US1717199A

US1717199A - Magnetic core

Info

Publication number: US1717199A
Authority: US
Publication date: 1929-06-11
Anticipated expiration: 1946-06-11

Description

June 11, 1929. J FRANK 1,717,199

MAGNETIC CORE Filed Aug. 23, 1928 I nventor: John J. frank H is Attor'ney.

Patented June 11, 1929.

UNITED STATES JOHN J. FRANK, OF PITTSFIELD, MASSACHUSETTS, ASSIGNOR'TO GENERAL ELECTRIC PATENT. OFFICE."

COMPANY, A CORPORATION OF NEW YORK;

MAGNETIC CORE.

Application filed August 23, 1928. Serial No. 301,592.

My intention relates to magnetic cores for electrical induction apparatus, such as trans formers, and is particularly applicable in connection with very large apparatusot this general character. A well designed'magnetic core is built up of thin superposed layers or laminations of magnetic material which are carefully annealed and insulated from each other to prevent excessive hysteresis and eddy current losses. The layers or laminations, or at least some o'l. them, for very large cores are so wide that .it ditlicult to anneal them properly and to handle them without injury while they are being shaped, during the annealing process and while they are being assembled. The laminations of a large core generally have bolt holes punched in them and are held together by bolts passing through these holes. The bolts interfere with the easy handling of the wide laminations which are apt to be bent and injured as they are assembled over the bolts. The general object of the invention is to provide an improved arrangement of laminations for large cores which may be easily annealed and assembled.

The invention will be better understood from the following description taken in conneetion with the accompanying drawing in which Fig. 1 is a View of a magnetic core having laminations arranged in accordance with the invention and Fig. 2 is a View of three of the wide laminations separated from each other to show details.

Like reference characters indicate similar parts'in both figures of the drawing.

The magnetic core shown in Fig. 1 of the drawing is of a type commonly used in transformers and includes two laminated winding legs 10 connected at their ends by laminated yokes 11. Each winding leg 10 is built up of laminations of different widths, the narrower ones being outside so that the leg approximates a cylindrical. shape to fit inside the windings which surround it in the completed transformer.

The narrower outside laminations 12 may not be too wide to anneal and handle conveniently without danger of injury to them and these are shown in the drawing as being formed in the usual way, each comprising a single magnetic sheet having a row of holes punched in it for the bolts 13. The wider inside laminations 14, however, are each formed in two

longitudinal sections

15 and 16. Each lamination 14 has a central row of bolt holes 17 corresponding in position and spacing to thebolt holes in the narrower outside laminations 12. The joint between the two

sections

15 and 16 of each wide lamination 14 extends along one edge of its row ofbolt holes 17 which are formed as notches in the inner edge of the wider section 15 of the lamina tion. In some of the laminations, the joint between the two

sections

15 and 16 is at one side of the row of bolt holes 17 and in the other lami nations this joint is at the other side ot the bolt holes so that the positions of the wider and narrower sections of some of the laminations are reversed laterally from their positions in the other laminations as indicated in Fig. 2. The inner edges of the wider sections 15 of the laminations thus overlap between the boltholes and are pressed tightly together and held in place by the bolts 13. The narrower sections 16 of the laminations are held tightly in place between the adjacent wvider sections 15 on the same side of the bolts.

It is obvious that by forming each of the wide laminations 14 in two sections, they may ie more easily handled during the shaping and annealing processes and with considerablyless chance of injury to them. This feature also facilitates the handling of the laminations and reduces the chance of injury to them during the assembling operation as they need not be lifted and dropped down around the bolts. In assembling each lamination, its

two sections may be laid upon the part of the 7 core already assembled and pushed together with the edges of the notches or holes 17 surrounding the bolts.

The invention. has been explained by describing and illustrating a particular form thereof, but it will. be apparent that various changes may be made without departing from thescope of. the invention as defined.

What I claim as new and desire to secure by Letters Patent ot the United States, is:

1. A magnetic core including superposed laminations, each of said laminations including two longitudinal sections, and the inner edge of at least one of said sections having notches therein to provide bolt holes.

2. A magnetic core including superposed laminat-ions, each lamination including two longitudinal sections of unequal widths, and the inner edge of at least one of the sections of each lamination having notches therein to provide bolt holes.

3. A magnetic core including superposed laminations, each of said laminations including two longitudinal sections, the inner edge of at least one of the sections of each lamination having notches therein to provide bolt holes, and the width of one of the sections of each lamination being greater than that of the other section by an amount substantially equal to the distance across one of said bolt holes.

4. A magnetic core including superposed laminations, each of said lan'linatio-ns including two longitudinal sections, the inner edge of at least one of the sections of each lamination having notches therein to provide bolt holes, and some of said lamination sections at opposite sides of said bolt holes having their inner edges overlapped.

5. A magnetic core including superposed laminations, provided with a row of bolt holes, each of said laminatious including two sections separated by a joint near an edge of said row of bolt holes. I

6. A magnetic core lamination including two longitudinal sections, there being notches along the joint between said sections to provide bolt holes.

In witness whereof, I have hereunto set my hand this 21st day of August, 1928.

JOHN J. FRANK.