AU616455B2 - Toroidally wound generator/motor - Google Patents

Description

'ti; 616455 o DATE 05/07/89 APPLN. ID 28048 89 PCT NUMBER PCT/US88/04232

PCT

AOJP DATE 27/07/89 INTERNATIONAL APPLICATION PUBLISHED UNDER THE PA rENT COOPERATION TREATY (PCT) (51) International Patent Classification 4 (11) International Publication Number: WO 89/ 05538 H02K 3/12, 15/085 Al (43) International Publication Date: 15 June 1989 (15.06.89) (21) International Application Number: PCT/US88/04232 (74) Agent: SCHUMANN, Michael, Merchant, Gould, Smith, Edell, Welter Schmidt, 3100 Norwest Cen- (22) International Filing Date: 28 November 1988 (28.11.88) ter, 90 South Seventh Street, Minneapolis, MN 55402

(US).

(31) Priority Application Numbers: 126,743 272,993 (81) Designated States: AT (European patent), AU, BE (European patent), CH (European patent), DE (Euro- (32) Priority Dates: 30 November 1987 (30.11.87) pean patent), FR (European patent), GB (European 22 November 1988 (22.11.88) patent), IT (European patent), JP, LU (European patent), NL (European patent), SE (European patent).

(33) Priority Country:

US

Published (71) Applicant: ONAN CORPORATION [US/US]; 1400 With international search report.

73rd Avenue Minneapolis, MN 55432 With amended claims.

(72) Inventors: GULBRANDSON, William, E. 15 White Way, Clear Lake, MN 55319 O'MALLEY, Gary, B. 7432 Bacon Drive, Fridley, MN 55342

(US).

(54) Title: TOROIDALLY WOUND GENERATOR/MOTOR i,

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,4;i (57) Abstract A method and apparatus for a toroidally-wounr core winding for use in electromechanical devices such as motors and generators. The stator core is slotted on its inner edge, so that each slot is ciapable of holding a plurality of windings.

The core is toroidally wound through the slots. Toroidal, slotted end caps having a substantially planar face connected to the winding core and a curved face opposite the substantially planar face.

WO 89/05538 PCT/US88/04232 TOROIDALLY WOUND GENERATOR/MOTOR Field of the Invention This invention relates to armature and field windings for electromechanical devices, and, more particularly, to a method of winding and apparatus for toroidally-wound armatures and fields.

Background of the Invention Electromechanical devices such as motors and generators include a stationary, wound core called a stator and a rotatable wound core called a rotor.

Typically for AC machines the stationary wound core is the armature. Typical generators or motors will utilize an annular or donut-shaped stator, shown in Fig. 2. A rotor is inserted in the bored center of the stator winding.

Fig. 2 shows a traditionally wound stator The stator has a core 12 which has an inner face 14, an outer face 16, a first side face 18 and a second side face (not visible from Fig. The stator core 12 also forms slots, 22, 24, 26 and 28 on the inner face 14.

These slots are typically capable of holding one or more conductors.

The winding of most modern-day stator cores is achieved by winding conductors such as conductor through a slot such as slot 22, across the first side face 18 of stator core 12, through a second slot such as slot 28, around the second side face 20 of the stator core, through either the same slot 22 or a different slot such as slot 24, around the first side face 18 of the stator core, and so on as shown in Fig. 2. Typical stator cores will have several conductor windings through each slot with a great deal of bulk on each side face 18 and 20 of the stator core. In an effort to minimize the amount of bulk of such windings and to put the windings in proper WO89/05538 PCT/US88/04232 WO 89/05538 PCT/US88/04232 1/ 2f

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r -2form, such windings are frequently manually pounded, shaped and laced.

Moreover, the windings outside the slot contribute nothing to the performance of the machine, but add material and decrease efficiency.

Generally, a toroidally-wound core for electromechanical devices, sometimes known as a Gramme wind'ng as shown in U.S. Pat. No. 218,520, as known. In a Gramme-type winding, the core of the stator is substantially farther away from the rotors than the stator core of windings such as that shown in Fig. 1. The Gramme-type winding was intended and used primarily for direct current (DC) power, but has been replaced even for DC power uses by devices wound as shown in Fig. 2.

