GB718873A - Improvements in core joints for electro magnetic induction apparatus - Google Patents

Abstract

718.873. Transformers and inductances. GENERAL ELECTRIC CO. Jan. 7, 1953 [Jan. 9, 1952], No. 507/53. Class 38(2) A magnetic core comprises packs of laminations forming its leg and yoke members which join at mitred corners, at least one of the leg members comprising several packs of laminations of different lengths having mutually offset mitred joints, the joints of all the legs being tapered and the tapering of adjacent Iaminations in each pack differing in such a manner that the mitred joints of adjacent layers converge from the outer to the inner edge of the core to form a tapered overlap. Leg members 2, 4 are similar and comprise packs of laminations 8 . . . 12 which vary in width and length, the adjacent laminations forming mitre joints with the corresponding laminations in the yoke parts 6, 7 along the lines 13, 15 which two joint lines converge from the outer to the inner edge of the core. All the laminations of these corners meet at one or other of these lines. The centre leg 3 is also formed from packs of laminations which vary in width and length, but in this case more than two joint lines exist, all the laminations in the outer packs, i.e. 8, 12 meeting the corresponding yoke laminations on either of the joint lines 14, 16, the laminations of packs 9, 11 meeting on joint lines 17 or 18, whilst laminations in pack 10 meet along joint lines 19 or 20. Each leg member has a plate 22 fixed on either side of it and spaced therefrom by a layer 23 of insulation, and each plate has a stud 24 secured thereto. Clamp members 25 are fixed to the yoke sections 6, 7 and have cross bars 30 associated therewith through which pass the studs 24. After the leg and yoke members have been drawn together by means of studs 24, bolts 29 are screwed through the clamp members 25 into lugs 27 affixed to plates 22, thus retaining the core in its assembled position. One method of constructing such a transformer is to build up the core layer by layer flat on a floor, then uprighting the core, removing the upper yoke member by means of the assembly 22, 24, 25, 30, assemble the windings on the leg members and replacing the upper yoke member.