Method of and structure for high speed resistance seam welding

A method of high speed resistance seam welding comprising connecting an auxiliary transformer having three primary windings to a three phase source of electrical welding energy, providing a seam welder welding current transformer having a primary winding and a secondary winding between the auxiliary transformer and high speed resistance seam welding structure, connecting the primary winding of the seam welder transformer in parallel with one of the auxiliary transformer primary windings and connecting the secondary winding of the seam welder transformer to the seam welder structure and phase controlling the welding energy provided to the primary winding of the auxiliary transformer from the three phase source of welding energy.

Structure for energizing high speed resistance seam welding structure comprising an auxiliary transformer having three primary windings adapted to be connected to separate phases of three phase electrical welding energy, phase control structure in each auxiliary transformer primary winding and means for energizing the high speed resistance seam welder structure from the auxiliary transformer comprising a seam welder current transformer having a primary and secondary winding, means connecting the primary winding of the seam welder current transformer to one of the primary phase windings of the auxiliary transformer and means for connecting the secondary winding of the seam welder current transformer to the seam welder structure.

High speed resistance seam welding structure ecomprising a source of three phase electrical energy, an auxiliary transformer having three separate primary windings, means connecting each of the auxiliary transformer primary windings across a separate phase of the three phase source of electrical energy, a single auxiliary transformer secondary winding, a seam welder current transformer having a primary winding connected in parallel with the secondary winding of the auxiliary transformer and having a secondary winding connected directly to the seam welder structure and separate phase control means in each auxiliary transformer primary winding for controlling the energizing of the associated transformer primary winding from an associated phase of the three phase source of welding energy to energize each primary winding of the auxiliary transformer at a different time and with only one phase of the primary winding being energized at any time for a full cycle and providing a predetermined time delay between energizing of the separate auxiliary transformer primary windings for a time equal to one of 120.degree. and 240.degree. of a single cycle of the three phase source of electrical energy.

High speed resistance seam welding structure comprising a source of three phase electrical energy, an auxiliary transformer having three separate primary windings, means connecting each of the auxiliary transformer primary windings across a separate phase of the three phase source of electrical energy, a seam welder current transformer having a primary winding connected across one of the primary windings of the auxiliary transformer and having a second winding connected directly to the seam welder structure and separate phase control means in each auxiliary transformer primary winding for controlling the energizing of the associated transformer primary winding from an associated phase of the three phase source of welding energy to energize each primary winding of the auxiliary transformer at a different time and with only one phase of the primary winding being energized at any time for a full cycle and providing a predetermined time delay between energizing of the separate auxiliary transformer primary windings for a time equal to one of 120.degree. and 240.degree. of a single cycle of the three phase source of electrical energy.

High speed resistance seam welding structure comprising a source of three phase electrical energy, an auxiliary transformer having three separate primary windings, means connecting each of the auxiliary transformer primary windings across a separate phase of the three phase source of electrical energy, a single auxiliary transformer secondary winding connected directly to the seam welder structure and separate phase control means in each auxiliary transformer primary winding for controlling the energizing of the associated transformer primary winding from an associated phase of the three phase source of welding energy to energize each primary winding of the auxiliary transformer at a different time and with only one phase of the primary winding being energized at any time for a full cycle and providing a predetermined time delay between energizing of the separate auxiliary transformer primary windings for a time equal to one of 120.degree. and 240.degree. of a single cycle of the three phase source of electrical energy.

In combination, a source of three phase electrical energy, high speed seam welding structure, a transformer with three primary windings connected to the three phases of the three phase source of electrical energy, means for energizing the seam welding structure from the transformer and means operably associated with the transformer for alternatively energizing one transformer primary winding at a time with a full cycle of one phase of the three phase source of electrical energy at a time and providing a time delay equal to one of 120.degree. and 240.degree. of the electrical energy in the three phase source of electrical energy between energizing of the separate primary windings of the transformer.