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. .Iadd.

What I claim as new and desire to secure by Letters Patent of the United States is: 
     
       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 .Iadd.primary .Iaddend.winding arranged in a plurality of said slots and including at least .[.two.]. .Iadd.one first .Iaddend.coil .[.groups.]. .Iadd.for .Iaddend.defining .[.at least two.]. .Iadd.a .Iaddend.predetermined magnetic .[.poles.]. .Iadd.pole of a first instantaneous polarity, and at least one second coil for defining a predetermined magnetic pole of a second instantaneous polarity.Iaddend.;   .[.c..]. each of .[.said at least two.]. .Iadd.the .Iaddend.predetermined magnetic poles having a radial polar axis, with .[.said.].  .Iadd.the .Iaddend.radial polar axes being substantially angularly spaced apart around said core; and   .[.d. said at least two coil groups.]. .Iadd.the at least one first and second coils .Iaddend.being arranged generally concentrically about one of .[.said.]. .Iadd.the .Iaddend.radial polar axes .[.about an.]. .Iadd.and having portions thereof spanning an arcuate extent in excess of 180 electrical degrees and arranged .Iaddend.to leave a preselected polar region of said core in the vicinity of the other of .[.said.]. .Iadd.the .Iaddend.radial polar axes free of .[.said at least two coil groups.]. .Iadd.that at least one first and second coils.Iaddend..   
     
     
       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 .Iadd.primary .Iaddend.winding concentrically arranged in a plurality of said slots;   .[.c..]. said plurality of slots encompassing a first arcuate region of said core .[.,.]. .Iadd.in excess of 180 electrical degrees and .Iaddend.less than its circumference; and   .[.d..]. the end turns associated with said .Iadd.primary .Iaddend.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 .Iadd.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.Iaddend.. 
     
     
       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..]. .Iadd.a .Iaddend.distributed .Iadd.primary .Iaddend.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 .Iadd.and having an arcuate extent in excess of 180 electrical degrees.Iaddend.; 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 .Iadd.percent .Iaddend.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 .Iadd.primary .Iaddend.winding arranged in a plurality of said slots and including at least two coil groups defining at least two predetermined magnetic .Iadd.primary .Iaddend.poles; each of said at least two predetermined .Iadd.primary .Iaddend.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 .Iadd.along an arcuate region of the core having an arcuate extent in excess of 180 electrical degrees and also arranged .Iaddend.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.]. .Iadd.are .Iaddend.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. .Iadd. 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. .Iaddend. .Iadd. 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. .Iaddend..Iadd. 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. .Iaddend..Iadd. 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. .Iaddend. .Iadd. 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.