| 摘要 |
PURPOSE:To extend the lives of an electrode and a nozzle and to provide the stabilization of a pilot arc and the reduction in the size of a electric power source for the pilot arc by decreasing the pilot arc current of a plasma torch of a transfer type. CONSTITUTION:The plasma torch arch 10 of the transfer type consists of the pilot power source 40 which superposes the DC output necessary for the pilot arc A and the high-frequency output necessary for firing of the pilot arc A on DC output and supplies the electric power and a main power source 30 which supplies the electric power necessary for the main arc B. The power source 40 is changed over to the DC output necessary for firing the arc A and the DC output decreased to about the output necessary for maintaining the arc A to limit the pilot arc current after firing of the arc A and to control said current so as to maintain the discharge thereof. |
