GB1027706A - Magnetic core structure for inductive apparatus - Google Patents

Abstract

1,027,706. Transformer cores. WESTING- HOUSE ELECTRIC CORPORATION. Sept. 7, 1964 [Oct.10, 1963], No. 36538/64. Heading H1T. The four major sides 61, 63, 65 and 67 of a wound laminated core are joined by corner portions 69, 71, 73 and 75, at least the outer periphery of each corner forming at least one straight line joined by bends to the major sides in order that the core will maintain its shape during use. The joints are openable to allow the insertion of coils. The core is constructed by winding a plurality of turns of strip magnetic. material around each other to form a circular structure which is then cut along a radial line to enable the structure to be uncurled, Fig. 16 (not shown). A clamp 161 is then applied and the straight portions 157 are curled around so that their ends abut against the stapped portions 159 forming a circular structure with a desired pattern of stepped lap joints, Alternatively, the circular core is constructed by cutting the individual laminations into suitable lengths, whereby on curling up they form a circular structure with the desired step-lap joints (Fig. 2, not shown). The resulting circular structure is die-pressed into the shape, Fig. 6 (not shown), and then annealed after which it takes the shape shown in Fig. 5. A spreader 82, Fig. 7 (not shown), is placed in the window 70 during annealing to take up stress. If the ends of the laminations form wedge shapes and the joints are formed over the lines 92, 94, Fig. 10 (not shown), the core becomes self-locking and no core band is required. The core may also be built up from individual packets of die-pressed laminations which are then assembled over each other, Fig. 12 (not shown).