US2845694A - Means and method for forming coils - Google Patents

Description

Aug. 5, 958 R; G. LE TOURNEAU 2,345,694

MEANS AND METHOD FOR FORMING COIL-S Original Filed June 26, 1950 4 Sheets-Sheet 1 805527 6. A: ibueuua,

INVEN TOR.

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flrraelvadr Aug.'5, 1958 R. G. LE TOURNEAU 2,845,694

MEANS AND METHOD FOR FORMING corps Original Filed June as, 1950 4'Sheets -Sheet z Eoaeer 6'. Le Kauai/54v.

INVEN TOR.

Aug. 5, 1958 R. G. LE TOURNEAU MEANS AND METHOD FOR FORMING COILS 4 Sheets-Sheet 3 Original Filed June 26, 1950 205.527 6. L5 7&(724/540.

IN V EN TOR.

drive/ways Aug. 5, 1958 R. G. LE TOURNEAU I MEANS AND METHOD FOR FORMING COILS 4 Sheets-Sheet 4 Original Filed June 26, 1950 uwszvroa wax United States Patent MEANS AND METHOD FUR FORMING COILS Robert G. LeTourneau, Longview, Tex., assignor to R. LeTourneau, lnc., Peoria, liL, a corporation of California Original application June 26, 1950, Serial No. 170,272. Divided and this application March 8, 1954, Serial No. 414,576

7 Claims. (Cl. 29-15557) This invention relates to means and method for forming windings for installation on a dynamo-electric machine, the present application being a division of my copending patent application Serial No. 170,272, filed June 26, 1950, now Patent No. 2,688,104.

An object of this invention is to provide a unique method of forming coils for installation as field windings on a rotor whereby a maximum amount of the iron in the rotor is available for excitation of the field.

Another object of the present invention is to provide a method of forming windings for installation as a field windin on a rotor having a small number of widely spaced slots wherein the slots are filled with a maximum of conducting material as compared with conventional machines.

A further object of the present invention is to provide an improved coil winding machine used to form two layer coils of a single wire in which the current flow is in the same circuitous direction in each layer and in which the terminals for each layer come out at the same relative location.

Briefly, the present invention contemplates improved means and techniques involving a supply spool containing wire which is to be fabricated in double layer coils, a storage spool and a coil form. Initially a first portion of the wire from the supply spool is reeled onto the storage spool; and then, without severing the connecting wire between such first portion and the remaining portion of the wire on the supply spool, a second portion of wire is reeled directtly onto the coil form to form the first layer of the coil. Then the wire connecting the second portion of the remaining portion of the wire on the supply spool is severed. Thereafter, such first portion of Wire stored on the storage spool is transferred onto the coil form to form the second layer of the double layer coil.

The features of the present invention which are believed to be novel are set forth with particularity in the appended claims. This invention itself, both as to its organization and manner of operation, together with further objects and advantages thereof, may be best understood by reference to the following description taken in connection with the accompanying drawings in which:

Figure 1 represents a side elevational view in half section of a complete generator employing windings formed and installed in accordance with this invention.

Figure 2 is a fragmentary end view showing details of coils in a slot winding.

Figure 3 is a fragmentary side view of a section along lines 33 of Figure 2, showing the extension on the winding retaining wedge.

Figure 4 is an end view of the end of the rotor opposite the brush mechanism showing the windings in the process of being installed.

Figure 5 is an end view of the opposite end of the rotor showing the manner in which the separate windings are connected with each other and to the slip rings.

Figure 6 is an isometric view of one coil section show- ICC ing the two layers of which it is composed, one layer being shown diagrammatically.

Figures 7 and 8 are views of apparatus used in winding the coils and serve to illustrate twosteps in the method of forming the coil section shown in Figure 6.

Figure 9 is a top plan view of the machine M of Figures 7 and 8.

Figure 10 shows in enlarged form a portion of the structure shown in Figure 5, and shows the manner in which the individual coil sections are serially connected to form a single composite winding.

Figure 11 shows various size forms used on the coil winding machine employed in carrying out certain features of this invention.

Referring now more particularly to the drawings, in Figure 1 a generator having a rotor is seen to consist basically of a stator frame 1 supporting stator windings 2; a rotor 3 journalled for rotation'in the frame and having its shaft carrying a fan 4 at one end and an engine crankshaft C at the other end; a terminal block 5; and a slip ring mechanism 6 for supplying exciting current to the rotor.

