System, method, and apparatus for stator and alternator for electric machine

1. A stator for an electric machine, comprising:

a generally cylindrical stator core having a plurality of circumferentially-spaced and axially-extending core teeth that define a plurality of circumferentially-spaced and axially-extending core slots in a surface thereof;

a main winding having a plurality of coils, each of the coils including a plurality of turns occupying the plurality of circumferentially-spaced and axially-extending core slots in the stator core; and

a tertiary excitation winding having a plurality of coils, each of the coils including a single turn occupying at least a subset of the plurality of circumferentially-spaced and axially-extending core slots in the stator core;

wherein the plurality of coils of the main winding is unevenly arranged in the plurality of circumferentially-spaced and axially-extending core slots; and

wherein at least 80% of the plurality of circumferentially-spaced and axially-extending core slots have an identical number of turns, wherein the turns are of the main winding and/or of the main winding and the tertiary excitation winding.

2. The stator of claim 1 , wherein:

a number of turns of the main winding occupying at least one of the plurality of circumferentially-spaced and axially-extending core slots is different from a number of turns of the main winding occupying at least another of the plurality of circumferentially-spaced and axially-extending core slots.

3. The stator of claim 2 , wherein:

every third slot of the plurality of circumferentially-spaced and axially-extending core slots has an additional turn of the main winding as compared to an adjacent and a next adjacent slot of the plurality of circumferentially-spaced and axially-extending core slots.

4. The stator of claim 3 , wherein:

the plurality of coils of the main winding occupies the plurality of circumferentially-spaced and axially-extending core slots of the stator core in a 5-5-6 turn pattern.

5. The stator of claim 4 , wherein:

the plurality of circumferentially-spaced and axially-extending core slots is 90 slots.

6. The stator of claim 5 , wherein:

the subset of the plurality of circumferentially-spaced and axially-extending core slots occupied by the single turn of the tertiary excitation winding is 20 slots; and

a filler material occupies 10 slots only of the plurality of circumferentially-spaced and axially-extending core slots.

7. The stator of claim 5 , wherein:

the main winding includes 60 5-turn coils and 30 6-turn coils.

8. The stator of claim 1 , wherein:

the electric machine is an alternator having one of a permanent magnet rotor or a salient-pole rotor, and includes 10 magnetic poles defining a plurality of pole pairs.

9. The stator of claim 1 , wherein every third slot of the plurality of circumferentially-spaced and axially-extending core slots has an additional turn of the main winding relative to an adjacent and a next adjacent slot of the plurality of circumferentially-spaced and axially-extending core slots.

10. An alternator for an electric machine, comprising:

a rotor having a plurality of magnets defining a plurality of pole pairs;

a stator having a plurality of circumferentially-spaced and axially-extending slots;

a main winding having a plurality of coils arranged in the plurality of circumferentially-spaced and axially-extending core slots; and

a tertiary excitation winding having a plurality of coils arranged in the plurality of circumferentially-spaced and axially-extending core slots;

wherein the plurality of coils of the main winding is not evenly arranged in the plurality of circumferentially-spaced and axially-extending core slots; and

wherein at least 80% of the plurality of circumferentially-spaced and axially-extending core slots have an identical number of turns, wherein the turns are of the main winding and/or of the main winding and the tertiary excitation winding.

11. The alternator of claim 10 , wherein:

the plurality of coils of the main winding each include a plurality of turns; and

the plurality of coils of the tertiary excitation winding each include a single turn.

12. The alternator of claim 11 , wherein:

a number of the plurality of turns of the main winding occupying at least one of the plurality of circumferentially-spaced and axially-extending core slots is different from a number of the plurality of turns of the main winding occupying at least another of the plurality of circumferentially-spaced and axially-extending core slots.

13. The alternator of claim 12 , wherein:

the plurality of coils of the main winding occupies the plurality of circumferentially-spaced and axially-extending core slots of the stator in a 5-5-6 turn pattern.

14. The alternator of claim 13 , wherein:

the plurality of circumferentially-spaced and axially-extending core slots is 90 slots; and

the plurality of magnets is 10 magnets defining five pole pairs.

15. The alternator of claim 14 , wherein:

the main winding includes 60 5-turn coils and 30 6-turn coils.

16. The alternator of claim 10 , wherein:

the plurality of coils of the main winding and the plurality of coils of the tertiary excitation winding occupy approximately 90% of a slot space defined by the plurality of circumferentially-spaced and axially-extending core slots.

17. The alternator of claim 10 , wherein:

a non-metallic filler material occupies a portion of not more than about 11% of the plurality of circumferentially-spaced and axially-extending core slots.

18. The alternator of claim 10 , wherein:

the electric machine is an off-highway vehicle, and the alternator is coupled to an engine of the off-highway vehicle.