Twin pulsed arc welding system

摘要

The invention provides a gas-shielded arc welding system using two side-by-side electrodes each of which is provided with current pulses superimposed on a respective background current level to maintain the desired controlled spray transfer mode of the weld metal without overheating effects. The pulses are supplied to the two arcs out of phase with one another to minimize interaction of their magnetic fields, but this alone is not sufficient to assure stability of the two arcs. In the system of the invention, one arc is designated as the master arc and the other as the slave arc. The master arc is stabilized by means of a feedback loop controlling its master pulse frequency. Each master pulse triggers a respective slave pulse after a preset time delay, in this way keeping corresponding master and slave pulses in synchronism. This is not necessarily sufficient to stabilize the slave arc and independent stabilization is therefore provided for it by a feedback loop controlling its pulse duration or its background current, but preferably by controlling both simultaneously.