The slip ring mechanism 6 may be of any desired construction but I prefer to make it in accordance with the construction shown in my application Ser. No. 117,582, entitled Slip Ring Arrangement, filed September 24, 1949, now U. S. Patent No. 2,623,188.

The stator frame 1 includes front and rear end bells 7 and 8 spaced apart and secured to circumferentially spaced channels 9, which channels by means of annular rings 10 support the stator (or armature) laminations 11, and hold them in place.

These laminations 11 include skewed stator slots 2a to receive stator windings 2. End bell 7 includes a bearing retainer 12 which supports stud 13 of slip ring mechanism 6. Bearing retainer 12 is sealed from rotating adapter 14 by a pair of conventional piston rings 15 for a purpose later described. The opposite end bell 8 contains a bearing retainer 16 to which plate 17 is secured by capscrews 18 to enclose ball bearing 19.

The rotor 3 as seen in Figure 1 includes a shaft'20 upon which a stack of rotor (or field) laminations is keyed, the laminations are then pressed between end plates 21a and clamped in place on the shaft between'hub 22 and lock nut 23. At the fan end, rotor 3 is spline connected to adapter 14 by an arrangement shown in detail in my co-pending application Serial No. 727,806, filed February 11, 1947, now abandoned. Adapter is in turn rotatably supported by ball bearing 24 and directly connected to fan spacer 25 by capscrews 26. Bearing 24 encloses an oil pocket 24a which is sealed by the previously mentioned piston rings 15. At its end opposite fan 4, the rotor 3 is splined to a drive adapter 28 which is itself locked in place by splined nut 29 and to which bolt plate 30 is attached by capscrews 31. Plate 30 then engages crankshaft C or any other suitable driving means to rotate the generator rotor. The rotor laminations 21 and their end plate 21a both contain winding slots 32 in which windings 33 are inserted. Cylindrical covers 34 and 35 enclose the exposed end legs 33a of windings 33 and are attached to the rotor by capscrews 36 after being centered on wedge extensions 37. Both end covers include a circular end member 34b and 35b and a cylindrical wall 34a and 35a. One end cover 35 includes blades 38 for circulation of air and heat away from the windings, and to create a low pressure area to assist the blast from fan 4 in creating circulation through the generator as indicated by the arrows F, G, and H. The end members 3412 and 35b include central openings 57 and 58 and the end members receive bolts 36 which attach the end covers to rotor 3 by means of tapped holes 56.

flags-.33- against radial displacement.

The, operation of the cooling system of this generator represents the direction of the blast of air from fan 4. When this blast reaches end bell 7, it passes through holes 4fi-therein toreaeh area 60 within frame 1. From areav 60 the blast B is separatedintoseparate paths as shown by; arrows. F, G, and H., Path F goesv between stator laminations: 1L and; the circumference 61 of rotor 3. Path. G: goes through circular opening 57 of end cover 34iandzfrom there; through openings 39b.formed between depending ribs 39a of vent plate 39 and the bottom 62 Qff' slot 32.. Ribs 39:: are welded or otherwise secured to ahoriaontal piece. 39c of vent plate 39. Path H goes through opening 57 andinto holes 59 of rotor 3. All three paths come together in area 63 adjacent end. bell 8iandqiass.betweenv channels 9 tothe outside air as shown y" rrows: K.

It is observed that the vent plates 39v serve not only to; support the windings in their slots but also form a part of the air; cooling system. itis, ofcourse, desirable to produce an air flow therethrough which is impeded as low as possible and which is.not,afiect ed appreciably by turbulence in the air stream. For, this reason, the end covers 34, 35, besides serving as winding retaining members, present a smooth continuous surface to the air stream induced-by the fan 4 thereby eliminating turbulence and windage losses which otherwise might: result from the air stream impinging on. the exposed; coil ends. It is further observed that the end cover; 36 has mounted thereon the blade 38 for aiding and inducing. air flow through the machine. Thus, the; retaining, means provided herein is functionallyinterrelatedand forms a part of the cooling system.