Moreover, such prior art toroldal windings have disadvantages in that the windings may be unduly stressed at the corners formed by the winding core, which may include many laminations and have a substantial thickness.

Summary of the Invention In accordance with the present invention there is disclosed a method for winding a core for an electromechanical device having at least two poles, said method comprising the steps of: forming an annular winding core having a plurality of core 20 projections and slots, the core projections and slots being located on an inner face of the core such that the core projections and slots are substantially parallel to the radius of the core; connecting a toroldal end cap to at least one side of the annular core, said toroldal end cap having a first surface capable of substantially planar contact with the annular core, having a second surface opposite said first surface having a substantially curved portion, and having radial end cap projections and slots on its inner diameter corresponding to the core projections and slots located along the inner diameter of the annular core such that the toroidal end cap projections and slots are aligned with the core projections and slots when said end cap is connected to said core; and torodally winding at least one conductor for each pole around the annular winding core in a direction substantially parallel to the annular core radius and around the curved portion of the toroldal end cap such that each conductor wound around said core is located in said toroidal end cap slots and the corresponding core slots of the annular winding core.

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ii WQ 89/05538 PCT/US88/04232 Brief Description of the Drawins Fig. 1 is a drawing of a toroidally-wound slotted stator in accordance with the present invention.

Fig. 2 is a drawing of a prior art traditionally wound stator in general use for electromechanical devices.

Fig. 3 is a close-up view of an electromechanical device in accordance with the present invention.

Fig. 4 is a front view of a core having an end cap showing a portion of the radial slots formed therein in accordance with the present invention.

Fig. 5 is a cross-sectional view of a portion of a core having an end cap in accordance with the present invention along the line 5-5' in Figure 4.

Fig. 6 is a cross-sectional view of a portion of a core having an end cap in accordance with the invention along the line 6-6' in Figure 4.

Detailed Description of the Drawings Fig. 1 shows a winding of a stator for an electromechanical device in accordance with the present invention. The wound stator 40 includes an annular or donut-shaped stator core 44. This core has an inner face 46, an outer face 62, a front face 60 and a back face 64 (not visible). Typically, the core is formed by stacking a series of laminations having substantially similar, toroidal faces to a desired thickness. In part to obtain faces 46, 60, 62 and 64 which are as smooth and flat as 4 possible, and in part so that the slots 48 (including slots 50, 52 and 54) are properly formed, the laminations are aligned with each other. The inner face 46 of the Istator core forms a boring, in which the rotor is placed. ^J This inner face 46 forms a number of slots around the inner circumference of the stator core, including slots 50, 52, and 54. A typical number of slots which may be IK formed on the inner edge of the stator core is 66, of V which 44 may be used to receive the primary windings in a

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WO 89/05538 PCT/US88/04232 two-pole device. The number of slots may vary and 66 is a number presented by way of example only.

The stator core as shown in Fig. 1 is wound as follows: A conductor winding 70 is wound through one of the slots located on the front face of the core, such as slot 50, around the back face of the stator core 64 in Fig. 1, around the outer face of the stator core 62, around the front face of the stator core 60, and back through an inner face slot. The conductor may be wound either through the same slot through which the previous winding was wound, in this case slot 50, or through an adjacent slot, such as slot 52. In the embodiment shown in Figs. 1 and 3, each winding of the conductor will typically be substantially parallel to the adjacent windings of the conductor along each face 46, 60, 62 and 64 of the stator core. The slots may also be skewed from the radial direction without deviating from the spirit of the invention. In the preferred embodiment, as shown in Fig. 1, two conductors, 70 and 72, will be wound around the largest portion of the stator core 44, as for a twopole device. In the embodiment shown, two additional i conductors 76 and 78 are wound around small portions of the stator core at locations opposite each other to i provide, for example, a secondary power source. This winding procedure as described in this and the preceding paragraphs may be described as toroidal winding.

