GB1015693A - An arc welder - Google Patents

Abstract

1,015,693. Welding by fusion. PULSE ARC WELDER CO. April 30, 1963 [May 7, 1962; Feb. 25, 1963], No. 17006/63. Heading B3R. [Also in Division H2] A stored energy discharge welding circuit comprises banks of capacitors 63-70, charged through a rectifier 32, resistor 34 and contacts 38, 41 discharging into two circuits. One 96- 98 forms a resonant circuit of high-frequency, say 1000 Me., which initiates a discharge across the electrodes 14, 16, and the second reduces the impulse through an autotransformer 90 to a value high enough to maintain the arc, but not to strike it. In the event of an arc not being struck the capacitors are discharged through the autotransformer winding 90 to earth. Should the operator touch the electrodes 14, 16, the resonant circuit 96, 98 is thrown out of resonance thus reducing the H.F. voltage. The transformer 78 core which may be of ferrite saturates at a value which prevents the energy discharging through the second circuit from being transformed back into the first circuit. A small capacitor 104 of low inductance is paralleled with the main capacitors 63-70. The H.F. pulse is diverted from the rest of the circuit by a low current rapid switching diode 110 in parallel with a high current diode 112. Either or both of the electrodes 14, 16 may be a workpiece, e.g. a wire or a bundle of wires.