On the Electrical Characteristic and Heat Dissipation of High Voltage Surface Arcs

This paper provides results of investigations to the electrical characteristics and heat dissipation of low current, high voltage surface arcs at AC and DC voltage. Several influencing factors on arc parameters are investigated. The current-voltage-characteristic of the high-voltage arcs are non-linear with the typical increasing voltage demand with decreasing current. The voltage demand decreases with decreasing electrode distance nearly linearly. An influence of the electrode material can be noticed only with a liquid electrode at DC-. It was found, that the electrical power of the DC arcs is approximately 15 % to 20 % higher in comparison to AC. The heat dissipation of AC and DC arcs are examined on a ceramic specimen. The specimen's surface heating is by about 15 % to 20 % higher at DC in comparison to AC. Further, contrary to AC, the heat distribution is nonuniformly with a maximum at the cathode. Reducing the DC current to an equivalent power consumption leads to similar temperature levels at AC and DC.