US3810303A

US3810303A - Method of making electrical transformer means

Info

Publication number: US3810303A
Application number: US00165730A
Authority: US
Inventors: J Hoell
Original assignee: Individual
Current assignee: Individual
Priority date: 1969-05-15
Filing date: 1971-07-23
Publication date: 1974-05-14
Anticipated expiration: 1991-05-14

Abstract

This disclosure relates to improved electrical transformer means which has heat transfer surface means for transferring heat outwardly from within electrical coil means of such transformer means to thereby provide optimum electrical performance and to an improved method of making such transformer means and associated coil means.

Description

United States Patent [1 .1

Hoell [451 May 114, 1974 [5 METHOD OF MAKING ELECTRICAL 2,770,785 11/1956 Haagens et a1. 336/61 TRANSFORMER MEANS 2,992,405 7/1961 Ursch 336/61 X 2,592,817 4/1952 McKechnie.. 336/61 [76] Inven or: J h H l 3 9 Glencross, 1,495,323 5/1924 Underhill 29/605 x Cincinnati, Ohio 452l7 3,170,225 2/1965 Gray et al. 29/605 [22] Filed: July 23, 1971 Primary Examiner-Charles W. Lanham [2| I Appl' l65730 Assistant ExaminerCarl E. Hall Related US. Application Data Attorney, Agent, or Firm-John G. Schenk [62] Division of Ser. No. 839,124, May 15, 1969,

abandoned.

- [57] ABSTRACT [52] CI g% This disclosure relates to improved electrical trans- [51] Int Cl Im1f7/06 former means which has heat transfer surface means [58] Fie'ld 61 for transferring heat outwardly from within electrical 2 coil means of such transformer means to thereby pr0- vide optimum electrical performance and to an im- 56] References Cited proved method of making such transformer means and associated coil means. UNITED STATES PATENTS 3,086,184 4/1963 Nichols 336/207 X 10 Claims, 26 Drawing Figures PATENTEDHAY '1 4 i974 SHEET 5 BF 7 FIG-I5 METHOD OF MAKING ELECTRICAL TRANSFORMER MEANS This application is a division of my application Ser. No. 839,124, filed May 15, 1969 now abandoned.

This invention relates to electrical devices and more particularly to high performance electrical transformer means andto an improved method of making same.

The market for electrical transformers such as transformers used in household electrical devices is very competitive. Particularly in the case of a transformer of the type used in a television set, for example, it is especially important that such transformer meet the requirements of, providing continuous high quality electrical performance without overheating, being of light weight, being of small size and being comparatively low in cost. Presently available transformers are deficient in one or more of these requirements.

Accordingly, it is a feature of this invention to provide an improved high performance electrical transformer which is of simple and economical construction.

Another feature of this invention is to provide such a transformer which is light in weight and small in size when compared with present transformers providing equivalent electrical performance.

Another feature of this invention is to provide a transformerof the character mentioned which has improved high performance coil means and such coil means includes means provided therein for transferring heat from within such transformer to the surrounding atmosphere to thereby provide a cooler operating and hence more efficient transformer.

Another feature of this invention is to provide an improved electrical coil meansparticularly adapted to be used in .an electrical transformer and having an improved metal heat transfer surface means for transferring heat from the interior of such coil means to the exterior thereof.

Another feature of this invention is to provide an improved method of economically making a high performance electrical transformer.

Another feature of this invention is to provide an improved method of making such economical and high performance transformer by providing such transformer with inexpensively produced and assembled heat transfer surface means for transferring heat from within such transformer to the surrounding ambient atmosp here.

Another feature of this invention is to provide-an improved method ofmaking high performance electrical coil means particularly adapted to be used in an electrical transformer.

Another feature of this invention isto provide an improved method of making a plurality of such coil means in a simultaneous manner thereby substantially reducing the cost thereof.

Therefore, it is an object of this invention to provide improved electrical transformer means and an improved method of making such improved transformer means having one or more of the novel features of this invention as set forth above or hereinafter shown or described.

Other objects, uses, and advantages of this invention are apparent from a reading of this description which proceeds with reference to the accompanying drawings forming a part thereof and wherein:

FIG. 1 is a perspective view illustrating a plurality of three electrical coil means or coils comprising one embodiment of the improved coil of this invention which is adapted to be used to form an improved electrical transformer and showing such coils being wound simultaneously on rotatable spindle means and particularly illustrating the manner of providing integral spaced apart rectangular passage means in each coil.

FIG. 2 is a perspective view illustrating the rotatable spindle means withdrawn from within the coils of FIG. 1 after such coils have been completely wound and illustrating the three coils severed apart from each other to define individual units.

