JPS55149778A - Consumable electrode arc welding electric power unit - Google Patents

Abstract

PURPOSE: To achieve the improvement of weldability and make the controlling of welding arc perfect by adding a control signal generating circuit, etc. to the welding electric power source and performing the output controlling at the short-circuiting in an electronic circuit manner.

CONSTITUTION: A short arc recognition circuit (o) identifies whether the electric power source load (d) is arc or short circuit. This signals causes a conduction- angle-at-the-short-circuit-control circuit (j) and a conduction-angle-at-the-arc-control circuit (n) to actuate. The outputs of a reference-conduction-angle setting circuit (condition setter) (m) as well as the conduction-angle-at-the-short-circuit control circuit (j) and conduction-angle-at-the-arc control circuit (n) are synthesized in a synthesizing circuit (g) in the direction shown by the conduction angle of a control rectifying element. Receiving this signal, a control-rectifying-element-control circuit (f) generates the control signal to provide the specified conduction angle in correspondence to the short-circuit time or arc time between gate and cathode. Circuits of changing the conduction angles are specified are provided to both conduction-angle control circuits respectively, so that their control signals are generated at the output ends of the respective mixing circuits Mx₁, Mx₂.

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