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..

Abstract: A method of making a product for use in fabricating a low-loss core of a transformer. The core is composed of a web of amorphous metal of small thickness. In forming the product, the web is wound into an annular spiral structure on a circularly cylindrical mandrel. The structure is removed from the mandrel and collapsed into an approximate figure "8" shape and groups of cuts are produced in the upper collapsed surface of the figure "8". Each cut defines a step of a group. Each step has a number of turns of the web and each group has a number of steps. The steps of each group are offset in a succession along the structure and penetrates progressively into the structure. Successive groups extend progressively inwardly throughout the structure. The cuts subdivide the structure into separate strips. The strips are wrapped in a spiral to form a lapped spiral structure onto a second circularly cylindrical mandrel of smaller diameter than the first mandrel.

Abstract: A transformer having a core having a butt-lap-step joint. The laminations of the core are the turns of a spiral into which a web of very thin amorphous magnetic material is wound. At the joint, the core is cut producing opposite folds whose ends are aligned. The purpose of the joint is to enable the core to be opened by pealing off the folds defining the cuts and converted into a U-shaped structure; coils are telescoped on the arms. The core is closed by refolding the folds and aligning the ends of the opposite folds. At the joint the laminations, subdivided into successive groups, are cut at an angle of the order of 87.degree. to the center line of the laminations; alternate groups being cut inclined in one direction and the intervening groups being cut inclined oppositely. The oppositely inclined cuts preclude mismatching and mislocating the groups when the core structure is closed after the coils are telescoped on the arms.

Abstract: Disclosed is a method of preparing an amorphous metal core 1 for use in a transformer. The uncut legs 7, 8 and 9 of the core 1 are covered with an adhesive impregnated substrate 10, the edges 11 of which are bent over to make contact with the core 1. A release sheet 12 and a plate 13 are placed over the adhesive impregnated substrate, the plate 13 is pressed against the core 1, and the adhesive is cured. The process is repeated with the edges on the opposite side of the core.