FIG. 3 is a perspective view illustrating a coil of FIG. 2 broken away from associated core means prior to inse'rtion of metal heat transfer surface means within the passage means provided in such coil. 7

FIG. 4 is a perspective view illustrating one of the coils of FIG. 2 inserted in position within associated transformer core means arid showing a pair of metal heat transfer surface means or strips extending in a rectilinear manner through associated elongated rectangular passage means provided in opposite ends of such coil means prior to forming such strips in position.

FIG. 4A is a perspective view showing the metal strips of FIG. 4 formed into position so that their termi- .nal outer portions lie adjacent exposed outer surface means at each end of such core means and thus define a transformer subassembly ready for the installation of end covers thereon.

FIG. 5 is a perspective view similar to FIG. 4A illustrating another embodiment of this invention also utilizing a coil of FIG. 2 to form another transformer subassembly wherein a pair of preformed substantially Z- shaped heat transfer surface means are inserted in position from each end of each rectangular passage means provided in the associated coil.

FIG. 6 is a perspective view with parts broken away illustrating another embodiment of this invention which is similar to the embodiment of FIG. 5 and which provides guide means within each rectangular passage means to receive and support an associated pair of substantially Z-shaped heat transfer surface means.

FIG. 7 is an exploded perspective view showing one exemplary embodiment of the improved transformer of this invention comprised of the subassembly of FIG. 4A with a pair of covers at opposite ends thereof.

FIG. 8 is a perspective view illustrating another trans former subsassembly used to form another embodiment of the transformer of this invention and particularly showing the arrangement of the transformer core, coil, and a pair of elongated heat transfer surface means.

FIG. 9 is a side elevation of another embodiment of the improved transformer of this invention utilizing the transformer subassembly of FIG. 8.

FIG. 10 is a view on the line 10-10 of FIG. 9.

FIG. 11 is a view on the line 11-11 of FIG. 9 rotated clockwise FIG. 12 is a view looking perpendicular to the lefthand cover as illustrated in FIG. 9 of the drawings.

FIG. 13 is a view on the line 13-13 of FIG. 12.

FIG. 14 is a view on the line 14-14 of FIG. 12.

FIGflS is an enlarged fragmentary view showing a typical indentation or groove provided in each side flange means of each cover to enable insertion of elongated heat transfer surface means therethrough.

FIG. 16 is a fragmentary view similar to FIG. 12 and showing only the lower portion of the right cover provided on the transformer as shown in FIG. 9.

FIG. 17 is a perspective view illustrating a typical improved coil of this invention broken in half and showing the location of a plurality of thermocouples in the center of such coil.

FIG. 18 is a perspective view similar to FIG. 1 of the drawings illustrating a plurality of three electrical coils comprising another embodiment of the improved coil of this invention being wound simultaneously on rotatable spindle means'and using a pair of metal inserts during the winding of such coil means to provide rectangular passage means for later insertion of metal heat transfer surface means therewithin.

FIG. 19 is a view of the coils of FIG. 18 completely wound and showing the metal spacers being withdrawn from within such coils.

FIG. 20 ilustrates the completed coils of FIG. 19 after having been cut with suitable cutting means to define individual coils.

FIG. 21 is a perspective view similar to FIG. 8 particularly illustrating the rectangular passage means in an individual'coil of FIG. 20 after removal of the metal spacers and cutting to the desired length.

FIG. 22, is a perspective view similar to FIG. 18 and illustrating a plurality of three electrical coils being formed simultaneously using a pair of severable spacer means to define rectangular passage means in each coil.

, FIG. 23 is a perspective view showing the three coils of FIG. 22 completely wound.

FIG. 24 illustratesthe coils of FIG. 23. being cut to define individual coils and also showing that such spac ers are left withinthe coils and also cut during the cutting process.

FIG. 25 is a perspective view illustrating one of the spacers being removed fromwithin an individual coil of FIG. 24 to leave a, rectangular passage for insertion of heat transfer surface means therewithin.

While the various features of this invention are hereinafter illustrated and described as being particularly adapted for providing improved electrical transformer means and an improved method of making such transformer means such as, for example,'transformer means of the type used in a television receiver, it is to be understood that the various features of this invention can be utilized singly or in any combination thereof to provide transformer means for other uses and to provide improved electrical coil means for other uses, as desired.

Therefore, this invention is not to be limited to only the embodiments illustrated in the drawings because the drawings are merely utilized to illustrate examples of the wide variety of uses of this invention.

In the exemplary embodiment'of this invention illus trated in FIGS. 4A and 7 of the drawings, an improved electrical transformer means such as a transformer designated generally by the numeral is illustrated. Transformer 30 in this example of the invention has a core designated generally by the numeral 31 comprised of a plurality of laminated metal sheet means a representative few of which have been designated by the numeral 32. Each metal sheet means 32 of this exemplary illustration is comprised of a substantially E-shaped member and an l-shaped member wherein the E- shaped members in adjoining sheet means 32 face in opposite directions in a known manner and for known reasons. 1

Transformer 30 has improved electrical coil means shown as an electrical coil 33 supported therewithin and coil 33 has heat transfer surface means shown as a metal heat transfer surface 34 extending from within coil 33 to the exterior thereof for dissipating heat from within coil 33. In this example of the invention a pair of transfer surfaces 34 is provided so that each extends from an opposite end of coil 33 with such coil installed in position with core 31 in surrounding relation.

