Very low power plasma arc cutting equipment

Claim 1

An installation for controlling the operation of an arc gas welding or cutting torch, comprising an electrode and a nozzle axially movably mounted for movement relative to each other so as to achieve mutual contact when applied against a work piece in opposition to the action of elastically yieldable means for returning the electrode and nozzle to a mutual position in which the electrode and nozzle are spaced a maximum distance apart corresponding to normal operation of the torch, a welding or cutting electric current source, a welding or cutting current circuit connecting said source between the electrode and the work piece to be welded or cut, an arc gas source connected to the torch for supplying arc gas to the torch, said installation further comprising an auxiliary control circuit including a safety low voltage auxiliary source connected between the electrode and the work piece, an electric first means for causing the closure of a switch of the welding or cutting current circuit, which first means is adapted to come into action when there is a mutual contact between the electrode, nozzle and work piece, and second means acting in exclusive dependence on the welding or cutting current for maintaining said first means active.