As shown in Fig. 1, as conductors 70 and 72 are wound around the outer face 62 of the stator core, the conductors are exposed to the air. The lesser length of the wire needed in Fig. 1, as opposed to the length of wire needed using a winding such as the winding shown in Fig. 2, is evident from comparing the two figures. In Fig. 2, for a two-pole device, some windings will go nearly 180° around the stator core, for example from slots 32 to slot 34. One loop through these two slots would require a conductor of a length of approximately (2 where r equals the radius of the inner edge of the i WQ 89/05538 PCT/US88/04232 stator core and d equals the distance from the front to the back faces of the stator core. In contrast, each turn of the winding in accordance with the present invention will have a length approximately equal to the sum of the lengths of each face of the stator core 46, 60, 62 and 64.

Since, for most stator cores, the length of front and back faces 60 and 64 will be substantially less than 2 times the inner radius of the stator core, substantial reductions in the length of the conductors needed for a two-pole device may be achieved. The use of a shorter conductor also results in less resistance loss. Hence, the machine uses less material and has higher efficiency.

Such efficiencies may also be achieved for devices having more than two poles, although the improvement in efficiency will be reduced. The two-pole winding is presented herein by way of example only.

Figures 4, 5, and 6 show an alternate embodiment of a winding core 40' in accordance with the present invention having an end cap 100 shown on the face corresponding to front face 60 in Fig. 1. Typically, the core will have a similar end cap on its opposite face, corresponding to face 64 (not shown). The end cap will typically be constructed of plastic or other material capable of being molded into the shape shown. The bottom face of the end cap 102 will be capable of providing a substantially planar surface for contact with the laminated winding core. The end cap is comprised of a substantially toroidal section 110 corresponding to the substantially toroidal portion of the laminated winding core. Toroidal end cap portion 110 has projecting members 114 projecting towards the center of the end cap toroid.

Projecting members 114 are positioned such that each one aligns over laminated core projections 56 and 58 shown in Figures 1 and Fig. 4 shows a portion of the core with five windings 210 of conductor 70 inserted in slot 212.

Figure 4 also shows sets of terminals 120, 130, Y

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1 :4- 1 f 'ii ~I WO 89/05538 PCT/US88/04232 6 132, and 134 at locations which in the preferred embodiment correspond to the portion of the core adjacent to the beginning and end of each of the windings to be wound on the core. These beginning and ending points r typically correspond to areas adjacent to projections 82', 84' and 86' from the laminated winding core. Each set of terminals 120, 132, and 134 will typically include a terminal 122 for receiving one end of a winding extending from projection 80' to projection 86', a second terminal 124 for receiving one end of a first winding extending from projection 82' to projection 80', and a third terminal 126 for receiving one end of a second winding extending from projection 82' to projection On one of the two end caps typically used with the winding core, terminals such as terminals 122 and 124 will receive metal contacts for electrically connecting the windings to the generator or motor 'circuit, or to various other circuits such as power or charging circuits.

The other end cap of the winding core typically will not have metal contacts, but the terminals themselves may be used as spacers to hold the wound or unwound core on a planar surface such that any windings around the core will not directly contact the planar surface, avoiding damage to the windings. Sets of terminals 130, 132 and 134 will be similar to terminal set 120.

In the preferred embodiment shown in Fig. 4, each terminal set 120, 130, 132 and 134 is positioned adjacent to winding end projections 140, 142, 144 and 146, j respectively. These projections differ from projections i 114 in that the slots formed in projections 140, 142, 144, and 146 are wider and shallower than slots 114. Since the windings terminate in the vicinity of the terminal projectior.s 140, 142, 144 and 146, narrow, deep slots such as slots 114 are not needed. The laminated winding core may have relatively shallower slots at positions corresponding to terminal projections 140, 142, 144 and I 146 to facilitate alignment of the end caps with the Ii WQ 89/05538 PCT/US88/04232 laminated core.

Figures 5 and 6 shows cross-sectional views of Figure 4 along lines 5-5' and 6-6' in Fig. 4. The left side of Fig. 5 shows end cap 100 having a surface 102 capable of substantially planar contact with laminated core 150. End cap 100 is secured to laminated core 150 through securing means such as a triangular projection 160 integrated with end cap 100 and having a surface 162 which secures the end cap to laminated core 150, as shown in Fig. 6. A multiple number of such projecting securing members may be used. Terminal projecting members 142, 144 and 146 will typically be located above the securing means in the preferred embodiment. With the securing means comprised of projections as shown in Fig. 6, the end caps may be snapped onto the laminated core.