The installation of coil 33 in position within core 31 and the placement of the heat transfer surfaces 34 at opposite ends of coil 33 define a transformer subassembly which for convenience and ease of description will be designated by the numeral 35. The use of heat transfer surfaces 34 and the simple manner of installing such surfaces in position in coil 33 provide an efficient transformer which gives improved performance and is economical to construct as will be described in detail subsequently.

Housing means shown as covers and 41 are provided for transformer 30 and adapted to be installed in position at opposite ends of transformer 30. Each

cover

40 and 41 is preferably fastened in position by a plurality of four bolts each designated by the numeral 42.

Each bolt 42 extends through an associated opening 43 in cover 41, an opening 44 in laminated core 31, and a threaded opening 48 provided in cover 40. After assemblying coil 33 within core 31 and inserting metal heat transfer surfaces 34 in position at each end of coil 33, covers 40 and 41 are fastened in position to thereby define a compact easily assembled transformer.

Coil 33 of this example is comprised of a number of layers which are wound starting at one edge and wound to the opposite edge it being understood that each layer is wound one on top of the other starting from the center of such coil and winding out-wardly in a known manner. The electrical wire used in each layer of winding is preferably insulated by spray coating and suitable electrical insulation such as treated paper, or the like,

i is placed between adjoining layers.

The primary winding of transformer 30 is wound from one edge to the opposite edge as above described and is further preferably arranged immediately adjacent the center of the coil and wound outwardly, the secondary winding is wound on top of the primary winding, and one or more secondary filament windings may be wound on top of the secondary winding of transformer 30, as desired and depending upon the particular application. The wire used for the various windings may be of copper, aluminum, or other suitable electrical conductor; as desired.

Core 31 in this example of the invention has a pair of exposed outer surface means each designated by the numeral 50 and each defining the opposite ends of core 31. Outer surface means 50 are arranged in parallel spaced apart relation and are each substantially planar surfaces with the exception, of course, of opening means therein for receiving portions of coil 33. Electrical coil 33 is supported within core 31 so that a plurality of its winding layers are arranged outwardly of exposed planar outer surface means or outer surface 50 at each end and such plurality of layers arranged outwardly of each surface 50 have been designated generally bby the numeral 51.

Coil 33 has preformed slot means shown as a pair of substantially rectangular slot or passage means designated by the numeral 52 provided adjacent each and thereof. Each slot 52 extends completely across the full height, as designated by the numeral 53, of coil 33 and each slot 52 is defined between a pair of adjoining layers of the windings comprising coil 33. The construction and arrangement of core 311 and coil 33 is such that each slot 52 is positioned so that it is arranged outwardly of an associated exposed planar surface 50.

In the embodiment of this invention illustrated in FIGS. 4A and 7 of the drawings, a single strip of metal 34 extends beyond opposite ends of slot 52 at each end of coil 33 and provides a means for transferring heat from within coil 33 to the exterior thereof. Each strip 34 is inserted in its associated rectangular passage 52 and extends completely through coil 33.

Passage 52 in this example of the invention is defined by a pair of identical insulating and spacing strip means shown as a pair of strips each designated by the numeral 60 and each provided so as to extend the full height of coil 33. Each strip 60 is formed as an integral part of coil 33 and is cut flush with the side edges of such coil. Cooperating side surfaces of a pair of strips 60 define corresponding side surfaces of rectangular passage 52. v

Each strip 50 is of sufficient thickness so that the resulting rectangular slot 52 enables easy insertion. of strip 34 therethrough. The manner of forming coil-33 with strips 60 in position and the manner of forming other coils capable of being used in the transformer which are similar to coil 33 and which do not provide integral strips similar to strips 60 will be described in more detail subsequently.

As shown particularly in FIG. 4 of the drawings, each strip 34 is inserted in position in its associated slot 52 at each end of coil 33 with its opposite ends extending beyond the sides of core 31 as illustrated. Suitable forming means is provided for forming and shaping the outer ends of elongated strip 34 so that a portion 54 at each end is formed into position against outer surface 50 at each end as illustrated in FIG. 4A of the drawings. Each portion 54 lies against outer surface 50 so the terminal end thereof lies flush with the associated side of core 31. The resulting transformer subassembly 35 is illustrated in FIG. 4A and as a part of transformer 30 in FIG. 7 of the drawings.

