Downhole torque-generating and generator combination apparatus

• US 7,141,901 B2
• Filed: 05/01/2002
• Issued: 11/28/2006
• Est. Priority Date: 05/05/2001
• Status: Expired due to Term

• Current Assignee: Turbine Dynamics Limited
• Original Assignee: Gregson William Martin Spring
• Inventors: Spring, Gregson William Martin
• Primary Examiner(s): Nguyen, Tran
• Assistant Examiner(s): PRESTON, ERIK D
• Application Number:
  US10/476,435
• Publication Number:
  US 20040144570A1
• Time in Patent Office: 1,672 Days
• Field of Search: 310/113, 310/76, 310/77, 310/112, 310 92- 95, 175/104
• US Class Current: 310/77
• CPC Class Codes: E21B 4/04 Electric drives E21B4/12 takes precedence
• CPC Class Codes: E21B 41/0085 Adaptations of electric power generating means for use in boreholes
• CPC Class Codes: E21B 7/068 drilled by a down-hole drilling motor down-hole drives per se E21B4/00, E21B7/067 takes precedence
• CPC Class Codes: F04D 13/10 adapted for use in mining bore holes
• CPC Class Codes: F04D 15/0066 by changing the speed, e.g. of the driving engine
• CPC Class Codes: H02K 16/025 with rotors and moving stators connected in a cascade cascade arrangement of an asynchronous motor with another dynamo-electric motor or converter H02K17/34
• CPC Class Codes: H02K 17/34 Cascade arrangement of an asynchronous motor with another dynamo-electric motor or converter
• CPC Class Codes: H02K 49/043 with a radial airgap
• CPC Class Codes: H02K 7/1823 structurally associated with turbines or similar engines

Abstract

A combination of a torque-generating apparatus with an alternator/generator. The torque-generating apparatus comprises a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis, and a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4). The first assembly (10, 25) and the second assembly (2) are rotatable relative to each other about the axis. Relative rotation between the first (10, 25) and second (2) assemblies induces a magnetic field which generates rotational torque between the first and second assemblies. Rectification means (31) is provided to convert alternating current electrical output from the alternator/generator (22) to provide D.C. current to the electromagnetic windings (4) of the torque generating apparatus to generate an electromagnetic braking effect.

Claims

1. A combination of a torque-generating apparatus and an alternator/generator positioned axially adjacent to one another on a common shaft (8), the torque-generating apparatus comprising:

a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis, a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4), the first assembly (10, 25) and the second assembly (2) being rotatable relative to each other about the axis;

the alternator/generator incorporating a permanent magnent rotor;

the combination further including rectifications means (31) for converting alternating current electrical output from the alternator/generator (22) to provide direct current to the electromagnetic winding (4) of the torque-generating apparatus, the voltage of which direct current is dependent upon the speed of rotation of the alternator/generator, whereby relative rotation between the first (10, 25) and second (2) assemblies of the torque-generating apparatus induces a magnetic field which generates rotational torque between the first and second assemblies to generate a progessive braking effect dependent on the voltage applied to the electromagnetic winding (4).

2. A combination as claimed in claim 1, wherein the first assembly is a rotor assembly (10, 25) of the torque generating apparatus for producing rotational torque and the second assembly (2) is a stator assembly of the torque generating apparatus.

3. A combination as claimed in claim 1, wherein the second assembly (2) comprises a magnetically soft steel.

4. A combination as claimed in claim 1, wherein the first (10, 25) and second assemblies (2) are separated by a narrow gap.

5. A combination as claimed in claim 1, wherein the first assembly (10, 25) is disposed so as to substantially surround the second assembly (2).

6. A combination as claimed in claim 1, wherein the first assembly is of a form selected from substantially solid (10) or is formed from a plurality of laminations (25).

7. A combination as claimed in claim 1, wherein the second assembly (2) is of a form selected from substantially solid or is formed from a plurality of laminations.

8. A combination as claimed in claim 1, wherein a number of generally longitudinal grooves (20) are provided to the inside surface of the cylindrical member of the first assembly (10).

9. A combination as claimed in claim 8, wherein the grooves (20) are substantially parallel to the longitudinal axis of the first assembly (10).

10. A combination as claimed in claim 8, wherein the grooves (20) are provided so as to form at least a partial helix around the longitudinal axis of the first assembly (10).

11. A combination as claimed in claim 1, wherein the second assembly (2) is provided with a number of pole pieces extending generally radially from the longitudinal axis thereof.

12. A combination as claimed in claim 11, wherein the pole pieces of the second assembly are provided with an electromagnetic winding, adjacent poles being magnetisable in opposite directions.

