Stabilization control manner null of purazumaa - ku in purazumaa - ku

摘要

PURPOSE:To generate stably always a pilot arc against the variation in power source voltage by keeping stably on the fixed level the pilot current which is passed through the cable run for pilot arc generation after the generation of the pilot arc. CONSTITUTION:A cutting current Ic is not passed at the moment generating a pilot arc between electrode 3 and nozzle 4 by high frequency generating device 7 and only pilot current Ip is detected by arc current detecting means 13. The feedback control system controls at constant current the pilot current Ip to the reference set value set in advance by setting means 12. The cutting current Ic is passed to cutting current detecting means 14 when plasma arc 8 is generated by approaching a plasma torch 2 to the material 6 to be cut after generation of the pilot arc. When this reaches the set level, the reference set value of the setting means 12 of the control set value is changed to Ia.