Each

cover

40 and 41 has recess means shown as a groove 55 defined in each of its side edges.' Each groove 55 is adapted to receive an associated portion 54 of strip 34 therethrough and thereby enable inside surface means designated by the same numeral 56 on each

cover

40 and 41 to be held tightly against an associated outer surface 50 at each end of transformer core 31.

Thus, it is seen that in this exemplary embodiment of the invention an improved coil 33 has been provided which has preformed slot means or a pair of preformed rectangular passages 52 provided in its opposite ends. Each passage 52 extends substantially completely across each end of coil 33 and each passage 52 is defined by a pair of spacing and insulating strips 60 which are integrally formed between a pair of winding layers where it is desired to provide each strip 34 for transferring heat from within coil 33.

Another embodiment of this invention is illustrated in FIG. 5 of the drawings wherein the transformer subassembly is practically identical to the transformer subassembly 35; therefore, such transformer subassembly will be designated generally by the numeral 35A and parts of subassembly 35A which are identical to corresponding parts of subassembly 35 will be designated by the same numeral as subassembly 35 also followed by the letter designation A and not described again in detail. Only those component parts of subassembly 35A which are different from corresponding parts of subassembly 35 will be designated by a new numeral also followed by the letter A" and described in detail.

In this example of the invention metal surface means used to transfer heat from within coil 33A comprises a pair of metal strip means arranged in coil 33A at each end thereof and each designated by the numeral 62A. Each metal strip means or metal strip 62A is supported within its associated passage 52A and extends outwardly from the center portion of coil 33A.

Each metal strip means or metal strip 62A in this example is substantially Z-shaped with a portion thereof designated by the numeral 63A lying adjacent, preferably against, an associated planar surface 50A of core 31A. Each substantially Z-shaped strip 62A is preformed to the configuration illustrated in FIG. 5 of the drawings and such preformed strip means is then inserted in position in an associated coil 33A.

Another exemplary embodiment of this invention is illustrated in FIG. 6 of the drawings. In the embodiment of FIG. 6 the transformer subassembly illustrated is practically identical to transformer subassembly 35A; therefore, such subassembly will be designated generally by the numeral 358 and parts of subassembly 35B which are identical to corresponding parts of subassembly 35A will be designated by the same numeral as in subassembly 35A also followed by the letter designation B and not described again in detail. Only those component parts which are different fromm corresponding parts of subassembly 35A will be designated by a new numeral also followed by the letter designation B and described in detail.

The basic difference between subassembly 35B and subassembly 35A is that guide means shown as a guide 653 has been provided as an integral part of subassembly 358. A guide 658 is preferably provided in coil 338 in each end thereof and each guide is preferably made of a suitable rigid material such as metal, or the like.

Guide 5513 is preferably inserted and formed as an integral part of coil 338 during the forming of such coil and it will be appreciated that such guide assures that heat transfer surfaces 62B may be easily inserted in position without damaging the adjoining winding layers of coil 338. Guide 65B further assures that the rectangular passage means 52B does not collapse between spacers B and is particularly adapted to hold Z-shaped strips 628 in position.

Guide B has a flat main portion designated by the numeral 66B and a pair of hooking outer terminal ends designated by the numeral 678. Outer ends 678 are arranged so as to overlap a part of the main portion 668 of guide 65B along the top and bottom thereof and portions67lB are arranged substantially coplanar and parallel to main portion 668. The distance between the inside surfaces of portions 67B and the inside surface of main portion 668 is such that each member 62B may be easily slid into position yet the clearance is sufficient within coil 338 so that it extends substantially across the major length of rectangular passage 52B and hence across what has been referred to as the height of coil 338. Each guide member is preferably adhesively fastened in position during the forming of coil 338.

It will be appreciated that each

transformer subassembly

35A and 35B illustrated and described above may be substituted for the transformer subassembly 35 provided in the transformer assembly 30 of FIG. 7 to thereby provide a complete transformer unit. The differences in the

transformer subassemblies

35, 35A, and 35B have been described in detail above and upon fastening the end covers 40 and 41 in position on

subassembly

35A or 35B the resulting transformer provides improved performance superior to presently known transformers. Furthermore, the unique and easily and economically provided heat transfer surface means 34, 62A, and 628, for transformer subassemblies 36, 35A, and 358 respectively assure efficient outward transfer of heat from within their associated coils.

Another exemplary embodiment of this invention is presented in FIGS. 8-16 of the drawings wherein an improved transformer, transformer subassembly, and associated component parts are illustrated. The transformer subassembly of this latter embodiment, and shown in FIG..8, is practically identical to transformer subassembly 35 illustrated in FIG. 4A and 7 of the drawings; therefore, such transformer subassembly will be designated generally by the numeral 35C and parts of subassembly 35C which are identical to corresponding parts of subassembly 35 will be designated by the same numeral as' subassembly 35 also followed by the letter designation C and not described again in detail. Only those component parts which are different from correspondinng parts of subassembly 35 will be designated by a new numeral also followed by the letter designationC and described in detail.

