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:
Apr. 15, 1997
Filed:
Oct. 30, 1995
Dennis M Borowy, Hanover, NH (US);
Jeffrey L Peterson, Lebanon, NH (US);
Hypertherm, Inc., Hanover, NH (US);
Abstract
An arc control circuit in a plasma arc torch, having an electrode and a nozzle, maintains a plasma arc during operation of the torch. The circuit includes a power supply electrically coupled to the electrode, nozzle and a workpiece. A logic device opens a power switch electrically coupling the nozzle to the power supply, disconnecting the nozzle from the supply, when a transferred arc is formed between the electrode and the workpiece. An amplifier is electrically connected to the power supply. The amplifier compares a sensed current to an operating current. The amplifier increases the output voltage of a power supply to maintain the operating current in coordination with an increasing distance between the workpiece and the torch. A comparator is electrically connected to a logic device and compares the output voltage of the power supply to a maximum voltage. When the output voltage of the power supply exceeds the maximum voltage, the comparator sets the logic device. The logic device generates an output signal to close the power switch and reconnect the nozzle to the power supply, thereby initiating switching of the arc from the workpiece to the nozzle.