INVESTIGATION OF A PLASMATRON WITH AN INTERELECTRODE INSERT

Results are reported of an experimental investigation of a plasmatron (plasma jet) in which cold air pumped into the gap between the insert and the output electrode was used as an insulator; as the effect of a single insert was found to be inadequate, a multiple insert was tried with mica insulation. The arc current-voltage characteristics and the air-enthalpy increase curve are presented, as well as a current-voltage characteristic of the nonselfmaintaining discharge between the positive column and the 4th insert. It is found that: (1) The interelectrode insert permits considerable increase in the arc length, arc voltage drop, and gas temperature, to provide a method for obtaining an ascending characteristic and for eliminating arc shunting: (2) The inserts connected to the power supply through isolating switches provide an additional possibility of adjusting the arc operation 'on the run,' with no adjustable power supply needed; (3) Gas supply distributed along the channel may provide an additional opportunity for improving arc characteristics. (Author) Edited trans. of Akademiya Nauk SSSR. Sibirskoe Otdelenie. Izvestiya, n10 Seriya Tekhnicheskikh Nauk, n3 p56-62 1965, by H. Peck.