Electrical generator with ferrofluid bearings

• US 6,812,583 B2
• Filed: 02/19/2002
• Issued: 11/02/2004
• 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 (Teledyne Technologies Incorporated)
• Inventors: Xin, Hao, Cheung, Jeffrey T.
• Primary Examiner(s): Ponomarenko, Nicholas
• Application Number:
  US10/078,724
• Publication Number:
  US 20030155771A1
• Time in Patent Office: 987 Days
• Field of Search: 290/1.R, 290/1.A, 290/45, 322/1, 322/3, 310/15, 310/17
• 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 generator, comprising:

a magnet constrained to move relative to an enclosure,

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

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

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

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

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

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

5. The electrical generator of claim 1, wherein said enclosure is generally tubular.

6. The electrical generator 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 generator 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 generator of claim 7, wherein said enclosure is curved.

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

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

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

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