Characteristic of the arc length and voltage in a DC Bi-Anode plasma torch

摘要

A special bi-anode plasma torch has been developed for elongating the arc length and obtaining the arc with a fixedlength. The relations between the arc voltage and the arc current were investigated for different gas compositions,and the effect of the gas flow rate on the arc voltage was also studied for the pure Ar plasma. The results show thatfor the pure Ar plasma, the arc voltage had a dropping characteristic for an arc with instable length and a risingcharacteristic arc voltage for an arc with fixed length, but for Ar-H2 plasma or Ar-N2 plasma, the arc voltage alwayshad dropping characteristic. Increasing the gas flow rate will enhance the arc voltage both for an instable and fixedlength arc.