Because ofits similarity to transformer 30, the complete transformer of FIGS. 8-16 has been designated by the numeral 30C and the end covers and fastening means therefor of transformer 30C have been given new numerals also followed by the letter C and described in detail.

As seen in FIG. 8 of the drawings, transformer subassembly 35C has an elongated metal heat transfer surface means or strip extending through its rectangular passage means 52C which is more than twice the length of rectangular passage 52C and is designated by the numeral 70C. Each metal strip 70C is adapted to be shaped or arranged such as by bending, or thelike, in an arcuate path, see FIG. 11, and fastened together adjacent its opposite terminal ends to define a substantially D-shaped tubular heat transfer surface means. The arcuate portion of such D-shaped heat transfer means is shown in FIG. 11 as being arranged outwardly.

with fastening means provided on the covers for transformer 30C to fasten each strip in position.

Each strip C provides an extended length heat transfer surfaces which has a neat appearance and yet is quite compact so as to assure the overall size of transformer 30C is quite small. It will be appreciated, however, that in some applications of this invention it may be desired to shape or cut or add additional surface means to metal strips 70C so as to provide even larger heat transfer surface areas for more efficient heat dissipation.

As seen particularly in FIG. 8 of the drawings, flux shield means shown as a flux shield 73C is provided over the top and bottom portion of transformer subassembly 35C. The flux shield 73C has a width which is substantially the same as the height 53C of coil 33C.

Insulating sleeve means is also provided around elongated metal strip 70C and such insulating sleeve means is shown as a thin sleeve 75C which is made of an insulating material such as rubber, or the like. Sleeve 75C extends along the central portion of elongated strip 70C and is of sufficient length that it will extend beyond the end cover means provided on transformer 30C as will be subsequently described in detail. The rubber sleeving 75C is used to thermally isolate each elongated metal strip 70C from core 31C and from adjoining cover means.

As seen particularly in FIGS. 12-16 of the drawings, cover means is provided for covering both ends of transformer subassembly 35C. The cover means comprises a left cover C, shown in FIGS. 12-15, and a right cover 81C, illustrated in FIG. 16 of the drawings.

Left cover 80C has a plurality of four openings each designated by the numeral 82C provided therein adjacent its corners and openings 82C are of a size and arrangement so as to be easily aligned in cooperating relation with a plurality of four openings each designated by the numeral 44C provided in core 31C of transformer subassembly 35C.

Right cover 81C is basically identical to cover 80C with the exception that cover 81C has an opening therein designated by the numeral 85C for extending electrical leads shown as a plurality of electrical wires at 86C from within transformer 30C. Cover 81C has a plurality of four openings each designated by the numeral 87C and provided herein adjacent its four corners. Openings 87C of cover 81C are adapted to be placed in aligned relation with associated openings 44C at the opposite end of transformer subassembly 35C.

With each set of

openings

82C, 44C, and 87C in aligned relation at each corner of transformer 30C suitable fastening means such as a bolt 90C is provided for extending through each associated set of openings to hold covers 80C and 81C in position. Each bolt 90C cooperates with a threaded nut 91C which in this example of the invention is arranged to bear against the outside surface of cover 81C to thereby clamp covers 80C and 81C on opposite sides of the transformer subassembly 35C.

Each cover 80C and 81C has a preferably centrally arranged threaded stud means or threaded stud designated by the numeral 92C. Each threaded stud is fixed to its associated cover in any suitable manner as by welding, for example, and is adapted to receive an insulating sleeve 93C in surrounding relation thereabout and has a cooperating threaded nut 94C on its outer terminal end.

Each cover 80C and 81C has indentation means or a shallow groove designated by the-numeral 95C in each instance which is provided therein along its opposite side edges and illustrated in enlarged detail in FIG. of the drawings. Indentation 95C has a height corresponding to the combined thickness of strip 70C and sleeve 75C so as to provide adequate clearance between each associated cover and core 311C.

The manner of utilizing each elongated strip 70C, which is over twice the height of coil 33C, in a most efficient and compact manner is particularly illustrated in FIGS. 8 and Ill ofthe drawings. Thus, as seen in FIG. 11, an insulating washer or sleeve 93C is first placed in position around an associated stud. Each end of strip 70C is then passed through an associated groove 95C and bent around its associated end cover so that each opening 72C is placed in surrounding relation around stud 92C with a portion of each strip 70C bearing against and being supported against inward movement by sleeve 93C, the associated nut 94C is then threaded in position against strip 70C. Of course, the same procedure is carried out at each end of transformer 30C.

Each insulating spacer 93C holds strip 70C in the desired spaced relation at each end of the transformer 30C thereby assuring that there is adequate air space at each end as shown at 96C to assure optimum heat transfer to the ambient atmosphere. Each elongated strip 70C is thus installed in position inexpensively.

