Miller Electric Manufacturing Company

Robet L Risberg

A constant potential single phase A.C. power welding source is connected to a thyristor network and an energy storing inductor to create a square wave welding current that is adjustable in height, and is further adjustable to allow either half-cycle to be wider than the other, the sum of two adjacent half-cycles always equaling 360.degree.. The welding current is forced to reverse rapidly by a substantial voltage to insure conduction when the welding load is an arc to an aluminum work piece, and the aluminum tends to rectify. The heights of the positive and negative half-cycles are simultaneously adjustable in response to manual control and feedback signals. In addition, the ratio of the heights of the positive and negative half-cycles can be other than 1:1 by selectively enabling a conduction path through a different number of turns on the inductor during the negative and positive half-cycles, such enabling being either continuous or on an adaptive feedback basis as a function of arc length as determined by arc voltage. The height difference is effective in a step fashion since the total ampere-turns must remain constant. The thyristor network may also be re-connected for full-wave rectification for D.C. welding.

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Brookfield, WI, United States of America

Robet L Risberg