An experimental study on influences of contact opening speeds on break arc characteristics of Ag and AgSnO_2 contacts

摘要

In a DC inductive load circuit (L=20mH) with a power supply voltage of DC 14V, break operations of a load current in the range from about 0.8 to 4 A were conducted with a Ag contact pair and a AgSnO_2 contact pair at contact opening speeds in the range from 0.5 mm/s to 20 mm/s. During the operations, break arc durations were measured and the average break arc duration was calculated in each operating condition. Although in general break arc duration is said to become shorter with a faster contact opening speed, no influences of contact opening speeds on average break arc durations were found for the Ag contact pair. For the break operations by the AgSnO_2 contact pair, the average break arc duration at larger load current levels became shorter with the increased contact opening speed from 0.5 mm/s to 5 mm/s, while no significant influences were recognizable with the faster speed range. Certain differences in arc voltage waveforms were also recognized for AgSnO_2 contacts operated to break 4A currents at difference contact opening speeds.