Electric Characteristics of Plasma Arc Produced by Bi-Anode Torch

Abstract

In order to improve the voltage control and stability of a plasma arc, a new-type plasma torch was designed and constructed. The torch, called bi-anode torch, has two anodes that were inter-insulated and have different distances from the cathode tip. The position of the arc root can be controlled to attach to either anode surface during operation to obtain a low-voltage and high-fluctuation arc or a high-voltage and low-fluctuation arc. The paper discussed the occurrence of the double-arc phenomenon and its prevention. Experimental work has been carried out to compare voltage-current (U-I) characteristic of the arc when using different plasma gases and anode arc root attaching to different anode surfaces. The results show that the U-I characteristic of the plasma arc is affected by the position of the anode arc root attachment and the composition of the plasma gas, which was explained by a simplified arc model.