US4013906A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electromagnetic levitation
Assignee: National Research Development Corp UK
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Filing: 1975-05-12
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Granted: 1977-03-22
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Expires: 1995-05-12
Abstract
Abstract In a combined linear motor and levitation arrangement, the primary comprises two longitudinally extending rows of transverse U-cores disposed side by side. The secondary comprises electrically conductive non-magnetic material backed by magnetic material. The magnetic material of the secondary is formed in two parts each of which is associated with a respective row of U-cores of the primary.
Inventors
- 👤 John Frederick Eastham
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-24 23:36
CPC Classifications
H; H02; H02K; H02K41/00; H02K41/02; H02K41/025; H02N; H02N15/00
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
201 words
An electrical machine having a primary comprising a core of magnetic material having at least two pairs of rows of pole faces disposed in a common plane and arranged to provide paths for working flux between the pole faces of each row in planes substantially perpendicular to said rows, and a secondary confronting said pole faces and comprising electrically conductive material arranged to provide longitudinal paths for electric current on each side of each row of pole faces and transverse paths interconnecting said longitudinal paths and at least one core member of magnetic material extending longitudinally of the electrically conductive material on the opposite side thereof to the primary and having its lateral edges so disposed relative to the primary that the magnetic field produced when the primary is energised from a polyphase alternating current supply is operative to produce a force between said primary and said secondary having first components tending to maintain said primary and said secondary spaced apart from one another, second components tending to maintain said primary and said secondary in alignment with one another in a lateral direction and third components tending to cause relative displacement between said primary and said secondary in a longitudinal direction.
Claim 2
Dependent Claim
201 words
An electrical machine having a primary comprising a core of magnetic material having at least two pairs of rows of pole faces disposed in a common plane and arranged to provide paths for working flux between the pole faces of each row in planes substantially perpendicular to said rows, and a secondary confronting said pole faces and comprising electrically conductive material arranged to provide longitudinal paths for electric current on each side of each row of pole faces and transverse paths interconnecting said longitudinal paths and at least one core member of magnetic material extending longitudinally of the electrically conductive material on the opposite side thereof to the primary and having its lateral edges so disposed relative to the primary that the magnetic field produced when the primary is energised from a polyphase alternating current supply is operative to produce a force between said primary and said secondary having first components tending to maintain said primary and said secondary spaced apart from one another, second components tending to maintain said primary and said secondary in alignment with one another in a lateral direction and third components tending to cause relative displacement between said primary and said secondary in a longitudinal direction.
Claim 3
Dependent Claim
20 words
An electrical machine as claimed in claim 1, in which the primary comprises two longitudinally extending rows of U-shaped cores.
Claim 4
Dependent Claim
45 words
An electrical machine as claimed in claim 2, in which the secondary comprises a continuous sheet of electrically conductive material confronting both pairs of rows of pole faces and a respective core member of magnetic material for each row of pairs of primary pole faces.
Claim 5
Dependent Claim
30 words
An electrical machine as claimed in claim 3, in which the magnetic core members of the secondary are inwardly displaced with respect to the pairs of rows of pole faces.
Claim 6
Dependent Claim
36 words
An electrical machine as claimed in claim 2, in which the secondary comprises a respective sheet of electrically conductive material and a respective core member of magnetic material for each row of pairs of pole faces.
Claim 7
Dependent Claim
32 words
An electrical machine as claimed in claim 3, in which the width of each of the secondary core members is equal to the overall width of the corresponding pair of primary faces.
Claim 8
Dependent Claim
32 words
An electrical machine as claimed in claim 5, in which the width of each of the secondary core members is equal to the overall width of the corresponding pair of primary faces.
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) | 1980-03-21 | 1980-09-20 | 1981-03-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1984-03-21 | 1984-09-20 | 1985-03-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1988-03-21 | 1988-09-20 | 1989-03-22 | $7700.00 | Window Closed / Lapsed |