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The invention includes an electric machine having a rotor, stator and at least one winding in the stator adapted to conduct a current, and a secondary winding, electrically isolated from the first winding and inductively coupled to the first winding, which may be used to control at least one of the

The invention includes an electric machine having a rotor, stator and at least one winding in the stator adapted to conduct a current, and a secondary winding, electrically isolated from the first winding and inductively coupled to the first winding, which may be used to control at least one of the output voltage and current of the first winding.

대표청구항 ▼

1. An electric machine operable as an alternator, the machine comprising:a permanent magnet rotor mounted for rotation about an axis; a stator adjacent the rotor, the stator including a plurality of radial slots defined in the stator between pairs of teeth, and a magnetically conductive bridge mount

1. An electric machine operable as an alternator, the machine comprising:a permanent magnet rotor mounted for rotation about an axis; a stator adjacent the rotor, the stator including a plurality of radial slots defined in the stator between pairs of teeth, and a magnetically conductive bridge mounted to the stator in at least one of the slots and extending between a pair of said teeth defining the at least one slot, the bridge dividing the at least one slot into at least two slot portions; a first winding forming at least a portion of a first circuit, the first circuit adapted to deliver generated electricity from the machine, the first winding having a loop portion including at least a first leg and a second leg, the loop portion disposed in the at least one slot such that the first leg is disposed in a first one of said at least two slot portions and adjacent a first side of the bridge, and the second leg is disposed in a second of said at least two slot portions and adjacent a second side of the bridge, the first and second sides of the bridge opposing one another; and a second winding forming at least a portion of a second circuit, the second circuit electrically isolated from the first circuit, the second winding disposed in the stator adjacent the second leg of the first winding. 2. The electric machine of claim 1 wherein the second winding is disposed in the at least one slot in the second one of the at least two slot portions and wherein the second winding is adjacent the second side of the bridge.3. The electric machine of claim 1 wherein the bridge and said pair of teeth defining the at least one slot together form a portion of at least two magnetic circuits in the stator.4. The electric machine of claim 1 wherein the fist one of said at least two slot portions is radially closer to the rotor than the second one of said at least two slot portions.5. The electric machine of claim 1 wherein the stator has a rotor face adjacent the rotor and wherein the plurality of radial slots are defined in the rotor face.6. The electric machine of claim 1 wherein the second one of said at least two slot portions is remote from a rotor magnetic circuit.7. The electric machine of claim 1 wherein said pair of teeth defining the at least one slot are immediately adjacent to one another in the stator.8. The electric machine of claim 1 wherein the second winding is connected to a control circuit.9. The electric machine of claim 1 wherein the second winding is includes a current-limiting member.10. The electric machine of claim 1 wherein the rotor is a brushless rotor.11. The electric machine of claim 1 wherein the bridge is at least partially comprised of a low Curie point material.12. The electric machine of claim 11 wherein the bridge is made at least partially of ferrite.13. An electric machine operable as an alternator, the machine comprising:a rotatable permanent magnet rotor; and a stator assembly mounted adjacent the rotor assembly, the stator assembly including a plurality of openings including a first opening and a second opening, the first and second openings being separated by a portion of the stator assembly, a first electrical winding electrically connected to a first circuit, the first circuit adapted to provide electricity output from the machine when the machine is operated as an alternator, the first electrical winding disposed at least partially in the first opening and at least partially in the second opening so as to at least partially form a loop, and a second electrical winding connected to a second circuit, the second electrical winding electrically isolated from the first electrical winding the second winding disposed in the second opening adjacent the first winding, wherein said portion of the stator assembly defines a portion of at least two magnetic circuit paths in the stator assembly for guiding magnetic flux generated as a result of the rotor rotating about the stator, and wherein a first one of said at least two magnetic circuit paths at least partially encircles the first opening and first winding therein, and wherein a second one of said at least two magnetic circuits at least partially encircles the second opening and the first and second windings therein, and wherein the secondary magnetic circuit is defined entirely within the stator assembly. 14. The electric machine of claim 13 wherein the first electrical winding loop wraps substantially around the portion of the stator assembly separating the first and second openings.15. The electric machine of claim 13 wherein the first opening is radially closer to the rotor than the second opening.16. The electric machine of claim 13 wherein the first and second electrical windings are inductively coupled to one another and wherein the second electrical winding is inductively isolated from the rotor.17. The electric machine of claim 13 wherein when the rotor is rotated about the stator assembly a magnetic flux circulating about the first one of said at least two magnetic circuits causes a magnetic flux to circulate about the second one of said at least two magnetic circuits.18. A permanent magnet machine operable as an alternator, the machine comprising:a rotatable rotor; at least a first winding electrically connected to a machine output adapted to deliver generated output electricity from the machine when the machine is operated as an alternator; at least a second winding including a current-limiting device, the second winding electrically isolated from the first; and a stator adjacent the rotor, the stator defining at least a first opening and a second opening, the first winding disposed in the first opening and second opening, the second winding disposed only in the second opening, the stator and rotor