Patent ID: 6121571
Filing Date: 2000-09-19
Classification: H05H

Abstract:
A dc plasma arc generator comprising:a) an electrode, a first nozzle and at least one additional nozzle located such that plasma gas flows past said electrode, through said first nozzle and sequentially through said at least one additional nozzle, wherein said electrode, said first nozzle and said at least one additional nozzle are electrically conductive, and wherein said first nozzle and said at least one additional nozzle are sequentially connected electrically by parallel resistance and capacitance, wherein said sequentially connected resistance comprises at least one positive thermal coefficient resistor, the resistance thereof increasing with the passage of current therethrough such that the path of lowest electrical resistance for said arc migrates from said first nozzle sequentially through said at least one additional nozzle to the most downstream of said at least one additional nozzle; and,b) a dc power supply having a first terminal thereof connected to said electrode and a second terminal thereof connected to said most downstream nozzle; and,c) a source of high frequency power having a first high frequency terminal connected to said electrode and a second high frequency terminal connected to said most downstream nozzle, the high frequency power delivered by said high frequency power source being capable of igniting said arc.