As seen. in FIG. 11 of the drawings, the overall size of transformer 30C is'comparatively small while the area of heat transfer surface utilized at each end thereof is quite large and, of course, it is very inexpensively made because it is produced, in effect, by an elongated inexpensive strip that is bent to define the D- shaped tubular form illustrated. 7

'Thus, it is seen that

transformer subassemblies

35, 35A, 35B, and 35C each utilize metallic heat transfer surfaces extending from associated rectangular opening means provided in each end thereof to transfer heat from within their associated coils to the exterior thereof in an inexpensive and efficient manner. The heat transfer surface means utilized in each embodiment of this invention may be made of any suitable material and is preferably made of thin metal strip means.

Metal strip means containing copper or aluminum may be used effectively as heat transfer surfaces.

In each exemplary transformer subassembly illustrated and described in this disclosure of the invention the core utilized is of standard construction which comprises layers of E and I sections suitably stacked toge ther in a known manner and as previously mentioned and the overall peripheral outline of each core is in the shape of a parallelepiped. However, it will be appreciated that any shape and construction of core may be used as desired.

Also, the exemplary transformers presented in this disclosure all utilize what is commonly referred to as shell-type core; however, the improved manner of transferring heat from within the particular transformer involved to the exterior thereof may also be effectively utilized in a core-type transformer or any other transformer construction not clearly of either of these two common types. In short, it is sufficient to provide a transformer coil structure of any configuration and wherein such improved elongated slot'means is provided therethrough for receiving an inexpensively produced metallic heat transfer surface means for transmitting heat from the interior of such coil structure to the exterior thereof.

An exemplary embodiment of improved electrical coil means of this invention and method of making same is illustrated in FIGS. 1 and 2'of the drawings wherein rotatable spindle means shown as a rotatable spindle 100 is provided to enable making a plurality, three in this example, of coils 33 in a simultaneous manner. Rotatable spindle 100 is preferably of rectangular cross-sectional outline to correspond to the desired rectangular opening to be provided in each coil 33.

Spindle 100 is rotated in any known suitable manner so as to wind layers of coils one on top of the other outwardly from the outer surface of such spindle. Inasmuch as three coils are being wound simultaneously three sources of coil conductor material means or electrical wire are shown each designated by the numeral 102. Wires 102 are provided from a suitable source such as supply spool means which rotates simultaneously with spindle 1100 to unwind the wire being wound on each coil 33.

Each wire used in each coil 33 is preferably electrically insulated as by thin film insulation and suitable electrical insulation is provided between each layer of wire. The insulation provided between each layer of wire is preferably an insulation which is inexpensive and easily cut such as paper, or the like, which may be suitably treated. Each layer of paper insulation is designated by the same numeral 103 with only the outer easily visible layer being so designated in the drawings.

The coil winding method is quite simple and easy to achieveand in this example requires that a few inner layers of each coil 33 be wound. Then a plurality, four in this example, of elongated insulating and spacing strips each designated by the numeral are placed in position against an inner winding at a predetermined point during the winding process. Suitable fastening means such as adhesive means'may be used to adhesively hold such strips in position.

The'outer windings for each coil are then wound so as to completely form each coil 33. Each rectangular passage means 52 is defined in each case by opposed layers of insulation 103 defining two opposed surfaces of such passage and the remaining two surfaces of passage 52 being defined by strips 60. Each layer of paper insulation that is placed between adjoining coils 33 extends as a continuous sheet across all three coils and the paper layers are simultaneously cut once the three coils 33 are completely defined.

' Suitable cutting means of any known type is provided for cutting between adjoining coils 33 in this example of the invention to define three individual coils. The cutting action is preferably achieved by rotary knife means and such cutting action does not tend to collapse passages 52. Each coil 33 is then utilized with heat transfer surface means of the type illustrated in FIGS. I

4A, 5, 6, and 8 of the drawings to provide an improved transformer of this invention.

The particular locations in each coil 33 at'which the rectangular elongated slots 52 are provided will vary in each particular application of this invention. However, it will be appreciated that each rectangular slot is generally provided approximately centrally across the thickness of the particular windings or layers provided in any individual coil at the point of maximum heating and thereby is able to transfer heat from the interior of such coil to the exterior thereof in a most efficient manner.

Another exemplary embodiment of the improved coil -means of this invention and method of making same is illustrated in FIGS. 18-20'of the drawings. The coils of this latter embodiment are practically identical to coils 33 with the exception that spacers 60 which are an integral part of each coil 33 have been eliminated; therefore, such coils will be designated by the numeral 33 followed by the letter designation M. Component parts of each coil 33M and illustrated components for is providdd at opposite sides of coils 33M which are being simultaneously wound in the same manner as coi-ls 33..Each member has an opening 111M therein adjacent one end thereof.

