Travelling Characteristics of Electromagnetically Driven Arc Burning between the Edges of Parallel Flat Electrodes in Atmospheric Pressure

Experimental investigation was performed on an electromagnetically driven arc burning between the edges of parallel flat electrodes in atmospheric pressure. A pair of parallel flat electrodes having a length of 640mm, a width of 20mm and a thickness of 1.2mm is set up horizontally with a gap length of 13mm. After new electrodes were arranged, the arc was sequentially ignited either 100 or 200 times in interval of 30 seconds. The result revealed that after reaching the local maximum at iteration number Ntest of 10-15, the travelling velocity of the arc slightly decreased with an increase in Ntest for all of the d. c. arc current la in the range from 36.5 to 117 A. The skipping number Nskip of an anode spot per unit length proved to lessen gradually with Ntest for Ia=36.5 and 48 A and to remain constant for Ia=65, 90 and 117 A. For instance, Nsiap decreased from 102 to 80 m-1 with increasing Ntest from 10 to 100 times for Ia=36.5 A, while Nsbp was kept at 36 m-1 for Ia=117 A. Accumulated amounts Ma of the anode erosion and Mc of the cathode erosion, respectively, were found to rise almost proportionally with Ntest for all of Ia and to reach 118 and 65 mg at Ntest of 200 times in case of Ia=117 A, respectively.