Parts-in-place safety reset circuit and method for contact start plasma-arc torch
US6350960B1 · kind B1 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 28, 2000 |
| Grant date | Feb 26, 2002 |
| Priority date | — |
| Expiry date | Nov 28, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH05H1/3489
- WIPO fieldChemical engineering
- WIPO sectorChemistry
Abstract
A contact plasma-arc torch having a parts-in-place safety reset circuit and method. The torch includes an electrode and a tip. A safety reset circuit monitors parameters associated with the electrical relationship between the electrode and the tip to determine whether the tip and/or electrode are properly installed. The circuit also monitors an electrical relationship associated with the workpiece to detect when current is flowing in the workpiece when such current is not expected. The torch power supply and associated circuitry includes a soft start capability whereby the full power output of the power supply is supplied to the electrode over time due to the soft start characteristic of a soft start circuit. If the safety reset circuit detects that the tip and/or electrode arc not properly installed, or that current is flowing in the workpiece when such current is not expected, the safety reset circuit resets the soft start circuit. When the soft start circuit is reset, the power applied to the electrode is returned to its initial starting value at or near zero volts. Thus, full power output is not applied to the electrode when the tip and/or electrode are not properly installed.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.