CLAIMS
1. A separator for electrically separating groups of end windings in the stator of a rotating electrical machine, wherein the separator is arranged to provide a circumferential air channel through the windings.
2. A separator according to claim 1, wherein at least a portion of the separator is substantially planar, and the circumferential air channels are arranged in the plane of the separator.
3. A separator according to any of the preceding claims, wherein the separator comprises a substantially planar layer with a plurality of upright elements.
4. A separator according to claim 3, wherein the upright elements function to hold apart adjacent groups of windings.
5. A separator according to claim 3 or 4, wherein the circumferential air channel is provided between the upright elements.
6. A separator according to any of the preceding claims, wherein the separator comprises a plurality of circumferential air channels.
7. A separator according to any of the preceding claims, wherein the separator is configured to sit between two groups of end windings in the stator of a rotating electrical machine.
8. A separator according to any of the preceding claims, wherein the separator is arranged to deliver air flow to an area between two groups of windings which would not otherwise be exposed.
9. A separator according to any of the preceding claims, wherein the separator comprises at least one opening between the circumferential air channel and the windings.

10. A separator according to any of the preceding claims, wherein the separator is arranged to allow radial air flow through the windings.
11. A separator according to any of the preceding claims, wherein the separator is arranged to extend along substantially the length of a group of windings.
12. A separator according to any of the preceding claims, wherein the separator comprises a top layer and a bottom layer separated by an air gap.
13. A separator according to claim 12, wherein the circumferential air channel is between the top layer and the bottom layer.
14. A separator according to claim 12 or 13, wherein at least one of the top layer and the bottom layer comprises means for supporting a group of windings.
15. A separator according to claim 14, wherein the means for supporting a group of windings is arranged to reduce or prevent droop of the windings into the circumferential air channel.
16. A separator according to claim 14 or 15, wherein the means for supporting a group of windings comprises a series of planar elements.
17. A separator according to any of claims 12 to 16 wherein parts of the top layer are staggered with respect to parts of the bottom layer.
18. A separator according to any of claims 12 to 17, wherein a part of one layer is located opposite an opening in the other layer.
19. A separator according to any of claims 12 to 18, further comprising means for separating the top layer and the bottom layer.
20. A separator according to claim 19, wherein the means for separating is offset from the edge of a planar element for supporting a group of windings.

21. A separator according to any of claims 12 to 20, further comprising a sloping portion between the top layer and the bottom layer.
22. A separator according to claim 21, wherein the sloping portion comprises at least one slit.
23. A separator according to any of claims 12 to 22, wherein the separator comprises an area in which only one of the top layer and the bottom layer is provided.
24. A separator according to claim 23, wherein the area in which only one of the top layer and the bottom layer is provided comprises at least one hole.
25. A separator according to any of the preceding claims, the separator comprising a cut out area.
26. A separator according to any of the preceding claims, the separator comprising a planar portion and a curved portion.
27. A separator according to claim 26, wherein the planar portion comprises a plurality of ribs and a plurality of air holes therebetween.
28. A separator for separating end windings in the stator of an electrical machine, the separator comprising a planar portion and a curved portion, wherein the planar portion comprises a plurality of ribs and a plurality of air holes therebetween.
29. A separator according to any of claims 26 to 28, wherein the curved portion curves in a direction away from the plane of the planar portion.
30. A separator according to any of claims 26 to 29, wherein the planar portion is substantially tangential to the curved portion.

31. A separator according to any of claims 26 to 30, wherein the curved portion is arranged at least partially to conform to the shape of the end windings.
32. A separator according to any of claims 26 to 31, wherein the curved portion is arranged such that, in use, it curves around a group of end windings.
33. A separator according to any of claims 27 to 32, wherein the air holes are arranged in a grid pattern.
34. A separator according to any of claims 27 to 33, wherein the curved portion comprises air holes.
35. A separator according to any of claims 27 to 34, wherein the ribs are provided on an outer surface of the planar portion.
36. A separator according to any of claims 27 to 35, wherein at least some of the ribs define air channels.
37. A separator according to any of claims 27 to 36, wherein at least some of the ribs run in a direction substantially parallel to that of the end windings.
38. A separator according to claim 37, wherein the ribs provide a circumferential air channel through the machine.
39. A separator according to claim 37 or 38, wherein the ribs are provided on a region of the planar portion which, in use, is not directly in contact with the end windings.
40. A separator according to any of claims 27 to 39, wherein at least some of the ribs run in a direction substantially perpendicular to the windings.
41. A separator according to claim 40, wherein the ribs are provided on a region of the planar portion which, in use, is in contact with the end windings.

