Probe Measurements and Potential Distribution in Copper A-C Arcs

A previous paper on a-c arcs in air between copper electrodes showed the influence of circuit constants in determining the rise of voltage across the electrodes during the reignition period of cyclic current zero. This paper gives the distribution of potential throughout the arc space between the electrodes during the reignition period, and shows that during that time the potential drop is concentrated largely in the space adjacent to the cathode, the major portion of the arc space is free from potential gradient, and the potential distribution is measurable with fidelity by means of inserted probes.