Magnetic commutation alternator, method of manufacture thereof and wireless infrastructure employing the same

• US 5,909,076 A
• Filed: 08/26/1997
• Issued: 06/01/1999
• Est. Priority Date: 08/26/1997
• Status: Expired due to Fees

• Current Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Original Assignee: Lucent Technologies, Inc. (Nokia Corporation)
• Inventors: Smith, William Craig
• Primary Examiner(s): Dougherty, Thomas M.
• Assistant Examiner(s): Lam, Thanh
• Application Number:
  US08/918,928
• Time in Patent Office: 644 Days
• Field of Search: 310/156, 310/177, 270/468, 323/48, 290/46
• US Class Current: 310/177
• CPC Class Codes: H02K 19/24 with variable-reluctance soft-iron rotors without winding

Abstract

Alternators employing magnetic commutation, methods of manufacturing the alternators and wireless communications infrastructures employing the alternators. In one embodiment, an alternator includes: (1) a stator having 4n alternating field and armature poles extending axially along and projecting from an inner surface thereof, n being a positive integer, the field poles having field windings disposed thereabout to form alternating North-South magnetic polar regions and the armature poles having armature windings disposed thereabout to allow conduction of electric power from the armature poles, (2) a rotor, disposed within and journalled for rotation relative to the stator, having 2n axial magnetic passive regions, each of the passive regions being of a circumferential width magnetically to bridge one of the armature poles and only one of the field poles and (3) an exciter, coupled to the stator, that provides a controlled level of DC excitation to the field poles to regulate an output of the alternator.

Claims

1. An alternator, comprising:

a stator having 4n alternating field and armature poles extending axially along and projecting from an inner surface thereof, n being a positive integer, said field poles having field windings disposed thereabout to form alternating North-South magnetic polar regions and said armature poles having armature windings disposed thereabout to allow conduction of electric power from said armature poles;

a rotor, disposed within and journalled for rotation relative to said stator, having 2n axial magnetic passive regions, each of said passive regions being of a circumferential width magnetically to bridge one of said armature poles and only one of said field poles; and

an exciter, coupled to said stator, that provides a controlled level of DC excitation to said field poles to regulate an output of said alternator.

2. The alternator as recited in claim 1 wherein said stator and said rotor are formed of pluralities of laminations.

3. The alternator as recited in claim 1 wherein said rotor comprises a nonmagnetic central section and at least two magnetic peripheral sections joined with said central section and forming said magnetic passive regions.

4. The alternator as recited in claim 1 wherein said stator and said rotor are divided longitudinally into m phase sections, m being a positive integer, said alternator being an m-phase alternator.

5. The alternator as recited in claim 1 wherein said rotor comprises a central section composed of a plastic material.

6. The alternator as recited in claim 1 wherein said rotor comprises a plurality of dovetailed sections.

7. The alternator as recited in claim 1 wherein said stator is composed of a magnetic material selected from the group consisting of:

a sintered magnetic material, and

a ferrite.

8. A method of manufacturing an alternator, comprising the steps of:

forming a stator having 4n alternating field and armature poles extending axially along and projecting from an inner surface thereof, n being a positive integer;

disposing field windings about said field poles to form alternating North-South magnetic polar regions;

disposing armature windings about said armature poles to allow conduction of electric power from said armature poles;

forming a rotor, disposable within and journalled for rotation relative to said stator, having 2n axial magnetic passive regions, each of said passive regions being of a circumferential width magnetically to bridge one of said armature poles and only one of said field poles; and

coupling an exciter to said stator to provide a controlled level of DC excitation to said field poles to regulate an output of said alternator.

9. The method as recited in claim 8 wherein said stator and said rotor are formed of pluralities of laminations.

10. The method as recited in claim 8 wherein said step of forming said rotor comprises the step of joining a nonmagnetic central section and at least two magnetic peripheral sections.

11. The method as recited in claim 8 wherein said stator and said rotor are divided longitudinally into m phase sections, m being a positive integer, said alternator being an m-phase alternator.

12. The method as recited in claim 8 wherein said step of forming said rotor comprises the step of molding a central section from a plastic material.

13. The method as recited in claim 8 wherein said step of forming said rotor comprises the step of joining a plurality of dovetailed sections.

14. The method as recited in claim 8 wherein said step of forming said stator comprises the step of forming said stator composed of a magnetic material selected from the group consisting of:

a sintered magnetic material, and

a ferrite.

15. A wireless infrastructure, comprising:

a plurality of mobile stations wirelessly couplable to effect wireless telecommunication therebetween;

a plurality of base stations, wirelessly couplable to ones of said plurality of mobile stations, that relay said wireless telecommunication between said mobile stations, each of said plurality of base stations having a battery back-up power source, said battery back-up power source having a battery and a generator-driven alternator for providing power to said battery, said alternator including;

a stator having 4n alternating field and armature poles extending axially along and projecting from an inner surface thereof, n being a positive integer, said field poles having field windings disposed thereabout to form alternating North-South magnetic polar regions and said armature poles having armature windings disposed thereabout to allow conduction of electric power from said armature poles;

a rotor, disposed within and journalled for rotation relative to said stator, having 2n axial magnetic passive regions, each of said passive regions being of a circumferential width magnetically to bridge one of said armature poles and only one of said field poles; and

an exciter, coupled to said stator, that provides a controlled level of DC excitation to said field poles to regulate an output of said alternator.

16. The infrastructure as recited in claim 15 wherein said stator and said rotor are formed of pluralities of laminations.

17. The infrastructure as recited in claim 15 wherein said rotor comprises a nonmagnetic central section and at least two magnetic peripheral sections joined with said central section and forming said magnetic passive regions.

18. The infrastructure as recited in claim 15 wherein said rotor comprises a central section composed of a plastic material.

19. The infrastructure as recited in claim 15 wherein said rotor comprises a plurality of dovetailed sections.

20. The infrastructure as recited in claim 15 wherein said stator is composed of a magnetic material selected from the group consisting of:

a sintered magnetic material, and

a ferrite.