GB745534A - Improvements in and relating to three-phase electric transformers and to laminated magnetic cores therefor - Google Patents

Abstract

745,534. Transformers. ENGLISH ELECTRIC CO., Ltd. Feb. 12, 1954 [Feb. 18, 1953], No. 4515/53. Class 38 (2). A laminated magnetic core comprises three winding limbs and two flux return paths, each of the three winding limbs having a cooling duct therethrough which extends throughout its length and across it at right angles to the plane of the laminµ. Each limb is formed by two sets of laminae such as 1a, 2a, which are arranged in a parallel relationship but which are staggered lengthwise by a distance equal to the width of the yoke 7c 'or 9c and which are arranged to have a space between them to form the cooling duct. To achieve full interleaving of the limb laminµ with the yoke laminµ, further groups of laminµ are provided as illustrated in Fig. 1B, wherein the butt joints between the respective laminµ occur at different positions to the corresponding joints of the group shown in Fig. 1A so that when the two groups are assembled the joints in the group according to Fig. 1B occupy the dotted positions shown in Fig. 1A. In another embodiment the ends of the laminµ may be cut at an angle to take advantage of laminar material which has a preferred magnetic direction. The Provisional Specification describes a singlephase magnetic core having one only winding limb and two flux-return paths.