A few inner layers of each coil33M are first wound in position then at each location where it is desired to provide a rectangular slot 52M a metal spacer 110M is placed in position and the remainder of the coil 33M wound as desired. In this example two rigid members 110M are used and once the winding is completed such members are removed as shown in FIG. l9by inserting a suitable tool through openings 111M and pulling. Coils 33M are then cut apart so as to define the three individual coils.

Each coil 33M may be used interchangeably with coil 33 as used in all previously presented embodiments of this invention and, of course, it is only necessary to insert the appropriate metallic heat transfer surface means within an associated slot 52M.

Another exemplary embodiment of this invention is illustrated in FIGS. 22-25 of the drawings wherein a plurality of three coils'each designated by the numeral 33N are formed simultaneously in a similar manner as coils 33M and coils 33N after being formed are identical to coils 33M; therefore, as inthe previous example, coils 33N and components used to make such coils will bear the same numerals as corresponding components of the next previous embodiment also followed by the letter designation N in this letter embodiment.

The spacing inserts 1l0N used to make slots 52N in each coil 33N are made of a severable material such as a thick cardboard, or the like. A few layers of wire are wound on spindle 100N as seen in FIG. 22, severable inserts 110N are then suitably held in position, then the remainder of each coil33N is wound in a simultaneous manner by rotating spindle 100N. After the coil is completely defined it will appear as illustrated in FIG. 23 of the drawings.

Suitable cutting means shown as rotary cutting means 113N is provided for cutting through the elongated wound structure of FIG. 23 to define a plurality of three individual coils 33N. Each individual coil 33N is cut while also cutting spacers llN and such spacers remain in each coil 33N.

Tool means such as a rod 1 MN is provided for pushing cut each severed cardboard spacer and withdrawing it. This procedure is carried out as shown in FIG. 25 so as to withdraw the spacers from each coil 33N and thereby define the rectangular passage means 52N.

Each coil 33N may be utilized in the same manner and in all embodiments of the invention as previously illustrated and described in connection with coil 33.

While a plurality of three coils have been illustrated and described as being made in a simultaneous manner in three examples of making coils presented in this disclosure, it will be appreciated that any number of coils may be made simultaneously and that it is merely necessary to provide a rotatable spindle of proper size and a suitable number of lead in wires. The method of this invention may be used to make a dozen coils, for example, in a simultaneous manner. Obviously a single coil may be made also, if desired, using the technique described above to define passage means for the heat transfer surface means.

Thus, it is seen that an improved method has been shown for making coils each having substantially rectangular passage means therein for receiving and supporting heat transfer surface means adapted to be inserted therein to transfer heat from within each coil to the exterior thereof. Furthermore, it will be appreciated that this invention enables the forming of such high performance coils in an economical manner and such coils may be used not only in transformer application but in other applications where it is desired to provide cool operating high performance coils.

Considerable tests have been conducted to establish the effectivelness of the improved and simply made and installed heat transfer surface means of this invention and to illustrate the gains to'be made by utilizing such heat transfer means. It has been shown, for example, that upon designing a transformer within specified performance requirements, the improved heat transfer surface means of this invention and the method of forming same make it possible to design a cooler operating more efficient transformer. The net effect is that this invention makes possible delivery of a transformer to given customer requirements which is lighter in weight, smaller in size, uses less materials, and thus results in a comparatively less expensive transformer.

A series of tests conducted to verify the improved effectiveness of the heat transfer surface means of this invention was conducted in which various coils had thermocouples installed at six positions as shown in FIG. 17 of the drawings. Identical coil structures were used in the associated transformers that were tested and such transformers were identical except they were modified as indicated in the following table and under test conditions as presented therein. The reference to cased means that end covers were fastened in position on each coil and the impregnated transformers were impregnated with a suitable known material. The thermocouples were placed at positions designated by the numerals R through W in FIG. 17.

Test Conditions: E.I.A. heat chamber 40 C ambi- SWP- Input voltage V 60 Cycles AC power Secondary loaded.

Ends of heat transfer surfaces were bonded between core and case.

Test No. l 2

lmpregnated No No Cased Yes Yes Metal Heat Transfer Surface No Yes Thermocouple Position Temperature in Degrees Centigrade R. Between inside insulating layer and Core 119 112 S. Between inside insulating layer and First layer (L) of Primary (Pri) 141 127 T. Between 3L and 4L of Pri. l7 136 U. Between Fri. and Secondary (Sec.) 153 l 19 V. Between 3L and 4L of Sec. 147 I27 W. Between Sec. and Sec.

Filament [33 121 Thus, it will be seen from the above table that by using the improved heat transfer surface means of this invention lower operating temperatures were encountered at all locations within the particular coils tested and particularly near the center portions of each coil.

