Method of and apparatus for assembling a transformer core

Abstract

A method of assembling a transformer core in which a lamination of rectangular plates formed of a magnetic material is inserted in the spaces in primary and secondary transformer coils, and in which the opposite ends of the lamination are brought into abutment each other to form the lamination into an annular shape. The lamination of the magnetic material plates is bent into a U-like shape with the transformer coils thereon and is magnetized by energizing the transformer coils, while the opposite ends of each magnetic material plate are restrained from being brought closer to each other. The opposite ends of the laminated magnetic material plates are successively released from the restrained state from the innermost opposed ends of the U-like shape to attract and closely contact each other by the magnetic force. The method is carried out with an apparatus having a flat plate on which the lamination of magnetic material plates is placed, a pair of guide plates having parallel vertical surfaces and used to support the magnetic material plates so that the plates are maintained in the state of being bent in the U-like shpae, a pair of pressing members for restraining the opposite end portions of each magnetic material plate from being brought closer to each other, a driver for moving the pair of pressing members step by step toward the open end of the U-like shape; and a device for magnetizing the end portions of the U-shaped magnetic material plates by energizing the transformer coils.