In Figures,- 2, and 3, the winding retainer 40 used to holdlthelongitudinal legs 33b of windings 33 in slots 32 is shown in detail to consist of inwardly bent wedge 41 with semi-circular cups 42 at the lateral edges thereof andlongitudinal extensions 37 which. project beyond the rotor laminations 21 and end plates 21a at each end. At thetop of side walls 53, there is located a semi-ciroulankeyway 43 which aligns with cup 42 to form a full circulan opening and to receive a copper rod key 44 which in addition; to, holding wedge 41 in position, acts as a shading coilfor the adjacent poles N and S. Steel bars 5.5. are; equally spaced around the circumference 61 of rotor; 3, between copper rods 44 of successive slots 32. Both the copper-rods 44and the steel bars are welded. as; at165; to end; plates 21a so that they serve as amortis- Seur windings and shading coils. This construction is similar; to thatshown in my co-pending applicationSerial No.,99,;44l,.filedl June 16, 1949, now abandoned.

Extensions 37 of wedges 41 are machined (as at 37a) concentric to but of slightly less diameter than the circurnference 611 of rotor- 3 for the purpose of holding and centeringrwinding covers 34 and 35, as shown in Figures 1; and 4. These winding covers closely surround end legs- 3300f winding 33 and are wedged where necessary by insulating-sheets 45a and fibre pieces 45 to securely hQld. the; legs 33a in position. Sheets 45a are inserted where needed'in space 34c between cover 34 and windings 33;. From this description it will be seen that the windings- 33 will be secure with the rotor against any distortion which would beoccasioned by the high speed of the rotor (and the resulting centrifugal force), since both the. longitudinal legs 3312. are held by wedges 41 and the end legs: 33a are tightly held in position by endcovers 34: and. 35 and pieces 45. The end covers are concentric with the rotor since extensions 37 engage their interior surface at several points. Thiscondition assists greatly in balancing the rotor after construction.

As previously described, the large fan 4: is located external to frame 1, and blows air therein through holes 46. and part'of the circulation goes through vent plate 39- which plate, together-with wedge 41, secures the wind- It will be observed In cooling the machine that by placing the fan 4 external to the frame 1, a much larger diameter fan may be employed than one which is installed inside of frame 1.

In Figure 6, a complete coil section 47 is composed of two layers 48a and 48b of square wire. These layers are so wound that in each layer a continuous current introduced in the coil end or terminal 49a flows through the-two layers 48a and. 48b in the same clockwise direction, with the current leaving the terminal or coil end. 4% which is adjacent the coil end 49a.

In Figure 7 the first step in forming a coil section 47 may be observed. A reversible coil winding machine M includes a motor-driven shaft 70 projecting therefrom. A back-up plate 71 is secured on shaft 70 to'rotate therewith, and a generally rectangular shaped coil form 72 is placed flush against the back-up plate 71 and is likewise afiixed to shaft 70 to rotate therewith. The spool 73, referred to herein as a storage spool, is releasably attached to shaft 70 for turning therewith by nut which is threaded on shaft 70.

The first step in the winding process is to wind enough wire 74, i. e., a first portion of wire, from supply spool 75 onto storage spool 73. Supply spool 75 is turnably mounted on an axle 76 to permit wire 74 to be reeled out in a well-known manner. After storage spool 73' has received. the desired amount of wire stock 74, corresponding generally to the wire in one layer of the finished coil, the succeeding portion of wire, without cutting, is placed on form 72 so that upon further rotation R1 (in the same direction) of the form 72, the wire 74 supplied directly from spool 75 beginning at the center or intermediate point 50, builds up into a vertical layer 48a. When this layer has been formed to the desired height, the connection between layer 48a and supply spool 75 is cut so as to leave a free end 49a. There has now been formed one layer 48a progressing from a center point 50 to an external free end 49a at the top center of the layer.

