Experimental analysis of a vacuum arc connected parallel to an arc in air

The vacuum arc is distinguished with many parameters from the arc in air. In some technical applications there occurs the question about phenomena which could be observed when an air arc will be connected in parallel with an arc in vacuum. The aim of the work is to present some experimental observations and discuss this problem. The experiments were performed in a laboratory circuit, in which an electrical arc burning in air was connected in parallel with a vacuum arc. The arc current had the oscillatory AC form with amplitudes of about 600 A, at supply voltages up to 1200 V. The vacuum arc was initiated in a special vacuum chamber, equiped with an ignition electrode, using high voltage triggering shortly after air arc initiation. The parameters of both discharges were observed, particularly the voltage and current flows after the time instant of the parallel commutation. The main question was the existence possibility of both these kinds of electrical discharge in the same electrical circuit. Experiments showed that in suitable circuit parameters, the arc in air is successfully extinguished by the vacuum arc. The discussion of observed phenomena are presented in the paper.