Abstract: A transformer for application in portable resistance welding machines assembled from toroidal sections of iron core, primary and secondary windings arranged concentrically one with another. The primary is constructed from copper plate modules so as to form a continuous single layer winding of toroidal form in which the separate modules are electron-beam welded one to another in order to form the continuous primary winding. A single turn secondary completely encloses the primary winding and iron core so as to form a compact cylindrical electrical transformer structure. A liquid electrical insulating material is sealed within narrow gaps between iron core, primary winding and secondary winding to allow good thermal transfer from these elements to a cooling medium and at the same time stabilize the relative position of these elements against the dynamic forces developed by the high currents passing through the secondary.

Abstract: Portable direct current resistance welding apparatus incorporating a flexible cable assembly comprising a pair of flexible conductors maintained at a fixed distance from one another with restraining means which prevent the separate cables from moving one with respect to the other. A flexible sleeve holds the conductors in parallel relationship to one another at a distance of at least four inches by means of a multiplicity of separating and restraining means fastened to the sleeve at intervals along its length while retaining full flexibility in the cable assembly.

Abstract: A method and apparatus for monitoring parameters which control the quality of welds made by the rotating arc method. Total electrical energy delivered to the parts being welded is controlled and its analog divided by the time during which this energy was applied to obtain average rate of energy delivered. Total mechanical work done on parts being welded and the mechanical relative displacement of machine platens is measured and work analog is divided electronically by the displacement analog to determine average mechanical work per unit of displacement. The two averages thus obtained are compared to preset levels of average electrical energy and mechanical work which have been established empirically. Indicators warn the operator of any variation from the norm. Separate indications and comparisons are also made of each of the parameters.

Abstract: Apparatus for welding parts, such as pipes, end to end by means of an electric arc which is caused to rotate along the adjacent edges of the pipes. Two separate magnetic fields are used to cause the arc to follow a spiral path along the edges so that pipes having a wall thickness greater than one quarter of an inch may be welded.