Method of restarting a plasma arc torch using a periodic high frequency-high voltage signal
US5296665A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | May 19, 1992 |
| Grant date | Mar 22, 1994 |
| Priority date | — |
| Expiry date | May 19, 2012 |
Classification
- Technology area (CPC B)Performing Operations; Transporting
- CPC primaryB23K10/006
- WIPO fieldMachine tools
- WIPO sectorMechanical engineering
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.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.