Terms such as top, bottom, upper, lower, sides, ends, and the like, have been used in this disclosure for ease of description and merely to describe the positions of various components of the transformers and transformer subassemblies as illustrated in the drawings and such terms should not be considered as limiting the scope of this invention in any way.

Thus, it is seen that this invention provides improved transformer mens which is of simple and economical construction and which is of light weight and small size as compared to existing transformer means.

Further, this invention provides an improved method of making such transformer means.

While the form of the invention now preferred has been disclosed ay required by statue, other forms may be used, all coming within the scope of the claimed subject matter which follows.

What is claimed is:

l. A method of making an improved electrical transformer comprising the steps of, providing metal core means having exposed outer surface means at opposite ends of said core means, providing electrical coil meany having a plurality of winding layers adapted to be supported exteriorly of said exposed outer surface means, forming slot means between a pair of adjoining layers of said plurality of layers, said slot means extending across the full height of said coil means, supporting said coil means within said metal core means with said slot means arranged exteriorly of said exposed outer surface means, providing metal heat transfer means, and placing said metal heat transfer means within said slot means, whereby said metal heat transfer means extends outwardly from said slot means and transfers heat from within said assembled transformer to the exterior thereof to provide an improved more efficient transformer.

2. The method as set forth in claim 1 in which said step of providing metal heat transfer means comprises providing metal strips and said placing step comprises extending said metal straps from opposite ends of said slot means beyond associated opposite ends of said coil means.

3. The method as set forth in claim 2 in which said step of forming slot means comprises forming substantially rectangular passage means in said coil means which extends completely across said coil means between said pair of adjoining layers and said placing step comprises extending said elongated metal strips beyond opposite ends of said rectangular passage means and hence beyond associated opposite ends of said coil means.

4. The method as set forth in claim 3 in which said step of providing elongated strips comprises providing a single elongated flat metal strip, said placing step comprises inserting said elongated metal strip so that it extends completely through said rectangular passage means and exteriorly of opposite coil ends thereof, and comprising the further step of shaping both opposite strip ends thereof so they lie adjacent said outer surface means.

5. The method as set forth in claim 4 in which, said step of providing a single elongated flat metal strip comprises providing an elongated strip which is more than twice the length of said rectangular passage means, said shaping step comprises shaping the opposite ends thereof so each extends in an arcuate path, and comprising the further step of fastening said ends together to define a tubular substantially D-shaped metal heat transfer means.

6. The method as set forth in claim 5 comprising the further steps of, providing cover means adapted to enclose said plurality of layers, fastening said cover means against said exposed outer surface means to enclose said metal plurality of layers, and fastening said strip ends against said cover means during said shaping step.

7. The method as set forth in claim 3 in which said step of providing metal strips comprises providing a pair of metal strips and said placing step comprises inserting each of said metal strips from opposite ends of said rectangular passage means so that they abut each other adjacent the center portion of said passage means.

8. The method as set forth in claim 7 comprising the further step of, shaping each of said pair of metal strips prior to inserting each of said strips in position during said placing step so as to define a substantially Z- shaped metal heat transfer means, and said placing step further comprises placing a portion of each of said strips adjacent said outer surface means.

9. The method as set forth in claim 7 further comprising the steps of, providing guide means adapted to hold said pair of metal strips in position, supporting said means within said rectangular passage means, and said placing step comprises'inserting each of said strips from opposite ends of said rectangular passage means into said guide means.

10. The method as set forth in claim 1 in which said placing step further comprises arranging said metal strips immediately adjacent said outer surface means, and comprising the further steps of providing cover means adapted to be fastened against said outer surface means and fastening said cover means against said outer surface means with said metal strips having its opposite ends arranged between said cover means and said outer surface means.

Claims

1. A method of making an improved electrical transformer comprising the steps of, providing metal core means having expOsed outer surface means at opposite ends of said core means, providing electrical coil meany having a plurality of winding layers adapted to be supported exteriorly of said exposed outer surface means, forming slot means between a pair of adjoining layers of said plurality of layers, said slot means extending across the full height of said coil means, supporting said coil means within said metal core means with said slot means arranged exteriorly of said exposed outer surface means, providing metal heat transfer means, and placing said metal heat transfer means within said slot means, whereby said metal heat transfer means extends outwardly from said slot means and transfers heat from within said assembled transformer to the exterior thereof to provide an improved more efficient transformer.

8. The method as set forth in claim 7 comprising the further step of, shaping each of said pair of metal strips prior to inserting each of said strips in position during said placing step so as to define a substantially Z-shaped metal heat transfer means, and said placing step further comprises placing a portion of each of said strips adjacent said outer surface means.

9. The method as set forth in claim 7 further comprising the steps of, providing guide means adapted to hold said pair of metal strips in position, supporting said means within said rectangular passage means, and said placing step comprises inserting each of said strips from opposite ends of said rectangular passage means into said guide means.