The second stage of this coil forming process may be observed in Figure 8. With layer 48a still on the form 72, and without severing the connection between point SOand the wire originally stored on storage spool 73, the spool 73 is removed from shaft 70 and placed on a second axle 77 at the opposite side of the machine from spool 75 (which is now inactive). With spool 73 rotatable on axle 77 and with common point 50 of coil layer 48a and wire stock 74 resting on form 72, the rotation of machine M and consequently shaft 70 is reversed (as indicated by the arrow R2), so that a.sec and layer 48b is built up adjacent and parallel to layer 48a. When the second layer 48b is thus completed, it terminates at 4% adjacent free end 49a, or else it is cut to so terminate. It is seen from, this description taken in connection with Figure 6 that this process produces a coil section consisting of two layers of continuous wire in which a direct current, introduced for example at terminal 49a, travels in the same clockwise. direction in both coil layers 48a and 48b and that both layers have their free ends or terminals terminating adjacent each other. The completed coil section (two layers) 47 may now be removed from the machine and bound together with insulating tape as is customary in the construction of dynamo-electric windings. It is observed that when the storage spool 73 is mounted on shaft 70, its inner flange provides a backing plate for the flangeless coil form 72 complementary to the backing plate 71; and when the storage spool 73 is removed from shaft 70 for purposes described above, a suitable auxiliary backing plate (not shown) may be placed on the shaft 70 and indeed such auxiliary backing plate may comprise the flange of an auxiliary reel having dimensions like those of the storage reel 73.

Referring now to'the specific method of installing the finished windings on the rotor, the first step here is to form seven coil sections 47 of difierent lengths, but ofthe same width, as shown in Figure 4 as sections 47a-47g, both inclusive, by the method just described, using successively seven slightly difiertnt length coil forms 72, as indicated in Figure 11 by coil forms 72A-72G, both inclusive. The seven staggered lengths of coil sections 47, subsequently serially connected as shown in Figure to form a composite winding 33, are placed at the bottom of one winding slot to overlie the vent plate 39 therein. There are provided four of such composite windings, one for each winding slot. The free legs of these windings 33 comprising the progressively staggered legs 47a-47g, both inclusive, are then bent to follow generally the circumference 61 of the rotor as closely as possible. The free legs are then forced into the next adjacent rotor slot 32., so that when finally in position in overlying relationship to the next winding 33, the originally staggered legs of sections 47a-47g lie on a straight line which extends parallel with the plane of the wall 53 of slot 32. This construction employing square wire coil sections permits the maximum of copper to be installed in the slot and thereby increases the effectiveness of the magnetic flux created in the poles N and S. The separate windings 33 in the same slot are placed one over the other in a very compact arrangement so that current in all the coil sections 47 in one slot travel in the same circuitous direction. This installation has the additional advantage of keeping the end legs 33a of the windings as close as practical to the circumference 61 of the rotor so as to obtain the maximum density of the flux as near the stator as possible.

It should be noted that the number of turns of square wire are such that the resulting winding depth is equal to the rotor slot width, and that the free legs of each section becomes automatically staggered upon inserting the sections into the winding slot.

In Figures 5 and 10, the method of connecting individual coil sections 47 to form composite windings 33, and the method of connecting the composite windings, may be observed. The free ends or terminals 49a and 49b of the coil sections 47 for each composite winding 33 lie closely adjacent in a straight line. The coil sections 47 for a composite winding 33 are conveniently connected in series by short leads 54 which are soldered or otherwise connected between a terminal 4% of each coil section 47 and adjacent terminal 4% of the adjacent coil section. One end terminal of each of two adjacent composite windings is connected by a lead 52a, 52b, to the slip ring mechanism 6. The remaining end terminals of the composite windings are appropriately connected by leads 51 so that the composite windings form a conventional series field excitation circuit which may be energized through the slip ring mechanism from a direct current source.

From the foregoing description it will be readily seen that I have produced such a device as substantially fulfills the objects of the invention as set forth herein.

While this specification sets forth in detail the present and preferred construction of this invention, still in practice such deviations from such detail may be resorted to as do not form a departure from the spirit of the invention, as defined in the appended claims.

I claim:

1. In a method of forming two layer coil sections for a winding for a dynamo-electric machine involving: a coil Winding machine having a reversible shaft extending therefrom, a back-up plate, a coil form, a storage spool secured to said shaft outwardly of said back-up plate and form, a supply spool free-turning on an axle external to said machine, the steps comprising winding wire from said supply spool to said storage spool in sufficient length to form the second layer of said coil section, placing the wire from said coil section over said form, rotating said coil form in the same direction to build up the first layer of said coil section, cutting the wire from said supply spool to form one terminal of the coil section, removing the storage spool from said shaft and placing the same on another independent axle, reversing the direction of rotation of said form so as to build up a second vertical layer adjacent to and parallel to said first layer, the end of said second layer ending at a point adjacent to said one terminal to form a second terminal.

