DIRECT CURRENT ARC WELDER

摘要

In a direct current arc welder comprising a phase control circuit for controlling the triggering phase of at least one controlled rectifier element to convert alternating current into direct current which is in turn supplied to a welding electrode and a workpiece to be welded and a feedback circuit for negative-feeding a portion of the direct current thus converted back to the phase control circuit thereby to control the welder output, a gain compensating circuit for compensating the gain of a control circuit in response to the value of said direct current output of the welder to maintain said gain at a substantially constant value no matter what level the value of said direct current output may be.