Fig. 5 also shows projection 114 and the inner surface of the slot to one side of projection 114, designated 172. Projection 114 is typically in an inverted-V shape. This inverted-V shape helps to guide the windings into the slots formed by the end cap and the corresponding slots of the laminated core. Fig. 6 shows a cross-section of terminals 122 and 124, previously described. The terminal projection 140 of laminated core 150 is circumscribed in part by inward projection 190 and the inner surface of the terminal projection, 180. The slot in the laminated core corresponding to the slot in the end cap shown in Fig. 6 is formed by projection 190' and inner surface 180'. As shown in Fig.

4, the inner surface of the end cap slot 180 is shorter than surface 172, since a full width slot is shown at surface 172 whereas a terminal end cap projection surfacei i" is shown at 180. Fig. 4 also shows five winding turns 210 i~ y| positioned in the slot 212 formed by the laminated core and the end cap. The turns are wound around the top, j toroidal portion of the end cap 110. The curved form of t end cap top portion 110 helps relieve stress on the til i^ WO 89/05538 PCT/US88/04232 8 windings, which generally do not overlap on the upper surface of the end cap.

End cap 100 also has recesses 212, 214, 216 and 218 which align with laminated core projections 80', 82', 84' and 86'. These recesses conform to the shape of the laminated core projections. These recesses are shaped for clamping the winding core to a winding machine. Each recess includes a curved fence portion to prevent the resin coating applied to the windings from contacting core projections 80', 82', 84' and 86'.

An insulating coating 220, such as a 3M Scotchcast 5230 brand powder coating, coats the metal laminated core. This powder coating is preferable to paper or other insulating materials bechuse the coating material is much thinner than these alternatives, enabling use of relatively narrow slots 114 in Fig. The use of relatively narrow, elongated slots results in the windings being positionzd substantially along a radial line corresponding to the radius of the toroid, the positioning shown in Fig. 4 at 210. The use of a relatively large number of relatively narrow slots accompanied by radial winding provides for improved cooling of the conductors in that more of the conductor L surface contacts the core, helping to dissipate more heat.

The slots will typically have a width greater than the width of the conductor to be wound in the slot and less than twice the width of the conductor to facilitate the radial winding. ii As shown in Figs. 3 and 4, the slots may be rounded at the bottom, but such rounding is meant to be included within the term "substantially rectangular." I 1 Through the use of slots, projections 56, 58 as 1 shown in Fig. 3, 114 in Fig. 4) minimize the air gapi between the stator core and the rotor used in combination with the wound stator. The efficiency of the device is improved thereby.

As shown in Fig. 3, each winding of each I WO089/05538 PCT/US88/04232 conductor 70, 72, 76 and 78 follows a virtually identical winding pattern around the stator core and along the radius of the stator ring. A similar pattern is shown in Fig. 4 at 210. The winding process may be easily automated for such a winding method, for example, by use of a digital winding machine. Typically, the windings for one pole oppose the direction of winding the opposing pole.

It should be considered as within the spirit of the disclosed device that a toroidal winding as shown could also be used for a rotor, although the invention is described herein in terms of a stator.

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Claims (16)

1. A method for w'nding a core for an electromechanical device having at least two poles, said method comprising the steps of: forming an annular winding core having a plurality of core projections and slots, the core projections and slots being located on an inner face of the core such that the core projections and slots are substantially parallel to the radius of the core; connecting a toroidal end cap to at least one side of the annular core, said toroidal end cap having a first surface capable of substantially planar contact with the annular core, having a second surface opposite said first surface having a substantially curved portion, and having radial end cap projections and slots on Its inner diameter corresponding to the core projections and slots located along the inner diameter of the annular core such that the toroidal end cap projections and slots are aligned with the core projections and slots when said end cap is connected to said core; and toroidally winding at least one conductor for each pole around the annular winding core in a direction substantially parallel to the annular core radius and around the curved portion of the toroidal end cap such that each conductor wound around said core Is located in said toroidal end cap slots and the corresponding core slots of Ihe annular winding core.

