Stator slot and winding arrangements

Abstract

A stator, for use in an alternating current motor, includes a core having a plurality of angularly spaced slots. A distributed main winding is concentrically arranged in a plurality of the slots, with these slots encompassing a first arcuate region of the core, less than its circumference. end turns for the main winding are positioned adjacent an end face of the first arcuate region of the core. This provides a second arcuate region of at least one end face of the core free of the main winding. In a first embodiment, an auxiliary winding, displaced in phase from the main winding, is received in a plurality of the slots, including at least some slots in the second arcuate region. In the first embodiment, end turns of the auxiliary winding in the second arcuate region are disposed inwardly of the radially outermost edges of the slots in the second arcuate region along at least one end face of the core. In a second embodiment, the second arcuate region of one end face of the core is free of both the auxiliary winding and the main winding.

Description

CROSS-REFERENCE TO RELATED APPLICATION

This is a continuation-in-part of my co-pending application Ser. No. 805,625 filed Mar. 10, 1969 and now abandoned. on, slots extend from both sides of a region 107 of the end face of the core 61 which is available for use with mounting structure. Each of the teeth 63 is provided with a generally equal arcuate width so that the various slots are evenly distributed about the periphery of the bore 65. As in the FIG. 1 exemplification, slot liners extending longitudinally through the core along the lateral surfaces of the slots may be used in order to protect the winding forming wires received in the slots from being injured by contact with the laminations forming the core.

A main or primary winding, generally indicated at 75, of the distributed type is received in the slots 68 and defines two magnetic poles with each of these poles having a radial polar axis, indicated by the dashed lines 69 and 70. More particularly, the main winding 75 includes two coil groups arranged concentrically about the polar axis 69. The first of these groups includes four coils 71, 72, 73, and 74 which are respectively received in the slots as illustrated in FIG. 3. The other coil group includes four coils 76, 77, 78, and 79 which are concentrically arranged in other ones of the slots on each side of the radial polar axis 69. Thus, the distributed winding 75 occupies and, in turn defines, a first arcuate region of the core encompassing the slots 68 and the slots 67. That is, the first arcuate region in this FIG. 3 exemplification extends from the slot accommodating one coil side of coil 79 through the radial polar axis 69 to another slot accommodating the other side of coil 79.

As indicated in FIG. 3, the end turns 81 for the distributed winding 75 are positioned adjacent an end face of this first arcuate region. Although the end turns at each end of the stator are disposed as indicated for the core end face shown in FIG. 3, it will be understood that for some mounting applications, it may be desirable to provide a region free of the distributed winding at only one end face of the core. Preferably, the preselected arcuate region should have an arcuate length of at least about 30 electrical degrees and in the exemplification, the region 107 has an arcuate length of about 60 electrical degrees.

Some of the slots, including the slots 67 are provided with a secondary or auxiliary winding, in the exemplification, the auxiliary winding being a start winding. The auxiliary winding comprises two coil groups generally indicated at 82 and 83. The coil group 83 includes individual coils 80, 84, 85, and 86; the sides of the coils being received in the slots 66 and 67 as shown in the drawing. Also, included in the coil group 83 is coil 80a which is a "backlash" winding, i.e., having turns wound in a direction opposite to that of the turns of coil 80. Similarly, the coil group 82 includes individual coils 91, 92, 93, and 95 wound in a first direction and "backlash" coil 91a. The end turns of the coils 80, 84, 85, 86, 91, 92, 93, and 95 are denoted by the reference numeral 102 whereas the end turns of the backlash coils 80a, 91a are denoted by the reference numeral 102a.

