 contact pairs in DC inductive load conditions

摘要

Break operations of a DC inductive (L=20mH) current at about 1A, 3A and 5A with 14V were conducted with AgSnO_2 contact pairs under different contact opening speeds of 0.5, 2, 20 and 200mm/s in air. Average break arc duration at each current level was calculated under the respective opening speeds. At 1A, the average break arc durations were not influenced by the contact opening speeds, while the arc durations became shorter with increases in the opening speeds at 3A and 5A. However, such reduction tendencies were less significant with an increase of the contact opening speed from 20mm/s to 200mm/s, even when operated to break a load current of 5A. Furthermore, based on observations of break arc voltage waveforms, metallic phase durations were found to become shorter with increases in the contact opening speeds.