ELECTRIC ARC WELDING APPARATUS

摘要

A welding wire feeder system for an electric arc welder in which the wire feed motor M is powered from a pulse width modulated power supply comprising a power transistor Q10 controlled by a pulse signal on line 31 from a pulse width modulator comprising an integrated circuit A3. A control voltage proportional to the arc voltage and a feedback voltage indicative of the feed motor speed are generated and applied to respective inputs of a high gain amplifier A4-1 whose output error signal is either high or low dependent upon the relative values of the control and feedback signals. Control is effected in such a manner that an increase in welding arc voltage causes a corresponding increase in the welding wire feed rate, and vice versa.