US2705781A - Transformer coil support held by crimped frame - Google Patents

Description

April 5, 1955 J. M. ANDERSO N TAL 2,705,781

TRANSFORMER COIL SUPPORT HELD BY CRIMFED FRAME mvm United States Patent() TRANSFORMER COIL SUPPORT HELD BY CRIMPED FRAME John M. Anderson, Jack E. Croker, and Walter U. Glishke, Pittsburgh, Pa., assgnors to Allis-Chalmers Manufacturing Company, Milwaukee, Wis.

Application March 8, 1952, Serial No. 275,636

1 Claim. (Cl. 336-208) This invention relates generally to electrical induction apparatus and in particular to supports for the coils of such apparatus.

The electromagnetic characteristics of transformers and reactors which embody improved, oriented electrical steel are affected adversely Iif that steel bears the Weight of the coils of the apparatus. Even slight deformation of that steel from its annealed shape will result in strains that affect the core losses and permeability of the steel. Slight displacements of the laminations of the steel core may negate the advantages paid for in the premium steel. These disadvantages are particularly noticeable in the wound core constructions in which the electrical coillrests upon the at surface of the laminations of the stee The above mentioned disadvantages are avoided in accordance with this invention by a coil support provided for such apparatus, which is combined with portions of the core fratne in a manner such that the coil is firmly supported substantially Iindependently of the core.

It 'is an object of this invention to provide a support for coils of transformers and reactors which is com bined with the core frame of the apparatus so as to be simply manufactured and assembled and securely retained in its position without the coil or its support imposing any noticeable strain on the core of the apparatus.

Another object of this invention -is to intertit a portion of the core frame and the coil support to prevent movement of the coil support.

Still another object of this invention is to provide a coil support for transformers or reactors by which the weight of the coil is borne by the core frame through the coil support without straining the stel laminations in the core and with the coil support made to cooperate with the coil and the core frame so that it may be quickly and easily inserted in place even after the coils are assembled about the winding legs of the core.

These and other advantages will become apparentto those skilled in the art to which this invention relates from the following description, when read in connection with the accompanying drawings, in which:

Fig. 1 is a cross section of a part of a tank containing a transformer shown partly in elevation and partly in sect-ion;

Fig. 2 is a side view partly in section of the transformer and tank shown n Fig. l; and

Fig. 3 is an isometric view of the coil support and part of the core frame illustrated in Fig. 1.

A transformer 11 is contained in a casing 13 filled with oil or other insulating and cooling fluid 12. The transformer has a single magnetic circuit comprising a core of magnetic material, such as cold rolled electrical steel wound in a generally rectangular shape. The core has two straight winding legs 16, 17 and two yokes 18, 19. Each core leg has a coil surrounding it. Coil 21 is around leg 16, and coil 22 is around leg 17. These coils are of conventional construction with a cylindrical insulating barrier 23 between the winding leg of the core and the inner portion 24 of the coil. Additional cylindrical insulating barriers 26 surround that inner coil portion 24, separating it radially from an outer coil portion 27. Spacers (not shown) are inserted between the barriers 26 and between barriers and coil portions to define cylindrical passageways 28 extending axially through the coil for circulation of the cooling tiuid.

The core is held in a frame which has side pieces 34, 35 clamped against opposite edges of the lamnations ice of the upper yoke 18. The side pieces may be separate but are preferably integral with a web 36 to form a channel clamped against the outer lamination of the upper yoke. Since that channel is preferably made of metal, insulation 41 is inserted between the side pieces and the yoke 18. Another core frame channel is similarly associated with the lower yoke 19 with insulation 42 between the core steel and the side pieces 37, 38 of web 39 of the channel. These two channels are held together by sheet metal connecting members 43, 44, which extend parallel to each other along the outer sides of the legs 16, 17 of the core. The ends of each of these connecting members have tangs which extend through openings in the channels and which are bent over against the outer surfaces of I the webs of the channels to thereby hold the core frame together. Numeral 46 identities the tangs at the upper end of connecting member 44.

The channels have fend portions which extend beyond the corners of the core, and coil supports are placed between those extending portions and the coils 21, 22. These supports may extend for a considerable length abutting against the bottom surface of the coil. By thus supporting the coil these supports relieve the core lamina tions of the weight of the coil. However, these coil supports must not impede the free passage of cooling uid through the passageways in the coil.