13. A combination as claimed in claim 11, wherein means is provided to control the degree of the magnetisation.

14. A combination as claimed in claim 11, wherein gaps between the pole pieces are filled with a potting material.

15. A combination as claimed in claim 11, wherein a surface of the second assembly (2) is covered with a layer selected from soft magnetic and non-magnetic material (21).

16. A combination as claimed in claim 1, wherein the first assembly (10, 25) is provided with external rotation means (12) adapted to rotate the first assembly (10, 25).

17. A combination as claimed in claim 16, wherein the external rotation means comprises an impeller (12).

18. A combination as claimed in claim 17, wherein the impeller (12) is adapted to be disposed in use within a moving fluid, the motion of the fluid acting upon the impeller so as to rotate the first assembly.

19. A combination as claimed in claim 1, wherein the alternator/generator (22) is provided with external rotation means (12).

20. A combination as claimed in claim 19, wherein the external rotation means comprises an impeller (12) adapted to rotate the alternator/generator (22).

21. A combination as claimed in claim 20, wherein the impeller (12) is adapted to be disposed in use within a moving fluid, the motion of the fluid acting upon the impeller (12) so as to rotate the alternator/generator (22).

22. A combination as claimed in claim 20, wherein the impeller (12) is an integral part of a magnet carrier of the alternator/generator (22).

23. A combination as claimed in claim 1, wherein the rectified electrical output of the alternator/generator (22) is connected directly to the electromagnetic winding (4) of the torque-generating apparatus to create the electromagnetic braking effect.

24. A combination as claimed in claim 23, wherein the electromagnetic braking effect can be modified by varying the resistance of the electromagnetic winding (4).

25. A combination as claimed in claim 24 wherein the resistance of the electromagnetic winding (4) can be modified by varying the resistance of the electromagnetic winding (4) with at least one external resistance.

26. A combination as claimed in claim 24 wherein the resistance of the electromagnetic winding (4) can be modified by changing the gauge of the winding wire.

27. A combination as claimed in claim 23 wherein in the electromagnetic braking effect can be modified by varying the gap between the first (10, 25) and second (2) assemblies of the torque-generating apparatus.

28. A combination as claimed in claim 1, wherein the rectified electrical output of the alternator/generator (22) is connected indirectly to the electromagnetic winding (4) of the torque-generating apparatus by way of alternator voltage regulation means to create the electromagnetic braking effect.

29. A combination as claimed in claim 1, wherein the progressive braking effect is activated at a predetermined set point.

30. A combination as claimed in claim 29, wherein the predetermined set point is determined by the voltage output of the alternator/generator (22).

31. A combination as claimed in claim 30 wherein the predetermined set point is variable.

32. A method of generating an electromagnetic braking effect in a combination of a torque-generating apparatus and an alternator/generator positioned axially adjacent to one another on a common shaft (8), the torque-generating apparatus comprising:

a first assembly (10, 25) including a generally cylindrical member of magnetically soft material and having a longitudinal axis, a second assembly (2) arranged coaxially within the first assembly and including an electromagnetic winding (4), the first assembly (10, 25) and the second assembly (2) being rotable relative to each other about the axis;

the alternator/generator incorporating a permanent magnet rotor;

the combination further including rectification means (31) for converting alternating current electrical output from the alternator/generator (22) to provide a direct current voltage which is dependent upon the speed of rotation of the alternator/generator, the method including the step of applying the voltage to the electromagnetic winding (4) of the torque-generating apparatus whereby relative rotation between the first (10, 25) and second (2) assemblies of the torque-generating apparatus induces a magnetic field which generates rotational torque between the first and second assemblies to generate a progessive braking effect dependent on the voltage applied to the electromagnetic winding (4).

33. A method according to claim 32 and including the step of connecting the electrical output of the alternator/generator (22) directly to the electromagnetic winding (4) of the torque-generating apparatus to create the electromagnetic braking effect.

34. A method according to claim 33 and including the step of varying the resistance of the electromagnetic winding (4) to modify the electromagnetic braking effect.

35. A method according to claim 34, wherein the resistance of the electromagnetic winding (4) is modified with a least one external resistance.

36. A method according to claim 34, wherein the resistance of the electromagnetic winding (4) is modified by changing the gauge of the winding wire.

37. A method according to claim 33 and including the step of varying the gap between the first (10, 25) and second (2) assemblies of the torque-generating apparatus to modify the electromagnetic braking effect.

38. A method according to claim 32 and including the step of connecting the rectified electrical output of the alternator/generator (22) indirectly to the electromagnetic winding (4) of the torque-generating apparatus by way of alternator voltage regulation means to create the electromagnetic braking effect.

39. A method according to claim 38 and including the step of activating the progressive braking effect at a predetermined set point.

40. A method according to claim 39 wherein the predetermined set point is determined by the voltage output of the alternator/generator (22).

41. A method according to claim 40, wherein the predetermined set point is variable.