Thus, it will be appreciated that the auxiliary winding is concentrically wound on the core in a distributed manner and is shifted in phase approximately 90 electrical degrees from the distributed main winding 75. The auxiliary or secondary winding forms an additional pair of magnetic poles having radial polar axes indicated by the dashed lines 94, 96. Although the radial polar axes 94, 96 have been shown positioned at approximately 90 electrical degrees with respect to the polar axes 69, 70 for purposes of illustration, it will be understood that with the illustrated winding arrangement and coil turn distribution that follows, the polar axes 94 and 96 are actually disposed at other than 180° with respect to each other. In the following example of the coil turn distribution for a motor constructed according to the FIG. 3 exemplification, 0.0339 inch diameter copper wire was used to form the main winding 68 and 0.0159 inch diameter copper wire was used to form the auxiliary winding. Furthermore, the stator core 61 had an outer diameter of about 4.8 inches and a bore diameter of about 2.4 inches. The resistance of the main winding was about 4.19 ohms and the resistance of the auxiliary winding was about 15.2 ohms. The winding distribution of the specific exemplification was as follows:

Main Winding    Auxiliary Winding
Coil No.
No. of Turns
Coil No.  No. of Turns
______________________________________
71      26          80        94
72      50          84        32
73      52          85        23
74      53          86        19
76      53          91        94
77      52          92        32
78      50          93        23
79      26          95        19
80a      (34)  backlash
91a      (34)  backlash
______________________________________

In the exemplification, the turns of the winding were arranged to form two auxiliary magnetic poles having instantaneously opposite polarity and two main magnetic poles having instantaneously opposite polarity. The "backlash" windings 80a and 91a were provided to increase the total resistance of the auxiliary winding. A more thorough discussion of backlash winding applications where it is desirable to employ backlash windings is contained in Smith et al. patent application Ser. No. (G.E. docket 03-HM- 4135) 56,935 on July 21, 1970 filed concurrently herewith and assigned to the assignee of this application and which issued Jan. 4, 1972 as U.S. Patent 3,633,057.

It will be appreciated that the end turns associated with the coil groups 82, 83 are disposed generally inwardly of the radially outer edge of the slots 67 and thus allow space adjacent to the end face of the core 61 for the end turns of the winding 68. In other words, the depth of the slots 67 has been selected to enlarge the effective end face area about radial polar axis 69 that is available for accommodating the end turns of the winding 68.

The arcuate region 107 of the core 61, by being free of coil turns (including end turns in the exemplification), provides an area suitable for use in mounting the core to a supporting structure. Also provided in the region 107 are a pair of longitudinally extending passageways 104, 106 which may be used in conjunction with mounting bolts that may be used to secure the stator core 61 to the mounting structure.

Now viewing FIG. 1 together with FIG. 4, it will be seen that interwinding insulators 97 are provided for the same purpose as insulators 45 in the FIG. 1 exemplification. Furthermore, insulation wedges 98 are provided in a conventional manner for each slot opening adjacent the bore 65, to close the entrance of the slots and hold the windings therein.

As shown most clearly in FIG. 4, twine, illustrated at 103, may be used to lace together the end turns of the main and auxiliary windings and secure them together into a structurally unified mass as was done in the case of the exemplification of FIG. 1. As clearly revealed in FIG. 2 and FIG. 4, in both exemplifications, at least parts of the end turns of the auxiliary windings are conterminous with at least parts of the primary windings.

Although the arcuate region 107 in FIG. 3 and the generally corresponding region of core 11 in FIG. 1 have been illustrated as having an arcuate extent of approximately 60 electrical degrees, and the cores 11 and 61 have been illustrated as having a substantially circular outer periphery, it will be understood that the invention may be embodied in cores of different shapes and having slot configurations other than those illustrated herein. In addition, the arcuate regions for such cores, generally corresponding to the region 107 may have an arcuate extent that is more or less than the arcuate extent of region 107.

While I have shown and described what at present is are considered to be the preferred embodiments of my invention in accordance with the Patent Statutes, changes may be made in the illustrated embodiments without actually departing from the true spirit and scope of the invention. Although the invention has been illustrated and described in connection with specific exemplifications that are particularly useful in permanent split capacitor and single-phase, two-pole, resistance split-phase motor applications, it will be understood by those skilled in the art that my invention and the benefits derived therefrom may be incorporated in other types of stators having winding coil groups forming at least two poles. It also will be understood that for ease of description of the invention, "coil groups" has been used to refer to winding sections in place on a core without implication as to whether the windings are wound directly on the core or are first wound as one, two, or more coil groupings and then positioned on the core by any suitable method. I therefore intend to cover in the following claims all such equivalent variations as fall within the invention.

