Abstract: The cutting or welding system includes a power source having, in one embodiment, a stabilization circuit for reducing arc rectification and, in another embodiment, a number of firing circuits for controlling the flow of current through a rectifier in order to more precisely provide a rectified alternating current. The power source also includes a rectifier having a number of current control devices for providing rectified current having alternating positive and negative cycles across the arc gap. Accordingly, the electrode alternates between an electrode negative state and an electrode positive state, respectively.

Abstract: An electrode and method of operating a plasma arc torch is provided which extends the useful service life of the torch. The electrode includes an elongate tubular holder defining a longitudinal axis and having a discharge end. An endwall closes the discharge end and includes an emissive insert. In one embodiment, the endwall also includes an annular sleeve which separates the insert from physical contact with the holder. Channels formed in the discharge end of the electrode direct a portion of a swirling vortex of gas across the surface of the endwall. The swirling vortex of gas removes products of erosion of the insert and adjacent portion of the sleeve such that the likelihood that arcing will transfer from the insert to the sleeve and/or holder is reduced, and the useful service life of the nozzle-electrode pair is thereby extended.