Influence of Electrode Width upon the Instantaneous Velocity of Traveling AC Arc Between a Pair of Parallel Conductors

Abstract

An arc occurred between a pair of parallel conductors is driven by the electromagnetic force. Such traveling phenomena of arcs are found in low voltage circuit breakers, switch boxes or panel boards at accidental condition. Until now, these study have been reported only for relatively low current level, and there are few study for short circuit large current level. Also, the traveling velocity of the arc reported was an average value through whole arcing time. This paper describes the experimental results on the traveling arc between a pair of parallel conductors for alternating current from 600 to 1, 100 A(rms.) with a frequency of 60Hz. The material of conductors is copper and the gap of the two conductors is 15mm. The arc velocity and the arc extinguishing properties are studied. Measurements were made on the average velocity through traveling period and also the instantaneous velocity at each phases of the sinusoidal current. The instantaneous velocity ranged from 2 to 65 m/s and showed a proportional expression to the power of current, same as the average velocity case. Influences of shape of the electrode especially its width upon the arc length, traveling velocity and extinguishing properties were clarified.