The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Mar. 22, 1994
Filed:
May. 19, 1992
Jeffrey L Peterson, Lebanon, NH (US);
William V Bailey, West Lebanon, NH (US);
Hypertherm, Inc., Hanover, NH (US);
Abstract
A high frequency, high voltage starting circuit for a plasma arc cutting torch is operated in pulses to restart the torch if an initial arc extinguishes before the arc transfers to the workpiece. The starting circuit includes a D.C. power supply with its negative output connected to an electrode of the torch. A positive output is connected to a nozzle, and at a higher positive voltage, to a workpiece. A surge injector circuit of a resistor and surge capacitor is connected in parallel with the power supply to supply current to the arc as soon as breakdown occurs. The duration of the interval between restart pulses is sufficient to allow the surge injector circuit to recharge to a value that will reliably restart the arc as the power supply ramps up to a steady state pilot arc current.