Method of making transformers and cores for transformers

Abstract

A method of making a transformer having a core composed of a web of magnetic amorphous metal of small thickness. The laminations of the core of the transformer are the stacked turns formed by winding the web into a spiral having a window in the center. The coils are wound as integral structures having openings for telescoping the coils onto the core. For the telescoping, the core is cut and converted into a U-shaped structure on whose arms the coils are telescoped. The cut joint is a butt-lap-step joint. To produce such a joint, the laminations are divided into groups and each group is divided into steps which are spaced longitudinally of the web. After the coils are telescoped onto the core, the cut ends of the arms of the U are abutted to form a closed core. The cuts in the laminations that make up alternate groups in the stack are inclined to the longitudinal center line of the web at a first angle different from 90.degree.. The cuts in the laminations that make up intervening groups in the stack are inclined oppositely to the cuts in the alternate groups at an angle which is also different from 90.degree.. Because of the different inclination of successive cuts, the undesired abutting of laminations from different groups during the reclosing of the core is precluded. There is also disclosed a core and a transformer made by the method.