42. A separator according to claim 40 or 41 wherein the ribs are arranged to provide electrical separation between adjacent end windings.
43. A separator according to any of claims 27 to 42, wherein at least some of the ribs comprise slots.
44. A separator according to any of claims 26 to 43, wherein the planar portion has an end which is chamfered.
45. A separator according to any of claims 26 to 44, where the planar portion has at least one side which is chamfered.
46. A separator according to any of claims 26 to 45, wherein the curved portion is arranged to provide lacing support.
47. A separator according to any of the preceding claims, wherein the separator comprises two planar portions connected by a curved portion.
48. A separator according to claim 47, wherein the curved portion acts as a hinge.
49. A separator according to claim 47 or 48, wherein the separator is arranged at least partially to surround a group of end windings.
50. A separator according to any of claims 47 to 49, wherein the curved portion is curved through an angle of greater than 180°.
51. A separator according to any of claims 47 to 50, wherein the planar portions are angled towards each other as they extend away from the curved portion.
52. A separator according to any of claims 47 to 51, wherein the planar portions have ends which define an opening.

53. A separator according to claim 52, wherein the distance between the planar portions at the opening is less than a distance between the planar portions at a part of the separator away from the opening.
54. A separator according to claim 52 or 53, wherein the ends of the planar portions can be pushed apart.
55. A separator according to claim 54, wherein the separator returns to its original shape on removal of a force pushing the ends apart.
56. A separator according to any of claims 47 to 55, wherein the separator is arranged to grip a group of end windings.
57. A separator according to any of claims 47 to 56, wherein the curved portion is flexible.
58. A separator according to any of claims 47 to 57, wherein the curved portion comprises slots.
59. A separator according to any of the preceding claims, wherein the separator is substantially C-shaped in cross-section.
60. A separator according to any of the preceding claims, wherein the separator is in the form of a clip.
61. A separator for separating end windings in the stator of an electrical machine, wherein the separator is in the form of a clip arranged to be placed around the end windings, the separator comprising a plurality of air holes.
62. A separator according to any of the preceding claims, wherein the separator comprises a single planar portion.
63. A separator according to claim 62, wherein the separator comprises a curved portion which is curved through an angle of greater than 30° and/or less than 150°.

64. A separator according to any of the preceding claims, wherein the separator is arranged to separate end windings of different phases and/or at different electrical potentials.
65. A separator according to any of the preceding claims, wherein the separator is formed from an electrically-insulating material.
66. A stator according to any of the preceding claims, wherein the air holes and/or air channels provide resin drainage paths.
67. A stator according to claim 66, wherein the resin drainage paths facilitate resin drainage post stator impregnation.
68. A stator for an electrical machine, the stator comprising a plurality of groups of end windings and a separator according to any of the preceding claims.
69. A stator according to claim 68, wherein the stator is multi-phase, and the separator is arranged to separate groups of end windings of different phases.
70. A stator according to claim 68 or 69, wherein the air holes provide cooling of the end windings.
71. A stator according to any of claims 68 to 70, wherein the separator defines circumferential air channels which provide cooling of the end windings.
72. A method of providing electrical separation between groups of end windings of different phases in a stator of an electrical machine, the method comprising inserting a separator between groups of end windings, wherein the separator provides circumferential air channels through the windings.
73. A method of providing electrical separation between groups of end windings of different phases in a stator of an electrical machine, the method comprising inserting a separator between groups of end windings, the separator

comprising a planar portion and a curved portion, wherein the planar portion comprises a plurality of ribs and a plurality of air holes therebetween.
74. A separator substantially as described herein with reference to and as
illustrated in the accompanying drawings.
75. ' A method of providing electrical separation between end windings of
different phases in the stator of an electrical machine substantially as described
herein with reference to the accompanying drawings.