Electrical generator with ferrofluid bearings

• US 6,809,427 B2
• Filed: 02/02/2004
• Issued: 10/26/2004
• Est. Priority Date: 02/19/2002
• Status: Expired due to Fees

• Current Assignee: Teledyne Scientific & Imaging, LLC (Teledyne Technologies Incorporated)
• Original Assignee: Rockwell Scientific Licensing LLC
• Inventors: Xin, Hao, Cheung, Jeffrey T.
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US10/770,957
• Publication Number:
  US 20040155467A1
• Time in Patent Office: 267 Days
• Field of Search: 290/1.R, 322/3, 310/66
• US Class Current: 290/1.00R
• CPC Class Codes: F21L 13/06 with mechanical drive, e.g. spring
• CPC Class Codes: H02K 35/02 with moving magnets and stationary coil systems
• CPC Class Codes: H02K 7/088 radially supporting the rotor directly

Abstract

An electrical generator includes a magnet constrained to move relative to a conductor by a support structure, with a ferrofluid bearing providing an ultra low friction interface between the magnet and support structure. The assembly has a critical angle of displacement from a horizontal static position of less than 1 degree, and preferably less than 10 minutes. An electrical signal is generated in the conductor by the moving magnetic field.

Claims

1. An electrical system, comprising:

a magnet constrained to move relative to a support structure,

a ferrofluid disposed between said magnet and support structure to provide a low friction interface,

a conductive coil disposed with respect to said magnet so that relative movement between said magnet and said coil generates an electrical signal in said coil,

a pair of end magnets on opposite sides of, and opposing polarity to, said magnet to limit said magnet'"'"'s movement, and

an operating system coupled to be provided with electrical energy by said electrical signal.

2. The electrical system of claim 1, wherein said coil is disposed along a portion of said support structure which is traversed by said magnet'"'"'s movement.

3. The electrical system of claim 1, wherein said magnet is arranged with respect to said support structure to provide an air flow path between opposite sides of the magnet when the magnet moves.

4. The electrical system of claim 3, wherein said magnet is inside said support structure and occupies less than the full interior cross-sectional area of said support structure, providing said air flow path around the periphery of said magnet.

5. The electrical system of claim 1, wherein said support structure is a generally tubular enclosure.

6. The electrical system of claim 1, wherein said support structure is arranged for said magnet to move relative to the support structure in response to a generally horizontal movement of the support structure.

7. The electrical system of claim 1, wherein said support structure is arranged to be carried by a person and for said magnet to move in a reciprocating motion relative to the support structure in response to motion of the person.

8. The electrical system of claim 7, wherein said support structure is curved.

9. The electrical system of claim 1, wherein said support structure is housed in a buoyant outer enclosure for relative movement between said magnet and coil that generates an electrical signal in said coil when said outer enclosure is floating on a liquid and subjected to wave action.

10. The electrical system of claim 1, further comprising a suspension system for suspending said support structure so that the support structure moves and causes said magnet to generate an electrical signal in said coil in response to wind striking the support structure.

11. The electrical system of claim 1, wherein said ferrofluid has a viscosity less than 5 centipoise.

12. The electrical system of claim 1, wherein said ferrofluid comprises a light mineral oil medium mixed with isoparaffinic acid.

13. The electrical system of claim 1, further comprising circuitry for coupling energy from said coil out of said generator to said operating system.

14. The electrical system of claim 1, wherein said support structure provides said magnet with a critical angle of displacement from a horizontal static position of less than 1 degree.

15. The electrical system of claim 14, wherein said critical angle of displacement is less than 10 minutes.

16. The electrical system of claim 1, wherein said support structure includes a raceway for said magnet.

17. The electrical system of claim 1, said operating system comprising a battery charger having a battery contact, said coil connected to couple electrical energy to said battery contact in response to relative movement between said magnet and coil.

18. The electrical system of claim 1, said operating system comprising an environmental sensor arranged to produce an output signal indicative of an environmental condition, said coil connected to couple electrical energy to said environmental sensor in response to relative movement between said magnet and coil.

19. The electrical system of claim 18, said sensor including a transmitter energized by said energizing signal for transmitting a signal indicative of said environmental condition.

20. The electrical system of claim 1, said operating system including a battery, said coil connected to couple electrical energy to said battery in response to relative movement between said magnet and coil.

21. The electrical system of claim 1, said coil connected to supply an energizing signal to said operating system in real time.

22. The electrical system of claim 1, further comprising a rectifying circuit, said coil connected to couple electrical energy to said operating system through said rectifying circuit.

23. The electrical system of claim 1, said operating system comprising an emergency signal transmitter, said coil connected to couple electrical energy to said transmitter in response to relative movement between said magnet and coil.

24. The electrical system of claim 1, said operating system comprising a cellular telephone, said coil connected to couple electrical energy to said cellular telephone in response to relative movement between said magnet and coil.