Abstract: A transformer core includes a first core member formed by laminating grain oriented 3% silicon steel sheets and second core members disposed at respective sides of the first core member in the direction of lamination so that the first core member is sandwiched by the second core members. Each second core member is formed by laminating non-oriented 6.5% silicon steel sheets. A commercial frequency component of magnetic fluxes mainly passes through the second core members such that an amount of noise caused by a higher harmonic component is reduced.

Abstract: A method for fitting magnetic wedges which comprises steps of passing a current through a stator winding on a stator core of an electric rotary machine to produce magnetic flux passing through slot openings, successively forcing the magnetic wedges in the slot openings while keeping the winding energized to maintain the magnetic wedges in predetermined positions in the slot openings, and impregnating varnish into the stator core with the slot openings fitted with the magnetic wedges and with the stator winding kept energized, and an apparatus for embodying the method.