Measurements of the decay of arc column metperature following interruption

Gas temperature decay characteristics have been obtained for interrupted high-pressure arcs in air, nitrogen and argon at currents from 10 to 40 A and with carbon, copper and brass electrodes with gap separations of 2-10 mm. The characteristics are explicable in terms of simultaneous axial and radial thermal conduction loss, account being taken also of the depth of heat penetration into the electrodes. It is shown that the decay is characterized by a rapid fall of gas temperature from the arc value to the initial electrode temperature value. Following this a slower decay occurs at a rate determined by the cooling of the electrode mass.