1. An excitation system for providing excitation to a main rotating electrical
machine, the excitation system comprising an exciter and an auxiliary generator,
5 wherein the exciter and the auxiliary generator have separate stator cores and share a common rotor core.
2. A system according to claim 1, wherein exciter rotor windings and auxiliary
generator poles are both provided on the common rotor core.
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3. A system according to claim 1 or 2, wherein one of the auxiliary generator
and the exciter is nested inside the other.
4. A system according to any of the preceding claims, wherein exciter rotor
15 windings are provided on a radially outwards side of the rotor core, and auxiliary
generator poles are provided on a radially inwards side of the rotor core.
5. A system according to claim 4, wherein the common rotor core comprises
slots on its radially outwards side for the exciter rotor windings.
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6. A system according to any of the preceding claims, wherein the exciter
comprises an exciter stator core and the auxiliary generator comprises an
auxiliary generator stator core.
25 7. A system according to claim 6, wherein the exciter stator core is located radially outwards of the common rotor core and the auxiliary generator stator core is located radially inwards of the common rotor core.
8. A system according to claim 6 or 7, wherein the exciter stator core, the
30 common rotor core and the auxiliary generator stator core are laminated.
9. A system according to claim 8, wherein a lamination for each of the exciter
stator core, the common rotor core and the auxiliary generator stator core is
punched from a concentric part of the same sheet of raw material.
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10. A system according to claim 8 or 9, wherein a lamination for the auxiliary
generator stator core is stamped from an area of raw material which is inside an
area from which the common rotor core is stamped, and a lamination for the
common rotor is stamped from an area of raw material which is inside an area
5 from which the exciter stator core is stamped.
11. A system according to any of claims 6 to 10, wherein at least one of the
exciter stator core and the auxiliary generator stator core is mounted on a
bracket.
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12. A system according to claim 11, wherein the bracket is for supporting a
shaft of the main machine.
13. A system according to claim 11 or 12, wherein the bracket comprises a
15 first set of mounts for mounting the exciter stator, and a second set of mounts for
mounting the auxiliary generator stator.
14. A system according to claim 13, wherein one set of mounts is located
radially inwards of the other set of mounts.
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15. A system according to claim 13 or 14, wherein at least one of the first set
of mounts and the second set of mounts is arranged in a substantially circular
configuration about a face of the bracket.
25 16. A system according to any of claims 11 to 15, wherein the bracket comprises ventilation holes.
17. A system according to claim 16, wherein the ventilation holes are provided
between adjacent mounts for mounting the exciter stator and/or wherein a
30 plurality of ventilation holes is provided spaced circumferentially about the bracket.
18. A system according to any of claims 12 to 17, wherein the bracket
comprises a mating face for mating with a frame of the electrical machine, a
35 bearing support member for supporting a bearing for the shaft of the main
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machine, and radial ribs extending between the mating face and the bearing support member.
19. A system according to claim 18, wherein the mounts for mounting the
5 exciter stator are co-located with the radial ribs, and ventilation holes are
provided between adjacent ribs.
20. A system according to any of claims 12 to 19, wherein the first set of
mounts and the second set of mounts are provided on the inward facing side of
10 the bracket.
21. A bracket for a rotating electrical machine, the bracket comprising a first
set of mounts for mounting an exciter stator, and a second set of mounts for
mounting an auxiliary generator stator, wherein the first set of mounts and the
15 second set of mounts are provided on an inward facing side of the bracket.
22. A system according to any of claims 1 to 20, further comprising a rotor
mount for connecting the common rotor core to a shaft of the machine.
20 23. A system according to claim 22, wherein the rotor mount comprises
means for mounting the common rotor core and/or means for connecting the rotor mount to the shaft of the machine.
24. A system according to claim 22 or 23, wherein at least one of the rotor
25 mount and the common rotor core comprises a protrusion which engages with a
recess in the other of the rotor mount and the common rotor core.
25. A system according to any of claims 22 to 24, wherein the rotor mount
comprises at least one axial channel for accommodating an electrical connection
30 between the exciter and the main machine.
26. A system according to any of claims 22 to 25, wherein the rotor mount
comprises means for mounting rotating diodes.
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27. A system according to any of the preceding claims, wherein the excitation
system comprises a fan.
28. A system according to any of claims 22 to 26, wherein the rotor mount
5 comprises a fan.