2. A method according to claim 1, wherein a first and second toroidal end cap are connected to said annular core, said first end cap connected to one side of said annular core and said second end cap connected to the other side of said annular core.

3. A method according to claim 2, wherein said toroidally winding step further comprises the steps of: toroidally winding at least one conductor for each pole through a first slot of the annular core, a first slot of the toroidal end cap corresponding to said first slot of the annular core, around the curved portion of the first end cap, around the outer diameter surface of the annular core, around the curved portion of the second end cap, and through a slot formed in the second end cap corresponding to said first slot of the annular core; and toroidally winding said conductor through successive slots formed in the annular core and the first and second end caps In a manner 1300o iI Ui vij 5 V. If iP similar to the manner of toroldally winding said conductor through said first slot of the annular core and the first and second end caps.

4. A method as claimed In claim 2, wherein the circumferential arc encompassed by each projection and each slot formed in the annular core and first and second end caps is substantially similar to the width of the conductor to be wound in said slot. A method as claimed in any one of the preceding claims, wherein the slots formed in the annular core and the end caps have a width approximately equal to the width of the conductor.

6. A method as claimed in any one of the preceding claims, wherein the step of toroidally winding a conductor through a first slot comprises winding a conductor a multiple number of times through said first slot such that the multiple windings within each slot are positioned in a substantially radial line. 7 A method as claimed in claim 6, wherein the number of windings Sin each slot is approximately

8. A method as claimed in any one of the preceding claims, wherein the projections formed in the toroidal end cap are wider at the surface which interfaces with the annular core than at the surface of the projection opposite the surface which interfaces the annular core.

9. A method as claimed in any one of the preceding claims, wherein the toroidal end cap projections are formed in a shape ;j substantially similar to an inverted V. 4 A method as claimed in any one of the preceding claims, wherein said toroidal end cap is formed to provide a substantially smooth I path for a conductor toroidally wound around said toroidal end cap.

11. A method as claimed in any one of the preceding claims, wherein each conductor is wound such that its windings do not overlap on an outer face of the core.

12. A method as claimed in any one of the preceding claims, wherein the core is wound such that a substantial portion of the surface area of each wding of each conductor is exposed to the surrounding environment on the outer face of the core.

13. A method as claimed in any one of the preceding claims, wherein the slots formed on the inner face of the core are substantially rectangular in shape. Zo X L. -nb 12

14. A method as claimed in claim 13, wherein the slots formed on the inner face of the core have a width greater than the width of the conductor and less than twice the width of the conductor. A method as claimed in :ny one of the preceding claims, wherein the annular winding core is comprised of slotted core laminations.

16. A method as claimed in any one of the preceding claims, wherein at least one of the toroidally wound conductors is wound in a direction opposite from at least one other toroidally wound conductor.

17. A wound core produced by the method of claim 1, wherein substantially all slots formed in the annular winding core are separated by an arc of approximately 5.5 degrees.

18. A wound core produced by the method of claim 1 comprising: an annular winding core forming a plurality of core projections and slots substantially parallel to an annular radius of said core, said core projections and slots located on the inner face of said core, the slots having a width substantially similar to the width of a conductor to be inserted in said slots; and a toroidal end cap connected to one side of said annular winding core and having a first surface planarally interfacing with said annular winding core, having toroidal end cap projections, having a second substantially curved side opposite said first surface, and forming toroidal end cap slots substantially corresponding to the core projections and slots such that the toroidal end cap projections and i slots are aligned with the core projections and slots when said end cap i is connected to said core.

19. A wound core produced by the method as claimed in any one of claims 1 to 16. A method for winding a core substantially as described herein with reference to Figs. 1, 3, 4, 5 and 6 of the drawings. f

21. A wound core substantially as described herein with reference to Figs. 1, 3, 4, 5 and 6 of the drawings. DATED this FIFTEENTH day of AUGUST 1991 Onan Corporation i Patent Attorneys for the Applicant SPRUSON FERGUSON 300o i s .1 im o