Claims

1. For use in an alternating current motor; a stator including:

a. a core of magnetic material having a plurality of substantially angularly spaced apart, coil-accommodating slots;

b. a distributed primary winding arranged in a plurality of said slots and including at least two one first coil groups for defining at least two a predetermined magnetic poles pole of a first instantaneous polarity, and at least one second coil for defining a predetermined magnetic pole of a second instantaneous polarity;

c. each of said at least two the predetermined magnetic poles having a radial polar axis, with said the radial polar axes being substantially angularly spaced apart around said core; and

d. said at least two coil groups the at least one first and second coils being arranged generally concentrically about one of said the radial polar axes about an and having portions thereof spanning an arcuate extent in excess of 180 electrical degrees and arranged to leave a preselected polar region of said core in the vicinity of the other of said the radial polar axes free of said at least two coil groups that at least one first and second coils.

2. The invention as set forth in claim 1 wherein said preselected polar region has an arcuate length of at least 30 electrical degrees.

3. The invention as set forth in claim 1 wherein said stator also includes an auxiliary winding arranged in a plurality of said slots displaced in phase from said distributed winding; at least some of the coils of said auxiliary winding being received in slots formed in said preselected polar region of said core; the end turns associated with said last named coils being substantially disposed inwardly of the radially outermost edges of said slots in said preselected polar region.

4. For use in an alternating current motor; a stator including:

a. a core of magnetic material having a plurality of substantially angularly spaced apart slots;

b. a distributed primary winding concentrically arranged in a plurality of said slots;

c. said plurality of slots encompassing a first arcuate region of said core , in excess of 180 electrical degrees and less than its circumference; and

d. the end turns associated with said primary distributed winding being positioned adjacent an end face of said first arcuate region of said core whereby a second arcuate region of said core is provided free of said winding.

5. The invention as set forth in claim 4 wherein said second arcuate region has an arcuate length of at least about 30 electrical degrees.

6. The invention as set forth in claim 4 wherein said stator also includes an auxiliary winding arranged in a plurality of said slots, including at least some slots in said second arcuate region of said core; end turns of said auxiliary winding in said second arcuate region of said core being substantially disposed inwardly of the radially outermost edges of the slots in said second arcuate region of said core and at least part of at least some of the end turns of the auxiliary winding being conterminous with portions of some of the end turns associated with said distributed primary winding.

7. For use in an alternating current motor; a stator including:

a. a core of magnetic material comprising a yoke and a rotor receiving bore;

b. said bore having an axis extending longitudinally of said yoke;

c. said yoke defining a plurality of angularly spaced-apart slots;

d. a plurality of adjacent ones of said slots extending a shorter radial distance from said axis than other of said slots, said plurality of adjacent ones of said slots being disposed in one arcuate region of said core;

e. a distributed primary winding concentrically arranged in other of said slots; the end turns associated with said distributed winding being positioned adjacent an end face of said core in another arcuate region of said core defined by said other slots and having an arcuate extent in excess of 180 electrical degrees; and

f. an auxiliary winding arranged in at least some of said slots, including said adjacent ones of said slots; and end turns associated with said auxiliary winding, in said one arcuate region, being substantially disposed inwardly of the radially outermost edges of said adjacent ones of said slots.

8. The invention as set forth in claim 7 in which both some coils of said distributed winding and some coils of said distributed winding and some coils of said auxiliary winding are received in the same ones of said other of said slots; said coils of said auxiliary winding being placed therein radially inwardly of said coils of said distributed winding.

9. The invention as set forth in claim 7 wherein said one arcuate region of said core has an arcuate length of at least about 30 electrical degrees.

10. The invention as set forth in claim 7 wherein each of said adjacent ones of said slots have radial depth of no more than about 37 percent of the radial depth of said one arcuate region of said core.