29. A rotor mount for connecting a rotating component of an excitation system
to a shaft of a main machine, the rotor mount comprising a fan.
10 30. A system or rotor mount according to claim 27 or 28, wherein the rotor mount comprises a first mounting member for connecting to the common rotor core, a second mounting member for connecting to the shaft of the main machine, and a plurality of fan blades which connect the first mounting member and the second mounting member.
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31. A system or rotor mount according to any of claims 22 to 26, 28 or 29, wherein the rotor mount comprises means for balancing rotating components of the machine.
20 32. A rotor mount for connecting a rotating component of an excitation system to a shaft of a main machine, the rotor mount comprising means for balancing rotating components of the machine.
33. A system or rotor mount according to claim 31 or 32, wherein the means
25 for balancing is a balance ring.
34. A system according to any of claims 1 to 20, 22 to 28, 30, 31 or 33,
wherein the common rotor core comprises at least one axial hole for
accommodating a wire from the exciter to the main machine.
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35. A system according to any of claims 1 to 20, 22 to 28, 30, 31, 33 or 34,
wherein the auxiliary generator is a permanent magnet generator.
36. A system according to claim 35, wherein the common rotor core
35 comprises slots for accommodating permanent magnets.
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37. A system according to claim 36, wherein a slot is formed on one side by a
recess in the common rotor core and on the other side by webbing on the
common rotor core.
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38. A system according to claim 37, wherein a plurality of slots is provided
within a single webbing.
39. A system according to claim 38, wherein the plurality of slots within a
10 single webbing accommodates magnets which form one pole of the permanent
magnet machine.
40. A system according to claim 38 or 39, wherein an airgap is provided in a
circumferential direction between adjacent slots within a webbing.
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41. A system according to any of claims 36 to 40, wherein the magnets of one
pole are arranged in at least one column, the column comprising at least one
magnet in an axial direction through a slot.
20 42. A system according to any of claims 36 to 41, wherein the slots are
arranged such that permanent magnets of the same size can be used in different configurations depending on the axial depth of the rotor core.
43. A permanent magnet generator for providing excitation to an exciter, the
25 permanent magnet generator comprising a rotor core with slots for
accommodating permanent magnets, wherein a plurality of slots is provided for the magnets of one pole, and the magnets of one pole are arranged in at least one column, the column comprising at least one magnet in an axial direction through a slot. 30
44. A system according to any of claims 35 to 42, wherein the permanent
magnet generator comprises a stator core with a plurality of salient poles, and
each of the poles is wound with a coil.
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45. A system according to any of claims 1 to 20, 22 to 28, 30, 31, 33 or 34,
wherein the auxiliary generator is a reluctance machine.
46. A rotating electrical machine comprising a main machine and an excitation
5 system according to any of claims 1 to 20, 22 to 28, 30, 31, 33 to 42, 44 or 45.
47. A rotating electrical machine according to claim 46 when dependent on
claim 11, wherein the excitation system is provided on the same side of the
bracket as the main machine.
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48. A rotating electrical machine according to claim 47, wherein the excitation
system is housed by a frame of the main machine, and the bracket.
49. A method of manufacturing an excitation system, the excitation system
15 comprising an exciter and an auxiliary generator, the method comprising
manufacturing the excitation system with separate stator cores and a common rotor core for the exciter and the auxiliary generator.
50. A method of mounting non-rotating components of an excitation system
20 for providing excitation to a main rotating electrical machine, the method
comprising mounting an exciter stator and an auxiliary generator stator on an inward facing side of a bracket for supporting a shaft of the rotating electrical machine.
25 51. A method of connecting a rotating component of an excitation system to a shaft of a main machine, the method comprising mounting the rotating component on a rotor mount comprising a plurality of fan blades.
52. A method of assembling a permanent magnet generator for providing 30 excitation to an exciter, the permanent magnet generator comprising a rotor core with slots for accommodating permanent magnets, wherein a plurality of slots is provided for the magnets of one pole, the method comprising arranging the magnets of one pole in at least one column, the column comprising at least one magnet in an axial direction through a slot. 35
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53. A method of balancing a rotating electrical machine comprising a main machine and an exciter, wherein the exciter comprises balancing means, the method comprising balancing rotating components of the machine by adjusting the weight of the balancing means.
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