Experimental Investigation of Alternating Current Arc Behavior and Associated Contact Welding Failure for General-purpose Relay

The contact welding failure of general-purposed relay closely relates to alternating current (AC) arc erosion. In this paper, AC arc behavior is investigated by a general-purpose relay firstly. The typical waveforms of arc voltage and current during contact making and breaking are presented, then the effects of point-on-wave (POW) at break on arc energy is analyzed explicitly. Based on the degradation processes of contact opening time and making heat occurred in the electrical endurance experiment, the possible physical mechanism of contact welding failure for general-purposed relay is proposed.