Dependence of repeated a.c. arc ignition on physical characteristics of material serving as a cathode

Dependence of a.c. arc ignition voltage on physical characteristics of cathode material has been studied. A tungsten rod served as the first electrode, and plates made of steel, pure titanium, zirconium, niobium, vanadium, molybdenum, tungsten, and tantalum, in turn, served as the second electrode. It has been established that, aside from a magnitude of atom ionization potential of electrode metae repeated arc ignition voltage is also determined by cathode material emissivity, excitation potential of the atom first metastable level, and vapour pressure of the material