ELECTRODE TEMPERATURES OF CARBON AND GRAPHITE ARCS

Measurements of the electrode temperatures for arcs operating in room air over a current range of 5-30 A are given. A distinct difference in the peak temperatures of the radial distributions for graphite and carbon cathodes has been observed, the values being 4150 and 3500°K respectively. Using the Richardson-Dushman equation approximate values of the corresponding peak cathode electron current densities have been calculated and these are given as 4000 and 700 A cm-2. Radial temperature profiles for the graphite anode are also given for the same current range.