In the illustrated embodiment, a support 51, which may be of sheet metal but is preferably of suitable insulating material such as wood, is placed at the bottom of coil 22. The upper portion of the support has a raised surface abutted against the bottom edge of the coil and has a recessed surface spaced from the bottom of the coil to thereby perm-it cooling liquid to flow to the coil. In the illustrated embodiment the abutting raised surface 54 is divided into several parts by grooves or channel cuts extending across the support, and the bases of these grooves are the recessed surface 55.

The support is restrained from moving crosswise of the side pieces 37, 38 by longitudinally spaced surfaces of the support 51 which abut against the side pieces 37, 38. In this Iinstance the lower portion of support 51 has two narrow parallel grooves which extend crosswise of the support. The distance between these longitudinally spaced grooves corresponds to the distance between the side pieces 37 and 38, and edge portions of those side pieces snugly iit into those narrow grooves, abutting against the sides of the grooves.

The support 51 is also restrained from moving in directions lengthwise of the side pieces 37, 38. This is done by forming a kink at any suitable location in the edge of at least one of the side pieces. Preferably, the end tips 63, 64 of those side pieces are crimped so that they bind in the grooves at the outer side of support 5l and thereby rmly hold the support against the core frame connecting member 44.

The upper portion of support 51 is preferably made longer than the distance between the core frame side pieces so as to provide adequate suspension of the coil.

The other coil, 21, has a support 66 which is similar to support 51 and interiits similarly with the extending portion at the opposite end of the lower channel.

At the top of the coils 21, 22 there are provided spacing members 71, '72, respectively. These may be blocks of insulating material, such as wood, which are held by suitable means between the web 36 and the top of the coils. One example of a suitable holding means for the blocks is shown in the drawing. Block 72 is held between a pair of gussets 73, 74 xed, by welding or other suitable means, to web 36 and to connecting member 44. These gussets are spaced apart so that the block 72 snugly fits between them and is abutted against the web, against the connecting member, and against the top of coil 22. The block is held in its place by a tang 76 which abuts the outer edge of the block. This tang is attached to web 36 by any suitable means. The blocks 71, 72 need only abut a small area of the top of the coils; therefore they are narrow and do not appreciably restrict the flow of cooling iiuid through the coil.

The various advantages of the coil support described above will be evidenced from a consideration of its construction and how it is associated with the various parts of the core frame. Since the inner side of the coil support abuts against the connect-ing member of the core frame and the grooves of the support abut a crimp or kink in the edge of one of the side pieces of the core frame, the support is prevented from moving in the lengthwise direction of the core frame side pieces. Also, since longitudinally spaced surfaces of the support, defined in the illustrated embodiment by the parallel grooves, are abutted by the two side pieces of the core frame, the support is prevented from moving crosswise of the side pieces of the channel. The support is further immobilized since its bottom portion abuts the core frame and its upper face abuts the bottom of the coil; thus, the support is prevented from lifting or moving in a direction normal to the surface of the web of the channel.

It should be particularly noted that the construction of this improved coil support is such that it easily and quickly is assembled or interiitted with the core frame Without welding, bolt-ing or diicult labor operations.

Although but one embodiment of the present invention has been illustrated and described, it will be apparent to one skilled in the art that various changes and modications may be made therein without departing from the spirit of the invention or from lthe scope of the appended claim.

It is claimed and desired to secure by Letters Patent:

An electrical induction apparatus comprising a magnetic core having a leg and a yoke joined together at a corner of' said core, a coil encircling said leg, a core frame, and a coil support, said frame including a chaunel member having a web and two parallel side pieces perpendicular to the surface of said web, a portion of said yoke being cradled in said channel between said side pieces, said channel having an end portion extending beyond said corner, said support having a portion of one face thereof abutting said coil, the opposite face of said support having two parallel grooves extending completely thereacross, said support being disposed between said end portion and said coil with edge portions of said side pieces extending completely across said opposite face within said grooves to prevent movement of said support crosswise of said channel, the tip of said end portion extending beyond said support and being crimped to abut said support to prevent movement of said support in one direction lengthwise of said channel.

References Cited in the le of this patent UNITED STATES PATENTS Veitch Apr. l2, 1927 Shupe Feb. 2, 1954 OTHER REFERENCES

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