METHOD FOR CONTACTLESSLY STRIKING AN ARC AND WELDING CURRENT SOURCE FOR CARRYING OUT A STRIKING PROCESS

• Main Authors: PRINZ, Andreas, MUSIL, Franz Peter
• Format: Patent
• Language: English; French; German
• Published: 29.07.2020
• Subjects: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC,OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWERSUPPLY SYSTEMS; CLADDING OR PLATING BY SOLDERING OR WELDING; CONTROL OR REGULATION THEREOF; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUTPOWER; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER; CUTTING BY APPLYING HEAT LOCALLY, e.g. FLAME CUTTING; ELECTRICITY; GENERATION; MACHINE TOOLS; METAL-WORKING NOT OTHERWISE PROVIDED FOR; PERFORMING OPERATIONS; SOLDERING OR UNSOLDERING; TRANSPORTING; WELDING; WORKING BY LASER BEAM

The invention relates to a method for contactless ignition an arc (L) between an electrode (3) and a workpiece (4) which is to be welded, for carrying out a welding process, wherein a welding current (I) and a welding voltage (U) are provided at an output (2) of a welding current source (1), wherein the welding current source (1) contains a resonance converter (5) for generating a periodically varying, preferably substantially sawtooth-shaped, open circuit welding voltage (ULL) with voltage maxima (ULL,max) which recur periodically with a repetition rate (fw) and a welding current source (1) for carrying out the igniting process. In order to achieve reliable contactless ignition of the arc (L) without complicated circuitry, the resonance converter (5) is formed by a series-parallel resonant converter, and temporally synchronous high-frequency pulses (UI,HF) are superimposed on the open circuit welding voltage (ULL) in the region of at least some of the periodically recurring voltage maxima (ULL,max) of the open circuit welding voltage (ULL).