together defining a primary magnetic circuit path around the first opening, whereby relative movement between the rotor and the stator causes a primary magnetic flux to flow around the primary magnetic circuit path which thereby induces a voltage across the first winding and an associated current flow in the first winding, the stator also defining a secondary magnetic circuit within the stator around the second opening, the first and second windings being disposed in the first and second openings and the first and second openings being positioned in the stator such that, in use, said voltage and current induced in the first winding induces a secondary voltage and an associated current flow in the second winding, wherein the current-limiting device is adapted to prevent a current flow in the secondary winding when a pre-selected threshold current in the secondary winding is exceeded, the second winding thereby limiting a maximum current flow in the first winding to at least a desired maximum current flow limit. 19. The permanent magnet machine of claim 18 wherein said current flow in the first winding at least partially provides an output current of the machine.20. A permanent magnet machine wherein the current-limiting device open-circuits the second winding when a pre-selected threshold current in the secondary winding is exceeded.21. A permanent magnet machine operable as an alternator, the machine comprising:a rotor having a plurality of permanent magnetic poles; a first winding electrically connected to a machine output, the output adapted to deliver generated output electricity from the machine; a second winding including a current-limiting device; and a stator adjacent the rotor, the first and second windings disposed in the stator, the stator and rotor together defining a first magnetic circuit around a portion of the first winding, the stator defining a second magnetic circuit within the stator around a portion of the first and second windings, wherein the first and second windings are inductively coupled such that, in use, a voltage and current induced in the first winding by rotation of the rotor induces a secondary voltage and a current flow in the second winding, and wherein when a pro-selected threshold current is exceeded in the second winding, the current-limiting device prevents current flowing through the secondary winding, thereby limiting a maximum current flow in the first winding. 22. A permanent magnet machine operable as an alternator, the machine comprising:a rotor having a plurality of permanent magnetic poles; a stator adjacent the rotor, the stator including at least a first winding disposed in at least one slot in the stator and a transformer disposed in the stator, the first winding inductively coupled to the rotor such that rotation of the rotor induces an output voltage and current in the first winding, the transformer electrically connected to the first winding and adapted to control at least one of said output voltage and current of the first winding. 23. The permanent magnet machine of claim 22 wherein the transformer has at least a primary and a secondary winding, and wherein the primary winding is a portion of the first winding.24. An electric machine operable as an alternator, the machine comprising:a stator; a permanent magnet rotor opposing the stator; and at least two windings disposed in the stator and electrically isolated from one another, wherein a first of the at least two windings comprises a primary winding in the stator for at least one of producing and consuming power, and wherein rotation of the rotor induces an output voltage and current in the primary winding, and wherein a second of the at least two windings comprises a secondary winding in the stator, the secondary winding being arranged and disposed in the stator adjacent a portion of the primary winding such that sad induced current in the primary winding induces at least a voltage across the secondary winding, and wherein the secondary winding is inductively coupled substantially only to the primary winding and is inductively isolated from the rotor, and wherein the electric machine further includes means for controlling current flow in the secondary winding, said means adapted to thereby affect current flow in the primary winding. 25. A permanent magnet machine operable as an alternator, the machine comprising:a rotor having a plurality of permanent magnetic poles; a stator adjacent the rotor, the stator having an electromagnetic core portion defining a plurality of radially extending teeth, at least one bridge portion extending between two adjacent teeth, a first winding wound around the core and wound around the at least one magnetically conductive bridge portion, and a second winding electrically isolated from the first winding and disposed in the stator adjacent the first winding, the second winding wrapped around the core portion but disposed remote from the bridge portion. 26. A permanent magnet machine according to claim 25 wherein the second winding includes a control member which, in use, is adapted to control a maximum current in the first winding.27. A permanent magnet machine according to claim 25 wherein the bridge separates the secondary winding from a portion of the first winding.28. A gas turbine engine comprising:a gas generator, the gas generator having a shaft adapted to output rotational power when the gas generator is operated, and an alternator drivingly connected to the shaft, the alternator including a permanent magnet rotor mounted for rotation about an axis; a stator adjacent the rotor, the stator including a plurality of radial slots defined in the stator between pairs of teeth, and a magnetically conductive budge mounted to the stator in at least one of the slots and extending between a pair of said teeth defining the at least one slot, the bridge dividing the at least one slot into at least two slot portions; a first winding forming at least a portion of a first circuit, the first circuit adapted to deliver generated electricity from the machine, the first winding having a loop portion including at least a first leg and a second leg, the loop portion disposed in the at least one slot such that the first leg is disposed in a first one of said at least two slot portions and adjacent a first side of the bridge, and the second leg is disposed in a second of said at least two slot portions and adjacent a second side of the bridge, the first and second sides of the bridge opposing one another; and a second winding forming at least a portion of a second circuit, the second circuit electrically isolated from the first circuit, the second winding disposed in the stator in the second slot portion adjacent the second leg of the first winding.