11. For use in an alternating current motor; a core of magnetic material having a plurality of substantially angularly spaced-apart, coil-accommodating slots; a first distributed primary winding arranged in a plurality of said slots and including at least two coil groups defining at least two predetermined magnetic primary poles; each of said at least two predetermined primary magnetic poles having a radial polar axis, with the radial polar axes being substantially angularly spaced apart around said core; and said at least two coil groups being arranged generally concentrically about one of said radial polar axes along an arcuate region of the core having an arcuate extent in excess of 180 electrical degrees and also arranged to leave a preselected polar region of said core in the vicinity of the other of said radial polar axes generally free of said at least two coil groups.

12. The invention as set forth in claim 11 wherein said preselected polar region has an arcuate length of at least 30 electrical degrees.

13. The invention as set forth in claim 11 in which the magnetic core has an axis of revolution for a rotor and at least one of said coil-accommodating slots extends a shorter radial distance from the revolution axis than other of said coil-accommodating slots, said at least one slot being disposed generally in another preselected polar region of said core; said first distributed winding having end turns positioned adjacent at least one end face of said core and being extended across and angularly beyond said preselected polar region.

14. The invention as set forth in claim 13 in which a second distributed winding is arranged in some of said slots, including said at least one slot; and end turns associated with said second distributed winding being are disposed generally inwardly of the radially outer edge of said at least one slot to allow space adjacent the at least one end face of the core for end turns of the first distributed winding.

15. A stator for use in an electric motor, the stator comprising a magnetic core having a plurality of angularly spaced apart coil accommodating slots; a main winding comprising at least two coil groups defining at least two spaced apart magnetic poles each having a radial polar axis, with each of the coil groups having end turn portions positioned adjacent at least one end face of the core; said end turn portions being arranged in a configuration adjacent the at least one end face of the core so as to extend generally adjacent to one another, so as to extend across a first one of the radial polar axes of said at least two coil groups, and so that none of said end turns of the at least two coil groups extend across a second one of the radial polar axes of said at least two coil groups whereby a first arcuate region of the at least one end face of the core is free of the end turn portions of the at least two coil groups; at least some of the end turns of some of said windings encompassing a first arcuate region of said core having an extent at least of 180 electrical degrees.

16. A stator for use in an electric motor, the stator comprising a magnetic core having a plurality of angularly spaced apart coil accommodating slots and a main winding comprising at least one coil group defining at least one magnetic pole having at least one radial polar axis; said main winding having end turn portions positioned adjacent at least one end face of the core and arranged in a configuration adjacent the at least one end face of the core so as to extend across the at least one radial polar axis and so as to have an arcuate extent in excess of 180 electrical degrees while another arcuate region of the at least one end face of the core is free of main winding end turn portions.

17. The stator of claim 16 further comprising an auxiliary winding having at least one coil group, and wherein at least portions of the auxiliary winding and portions of the main winding are disposed within a common core slot. 18. The stator of claim 16 wherein some of coil accommodating slots are of a first cross-sectional area, and at least one other coil accommodating slot is of a cross-sectional area that is from about 70 to about 75 percent of the first cross-sectional area; said stator further including an auxiliary winding having at least some portion thereof disposed in the at least one other coil accommodating slot.

19. For use in an alternating current motor; a stator including: a magnetic core having a plurality of angularly spaced apart coil accommodating slots, wherein the slots are of at least two different cross-sectional areas with the smallest of such slots being of a cross-sectional area that is at least 50 percent of the cross-sectional area of the largest of such slots; a distributed winding arranged in a plurality of the slots and including at least one coil group defining at least one predetermined magnetic pole; the at least one predetermined magnetic pole having at least one radial polar axis; said at least one coil group being arranged generally concentrically about the at least one radial polar axis to leave a preselected region of said core diametrically opposite said at least one radial polar axis free of the distributed winding; said stator also including an auxiliary winding having at least one coil arranged in a plurality of said slots displaced in phase from said distributed winding; at least a portion of the at least one coil of said auxiliary winding being received in the smallest of such slots in the core; said preselected region of said core diametrically opposite said at least one radial polar axis further being free of at least the largest of such slots.