Influence of Electrode Surface State and Electrode Thermal Parameters on the Motion of Magnetically Driven Arcs

The influence of electrode surface state and the electrode thermal parameters on the motion of magnetically driven arcs was investigated with the aid of high-speed photography, a surface profile recorder, and an electron scanning microscope. It was found that the electrode surface asperities had little influence on the arc velocities when the arc was moving in the direction of the electrode surface being polished. However, the asperities had appreciable influence on the arc motion when the arc was moving perpendicularly to the direction of polishing. An investigation on the local surface films on electrodes showed that the anode root of the arc can jump over a limited width of the local films. Furthermore, experiments on electrodes made of different materials showed that the thermal parameters of these materials exert a great influence on the motion of the arc.