| 摘要 |
<p>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 tendsto 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.</p> |
