Patent Number: 6,794,601

Title: Plasma arc torch system with pilot re-attach circuit and method

Abstract: A plasma arc torch system, a circuit, and a method for controlling a pilot arc is disclosed. A rate of change sensor, such as a dv/dt sensor, monitors an output current signal or an output voltage signal to determine whether to close a switch to re-attach a pilot arc before a transferred arc becomes extinguished. The switch selectively connects a tip into a circuit path with an electrode and a power supply to allow the pilot arc to form between the tip and the electrode. A power supply preferably regulates the output current or voltage to a first level when a pilot arc is present, and to a second mode when a transferred arc is present.

Inventors: Norris; Stephen W. (New London, NH), Chamberlin; Roger (Sunapee, NH), Morrie; David (Claremont, NH)

Assignee: Thermal Dynamics Corporation

International Classification: B23K 10/00 (20060101); H05H 1/36 (20060101); H05H 1/26 (20060101); H05H 1/34 (20060101); B23K 009/00 ()

Expiration Date: 09/21/2021