GB707673A - Improvements relating to the construction of laminated magnetic cores - Google Patents

Abstract

707,673. Transformers and inductors. METROPOLITAN-VICKERS ELECTRICAL CO., Ltd. Nov. 20, 1951 [Nov. 24, 1950], No. 27216/51. Class 38 (2) Separate magnetic laminar inserts having their grain orientated substantially in the mean direction of the natural flux path form the corner joints of a magnetic core of grain orientated magnetic steel laminations whereby to reduce noise and losses which would otherwise result from the flux travelling transversely to the grain at such corners. As shown, in diagonally opposite comers of the top layer of the core, leg and yoke laminations 1, 3 and 2, 4 are joined by inserts 5 in each of which the grain it at 45 degrees to both abutting leg and yoke laminations, while the remaining joints are mitred. The joint pattern is reversed in each adjacent layer. The outside corner of each insert, where little flux travels, is cut off to leave a bevelled edge 6. In modifications, the mating edge 8, 9 between each insert and either a leg or yoke lamination may have saw-tooth serrations, which may be resistance welded as described in Specification 295,281, [Class 83 (iv)]. In this case all corner joints would have inserts, and the saw-tooth joints would be staggered in adjacent layers. The insert may alternatively be triangularshaped, the edge 6 extending between the mating edges of the insert ; or the joint between the insert and either the leg or yoke lamination may be other than perpendicular to the longitudinal edge of such lamination.