ELECTROMAGNETIC DEVICE AND ITS MANUFACTURING METHOD

PROBLEM TO BE SOLVED: To reduce the projected section distributing magnetic flux thereby decreasing the loss for cutting down the welding manhours by laminating electromagnetic steel sheets to provide iron cores fixed by projection-welding step and a coil around the iron cores. SOLUTION: Electromagnetic steel sheets 7 are laminated to be projection- welded for the formation of the first iron core 1. In order to form the first iron core 1, the electromagnetic steel sheets 7 laminated making use of the protrusions 8 are projection-welded by resistance welder having an upper and lower electrodes and an alignment frame to produce a welded body 6 connecting the whole laminated electromagnetic steel sheets 7. At this time, to cut down the loss in welding manhours, one columnar welded body 6 as a fixing means is formed by the projection welding in one position passing through two each of the first iron cores 1 in the direction of laminated respective electromagnetic steel sheets 7 to avoid one turn shortcircuit path. Furthermore, in view of the economy and production, the manhours can be cut down more efficiently by the projection-welding step than the TIG welding step successively welding the whole length.