2. A method of forming two layer coil sections for a winding for a dynamo-electric machine involving a coil winding machine having a reversible shaft extending therefrom, a back-up plate secured to said shaft, a form placed flush against said back-up plate, a storage spool secured to said shaft outwardly of said back-up plate and form, a supply spool free-turning on an axle external to said machine, the steps comprising winding wire from said supply spool onto first storage spool in sufficient length to form the second layer of said coil section, placing the wire from said coil section over said form, rotating said form in the same direction to build up the first layer of said coil section, cutting the wire from said supply spool to form one terminal of the coil section, removing the storage spool from said shaft and placing the same on another axle, reversing the rotation of said form so as to build up a second vertical layer adjacent to and parallel to said first layer, the end of said second layer ending at a point adjacent to said one terminal to form a second terminal, the coil section thus formed comprising two layers of continuous wire.

3. In a method for winding double layer coils in which some of the wire is initially wound on said storage spool from a supply spool and then onto a coil form, the steps comprising winding wire from said supply spool to said storage spool in an amount corresponding to a single layer of said double layer coil and until an intermediate portion of said wire is reached corresponding to an intermediate portion of the finished double layer coil, placing said intermediate portion on said coil form and rotating said coil form and said storage spool simultaneously to reel off an additional amount of said wire directly from said supply spool to said coil form with said coil form rotating in a first direction, until an amount of wire is wound on said coil form corresponding substantially to one layer of the finished coil, severing the wire on said coil from the wire on said supply spool, removing the storage spool and placing the same so that it may rotate independently of said coil form, rotating said coil form with respect to said storage spool in a direction opposite to said first direction to transfer the wire from said storage spool onto said coil form in a second layer disposed adjacent to the first layer.

4. In a method for winding double layer coils in which a portion of the wire comprising the finished coil is transferred first from a supply spool onto a storage spool and then onto a winding form, the steps comprising winding an initial portion of the wire from said supply spool onto said storage spool until an intermediate point on said wire is reached, then placing said intermediate point on said coil form, then rotating said storage spool and said coil form in unison in a first direction so as to transfer a succeeding portion of the wire directly from the supply spool onto said coil form, severing the connection between the wire on the coil form and the Wire on the supply spool, removing the storage spool and placing the same so that it may rotate independently of said coil form, and then rotating the coil form independently of said storage spool in a direction opposite to said first direction to transfer the wire from said storage spool onto said coil form.

5. In a method for winding a double layercoil involving a supply spool, a storage spool and a coil form, winding a first portion of wire from said supply spool directly onto said storage spool, winding a second portion of said wire from said supply spool directly onto said coil form while rotating said storage spool in unison with said coil form in a first direction and without severing the connection between said first portion and said secondportion, severing the connection between said second portion and the remaining portion of wire on said supply spool, removing the storage spool and placing the same so that it may rotate independently of. said coil form, then rotating said coil form independentlyv of said storage spool in a direction opposite to said first direction to transferv said first portion from said storage spool onto saicl'v coil form.

6. In a method for forming double layer coil forms involving a supply spool, a storage spool and a coil form, the steps comprising rotating said storage spool and said coil form about a common axis in unison and in the samedirection while transferring a first portion of wire from said supply spool onto said storage spool, transferring a second portion of the wire from said supply spool onto said coil form without severing the connection between said first portion and the wire on said supply spool, and with said coil form and said storage spool both rotating in said same direction, severing the connection between said second portion on said coil form and the remaining wire on said supply spool, removing the storage spool and placing the same so that it may rotate independently of said coil form, and thentransferring said first portion of wire onto said coil form with said coil form being rotated independently of said storage spooland'in a direction opposite to the aforementinned-same direction.

7. In an arrangement for forming double, layer coil forms, a first rotatable shaft, a first backing plate mounted on said shaft, for rotation therewith, a fiangeless coil shaft extending generally parallel with both said first and second shafts,v said. first shaft being intermediate said second and. thirdvshafts, and said third shaft being adapted to rotatablysupport said storage spool.

References Cited in the file of this patent UNITED STATES PATENTS 1,832,427 Roller Nov. 17, 1931' 2,243,837 Bugler -Q June 3, 1941 2,406,130 Boyce Aug. 20, 1946 2,479,391 Miller Aug. 16, 1949 FOREIGN PATENTS- 640,121 Germany Dec. 22, 1936 851,979 Germany Oct. 9, 1952,

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