Abstract: A magnet wire having differential build insulation for use in transformer coils is disclosed. The wire has a rectangular conductor with an insulation that is thicker on the top and bottom surfaces of the wire than it is on the sides. With the thicker coating on the top and bottom, the wire can be used in layer wound distribution transformer coils, both high voltage wire wound coils and low voltage wound coils, without needing additional insulation between the layers of the winding.

Abstract: A method and apparatus for manufacturing a variable insulated helically wound electrical coil is disclosed. Insulated rectangular wire is fed from a supply reel to a coating zone and within the coating zone liquid resin insulation is selectively applied to the wire so it has additional insulation only in those areas of the coil where the dielectric strength is needed. The insulated wire is fed through a curing station to allow curing of the additional insulation prior to winding the cured insulated wire into a coil. The cured insulated wire is wound into a coil of predetermined shape at a winding station whereby the portions of the wire having the additional insulatin are located in the areas of the coil where the greatest dielectric strength is needed. The timing of the resin application to the wire is coordinated with the winding of the coil so that the proper insulation thicknesses are achieved at the required locations in the coil.

Abstract: An insulated metallic strip suitable for use in the coils of power transformers and method of producing the same. Following the extrusion of a flat metallic strip of conductive material for winding into a magnet coil, the flat strip having a predetermined thickness and first and second sides bounded by a pair of fully rounded edges, the method of insulating the strip of conductive material by supporting the flat strip in a level state at a predetermined temperature in a vacuum chamber and while in the vacuum chamber applying a liquid coating of resin to the entire first side of the strip and the pair of rounded edges and extending onto the second side of the strip from each of the edges a distance at least as great as about 0.25" to prevent turn to turn discharge.

Abstract: A method and apparatus are disclosed for minimizing the distortion in cold pressure welding and producing a spot lap weld with a controlled thickness. A distortion control device is utilized which includes a cavity of predetermined depth and area adequate to receive the metal flow resulting from the spot lap weld to be formed.

Abstract: An insulated metallic strip suitable for use in the coils of power transformers and method of producing the same. Following the extrusion of a flat metallic strip of conductive material for winding into a magnet coil, the flat strip having a predetermined thickness and first and second sides bounded by a pair of fully rounded edges, the method of insulating the strip of conductive material by supporting the flat strip in a level state at a predetermined temperature in a vacuum chamber and while in the vacuum chamber applying a liquid coating of resin to the entire first side of the strip and the pair of rounded edges and extending onto the second side of the strip from each of the edges a distance at least as great as about 0.25" to prevent turn to turn discharge.

Abstract: Coil-core assembly for a transformer including a plurality of coils and cores supported in a U-frame. The frame includes a cross member from whose ends legs extend. The cross member and the legs are channels. Near the corners of the frame the flanges of the channels are separated so that the legs are, in effect, hinged about the material remaining at the corners. Before the coils and cores are inserted in the frame, the legs are set at an angle of between 91.degree. and 93.degree. to the cross member so that the coils and cores may be readily positioned in the frame. On each side of each gap, spanning the gap, axially coextensive lugs are welded to the flanges. The coils and cores are disposed on the cross member between the legs.