GB918663A - Improvements in and relating to laminated electromagnetic cores - Google Patents

Abstract

918,663. Inductors. GENERAL ELECTRIC CO. Ltd. Feb. 22, 1961 [March 24, 1960], No. 10486/60. Class 38 (2). A laminated electromagnetic core construction, e.g. for a choke or combined choke and transformer unit comprises a easing 1 (Figs. 1, 2) enclosing a choke coil carried on core limb 2 so that the flux path through the core is longitudinally through the core limb 2 then longitudinally through the casing 1 back to the core limb 2. The casing part 4 is formed from two packs of U-shaped strip laminations 5 which fit one within the other and are held together by tubular rivets 6, 7 which also serve as grommets for coil leads. A strengthening channel 8 is formed by indenting the part 4. Lamination packs 3 and part 4 are dipped in varnish, then packs 3 are sprung into the open sides of part 4 and are thus self-retaining. A V-shaped nick is formed where packs 3 meet so as to restrict the eddy current path through the core. Core limb 2 which may be in a number of sections projects through a rectangular hole 10 at one end of the part 4 to permit adjustment of the air gap(s). The laminations of the projecting portions of the core limb 2 may be formed integrally with the transformer laminations. Alternatively packs 5 may fit together differently or may be formed by bending a single pack of strip laminations in a closed loop (Fig. 3, not shown).