Patent US2969809A successfully refreshed from Google Patents.
US3836799A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Linear induction motor with electromagnetic levitation
Assignee: Individual
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Filing: 1973-05-14
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Granted: 1974-09-17
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Expires: 1993-05-14
Abstract
Abstract In a combined electromagnetic levitation arrangement and linear induction motor, the secondary consists of a sheet of electrically conductive non-magnetic material. The primary consists of a core of magnetic material providing paths for working flux in planes perpendicular to the desired direction of relative movement between the primary and the secondary, and polyphase windings on the core.
Inventors
- 👤 J Eastham
- 👤 E Laithwaite
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 00:41
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/025
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
211 words
An electrical machine having a secondary comprising electrically conductive material and a primary comprising a core of magnetic material having at least two rows of pole faces disposed side by side confronting one side of said secondary with a single horizontal airgap therebetween, said core being arranged to provide paths for working flux between said pole faces in planes substantially perpendicular to said rows of pole faces and having polyphase windings thereon, the secondary being arranged to provide longitudinal paths for electric current on each side of each row of pole faces and transverse paths for electric current interconnecting said longitudinal paths, the primary being arranged, when energized from a polyphase alternating current supply, to create a magnetic field operative to produce a force between said primary and said secondary having first components tending to maintain said primary and secondary spaced apart from one another, second components tending to maintain said primary and said secondary in alignment with one another in a direction perpendicular to said rows of pole faces whereby one of said primary and said secondary is supported in a stable position above the other and third components tending to cause relative displacement between said primary and said secondary in a direction parallel to said rows of pole faces.
Claim 2
Dependent Claim
211 words
An electrical machine having a secondary comprising electrically conductive material and a primary comprising a core of magnetic material having at least two rows of pole faces disposed side by side confronting one side of said secondary with a single horizontal airgap therebetween, said core being arranged to provide paths for working flux between said pole faces in planes substantially perpendicular to said rows of pole faces and having polyphase windings thereon, the secondary being arranged to provide longitudinal paths for electric current on each side of each row of pole faces and transverse paths for electric current interconnecting said longitudinal paths, the primary being arranged, when energized from a polyphase alternating current supply, to create a magnetic field operative to produce a force between said primary and said secondary having first components tending to maintain said primary and secondary spaced apart from one another, second components tending to maintain said primary and said secondary in alignment with one another in a direction perpendicular to said rows of pole faces whereby one of said primary and said secondary is supported in a stable position above the other and third components tending to cause relative displacement between said primary and said secondary in a direction parallel to said rows of pole faces.
Claim 3
Dependent Claim
20 words
An electrical machine as claimed in claim 1, in which the secondary comprises a sheet of electrically conductive non-magnetic material.
Claim 4
Dependent Claim
23 words
An electrical machine as claimed in claim 2, in which the core of the primary comprises a row of members of U-shaped cross-section.
Claim 5
Dependent Claim
31 words
An electrical machine as claimed in claim 3, in which the polyphase windings comprise a set of coils each of which encircles at least two adjacent members of the primary core.
Claim 6
Dependent Claim
41 words
An electrical machine as claimed in claim 2, in which the primary is formed in two sections disposed side by side, each section comprising at least two rows of pole faces confronting the secondary and a respective set of polyphase windings.
Claim 7
Dependent Claim
23 words
An electrical machine as claimed in claim 5, in which each sectiOn of the primary comprises a row of members of U-shaped cross-section.
Claim 8
Dependent Claim
31 words
An electrical machine as claimed in claim 6, in which the polyphase windings comprise a set of coils each of which encircles at least two adjacent members of the primary core.
Claim 9
Dependent Claim
23 words
An electrical machine as claimed in claim 4, in which each section of the primary comprises a row of members of E-shaped cross-section.
Claim 10
Dependent Claim
31 words
An electrical machine as claimed in claim 8, in which the polyphase windings comprise a set of coils each of which encircles at least two adjacent members of the primary core.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-16 | 1978-03-18 | 1978-09-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-16 | 1982-03-18 | 1982-09-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-16 | 1986-03-18 | 1986-09-17 | $7700.00 | Window Closed / Lapsed |