Electromechanical actuator

• US 20110068884A1
• Filed: 08/17/2010
• Published: 03/24/2011
• Est. Priority Date: 05/20/2004
• Status: Active Grant

• Current Assignee: PowerPath Technologies, Inc
• Original Assignee: PowerPath Technologies LLC
• Inventors: Brooks, Elliot
• Granted Patent: US 8,134,438 B2
• Time in Patent Office: Days
• US Class Current: 335/100
• CPC Class Codes: H01F 2007/086 Structural details of the armature
• CPC Class Codes: H01F 7/1607 Armatures entering the winding
• CPC Class Codes: H01H 1/38 Plug-and-socket contacts
• CPC Class Codes: H01H 2300/018 Application transfer; between utility and emergency power supply circuits in H02J9/04
• CPC Class Codes: H01H 3/222 using electrodynamic repulsion
• CPC Class Codes: H01H 33/161 Variable impedances
• CPC Class Codes: H02K 33/02 with armatures moved one way by energisation of a single coil system and returned by mechanical force, e.g. by springs
• CPC Class Codes: H02K 41/0356 moving along a straight path

Abstract

The present invention is directed to an inductively driven electromagnetic linear actuator arrangement employing eddy currents induced in an armature by a drive coil to drive the armature. Eddy current focusing fields (Lorentz force) are employed to direct the induced eddy currents to maximize armature speed. The armature includes a shorted driven coil in a DC magnetic field that focuses eddy currents induced by the drive coil in the driven coil. The DC magnetic field can be supplied by one or more permanent magnets. When current is applied to the drive coil, a force is felt by the driven coil in a direction perpendicular to the magnetic field, causing armature movement. Such an actuator is well suited for electrical switching applications including transfer switching applications, circuit breaker applications, and ground fault interrupter applications.

Claims

1. An electromagnetic actuator comprising:

a drive coil that produces a magnetic field when electrical current is applied;

a driven element movable relative to the drive coil;

a power supply electrically connected to the drive coil; and

wherein application of electrical current by the power supply to the drive coil inductively couples the driven element with the drive coil inducing eddy current flow in the driven element causing the driven element to move relative to the drive coil.

2. The electromagnetic actuator of claim 1 wherein the driven element is comprised of a non-ferrous electrically conductive material.

3. The electromagnetic actuator of claim 2 wherein the driven element is comprised of a non-magnetizable material.

4. The electromagnetic actuator of claim 3 wherein the driven element is of shorted-turn unpowered construction.

5. The electromagnetic actuator of claim 4 wherein the driven element is generally tubular and is generally coaxial with the drive coil.

6. The electromagnetic actuator of claim 1 further comprising a Lorentz force eddy current flow focusing arrangement that interacts with eddy currents induced in the driven element directing eddy current flow.

7. The electromagnetic actuator of claim 6 wherein the Lorentz force eddy current flow focusing arrangement comprises a source of a steady state magnetic field.

8. The electromagnetic actuator of claim 7 wherein the steady state magnetic field source comprises a permanent magnetic disposed adjacent the driven element.

9. The electromagnetic actuator of claim 1 further comprising a pair of spaced apart steady state magnetic field sources with one of the magnetic field sources disposed on one side of the driven element and the other one of the magnetic field sources disposed on an opposite side of the driven element.

10. The electromagnetic actuator of claim 9 wherein the one of the magnetic field sources has a magnetic pole disposed adjacent the driven element having a magnetic polarity opposite the polarity of a magnetic pole disposed of the other one of the magnetic field sources.

11. The electromagnetic actuator of claim 10 wherein each one of the pair of steady state magnetic field sources comprises a permanent magnet.

12. The electromagnetic actuator of claim 1 wherein the driven element is of non-ferrous electrically conductive construction, is generally coaxial with the drive coil, is movable in one direction relative to the drive coil when electrical current having one polarity is applied by the power supply to the drive coil, and is movable in an opposite direction relative to the drive coil when electrical current having an opposite polarity is applied by the power supply to the drive coil.

13. The electromagnetic actuator of claim 12 wherein the driven element is tubular and the drive coil is comprised of at least a plurality of electrically conductive turns or windings.

14. The electromagnetic actuator of claim 1 wherein the driven element is of tubular, non-magnetizable electrically conductive construction, is generally coaxial with the drive coil, is movable between a plurality of positions, is movable in one direction relative to the drive coil when electrical current having one polarity is applied by the power supply to the drive coil, and is movable in an opposite direction relative to the drive coil when electrical current having an opposite polarity is applied by the power supply to the drive coil.

15. The electromagnetic actuator of claim 1 further comprising a stator carrying the drive coil comprising a magnetic flux conducting center post, a magnetic flux conducting sidewall, and a pair of magnetic flux conducting endwalls providing an actuator of closed magnetic circuit construction, wherein the driven element moves generally parallel to the center post, and wherein the drive coil is fixed relative to the stator.

16. The electromagnetic actuator of claim 15 wherein the stator further comprises at least one source of a steady state magnetic field directed toward the driven element.

17. The electromagnetic actuator of claim 15 wherein the driven element is tubular and generally coaxial with the center post.

18. The electromagnetic actuator of claim 17 wherein the driven element is comprised of a non-magnetizable electrically conductive material.

19. The electromagnetic actuator of claim 17 wherein the driven element is comprised of a non-ferrous electrically conductive material.

20. The electromagnetic actuator of claim 17 wherein the drive coil is carried by the center post and comprised of at least a plurality of electrically conductive turns or windings.

21. An electromagnetic actuator comprising:

a drive coil that produces a first magnetic field when electrical current is applied;

a non-ferrous electrically conductive driven element of shorted turn construction that is movable relative to the drive coil;

a source of a second magnetic field disposed adjacent the driven element;

a power supply electrically connected to the drive coil;

wherein application of electrical current by the power supply to the drive coil inductively couples the driven element with the drive coil inducing eddy current flow in the driven element giving rise to a third magnetic field that interacts with the first magnetic field causing the driven element to move relative to the drive coil; and

wherein the second magnetic field directs eddy current flow along the driven element.

22. An electromagnetic actuator comprising:

a drive coil that produces a first magnetic field when electrical current is applied;

a non-magnetizable electrically conductive driven element of shorted turn construction that is movable relative to the drive coil;

a Lorentz force eddy current flow focusing arrangement disposed adjacent the driven element that directs eddy current flow in the driven element;

a power supply electrically connected to the drive coil; and

wherein application of electrical current by the power supply to the drive coil inductively couples the driven element with the drive coil inducing eddy current flow in the driven element giving rise to a third magnetic field that interacts with the first magnetic field causing the driven element to move relative to the drive coil.