METHOD AND DEVICE FOR CONTROLLING POWER SOURCE FOR SHORT-CIRCUIT TRANSFER WELDING

摘要

PURPOSE:To decrease the generation of a spatter and to perform welding with high quality by detecting the generation of a contraction in a welding wire and decreasing electric current in accordance with said detection. CONSTITUTION:The output signal from a voltage detector 110 which detects the voltage V between a welding torch 104 and a base metal 106 is impressed on a differentiation circuit 113, and the detected voltage V is differentiated with a time (t) by the circuit 113 which outputs dv/dt. The differential value dv/dt is impressed on a comparator 114, which compares the value with the set value set by a setter 115. The comparator 114 impresses the control signal on a welding power source 101 when the differential voltage value increases the set value. A switch 120 is changed over to the setter 121 on the low current side to decrease the output current of the power source 101 hence the current of a welding wire 103. The set value of the setter 115 is determined in accordance with the differential value of the voltage value between the welding wire and the base metal when the welding wire is contracted.