Patent ID: 6670572
Filing Date: 2003-12-30
Classification: H05H

Abstract:
A method of operating a contact-start plasma arc torch system, said torch system including a torch activation switch indicating desired operational states of the torch, a power supply having first and second output terminals and selectively supplying an output voltage therebetween, a plurality of contact start elements, a first one of the plurality of contact start elements being in selective electrical communication with the first output terminal, and a second one of the plurality of contact start elements being in selective electrical communication with the second output terminal, said method comprising:monitoring the torch activation switch and determining if the desired operational state of the torch transitions from an off state to an operating state; causing a condition allowing a closed electrical circuit to be established between the plurality of contact start elements; sensing a closed electrical circuit condition between the plurality of contact start elements; opening a gas control switch and providing a flowing gas to be ionized upon sensing the closed electrical circuit condition between the plurality of contact start elements; sensing an open electrical circuit condition between the plurality of contact start elements after opening the gas control switch; and closing the gas control switch and removing the flowing gas if the open electrical circuit condition is sensed between the plurality of contact start elements after the flowing gas has been provided.