Standoff control method and apparatus for plasma cutting machine

摘要

The invention is directed to a standoff control method for oa plasma cutting machine in which the arc voltage across and electrode of a torch or a nozzle surrounding said electrode and a work to be cut is detected so as to control the standoff between said torch and said work to be cut to a predetermined value in accordance with the detected voltage, said standoff control method for a plasma cutting machine comprising the steps of: continuing an operation by a safety control in which said torch is positioned away from said work to be cut by a predetermined quantity until a double-arc disappears if the Generation of said double-arc is detected as a result of a detection of a voltage drop across said nozzle and said work to be cut, and cancelling said safety control and making a restoration to a normal torch control after the voltage has been restored to an original level.