US3984715A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid contact for a DC machine
Assignee: Siemens AG
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Filing: 1974-08-01
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Granted: 1976-10-05
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Expires: 1994-08-01
Abstract
Abstract This invention concerns an improvement in a fluid contact arrangement employed in a DC machine. The invention provides a contact fluid which is interposed between the rotor and the stator of the machine. The fluid is ferromagnetic. Further, the invention provides a magnetic field which is directed perpendicular to the air gap. The effect of the magnetic field on the ferromagnetic contact fluid is such that the fluid is retained within the gap both when the rotor is at a standstill and when it operates at its normal speed.
Inventors
- 👤 Dieter Kullmann
- 👤 Peter Henninger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 03:40
CPC Classifications
H; H02; H02K; H02K31/00; H02K31/04; H01; H01R; H01R39/00; H01R39/02; H01R39/18; H01R39/30; H01R39/64; H01R39/646
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
77 words
In a fluid contact arrangement for use in an electric machine which includes contact fluid interposed in the air gap formed between thr rotor and stator of said machine, the improvement comprising said contact fluid containing ferromagnetic particles, and means for generating a magnetic field in said gap at least approximately radially to the axis of rotation of said rotor, said magnetic field exerting a force on said contact fluid for retaining said fluid in said gap.
Claim 2
Dependent Claim
77 words
In a fluid contact arrangement for use in an electric machine which includes contact fluid interposed in the air gap formed between thr rotor and stator of said machine, the improvement comprising said contact fluid containing ferromagnetic particles, and means for generating a magnetic field in said gap at least approximately radially to the axis of rotation of said rotor, said magnetic field exerting a force on said contact fluid for retaining said fluid in said gap.
Claim 3
Dependent Claim
30 words
The fluid contact arrangement of claim 1, wherein said ferromagnetic contact fluid contains a plurality of ferromagnetic particles mixed in a nonmagnetic liquid metal in at least approximately homogeneous distribution.
Claim 4
Dependent Claim
31 words
The fluid contact arrangement of claim 2, characterized by the feature that the specific gravity of the ferromagnetic particles is at least approximately equal to that of the nonmagnetic liquid metal.
Claim 5
Dependent Claim
42 words
The fluid contact arrangement of claim 1, wherein said means for generating a magnetic field include an electromagnet, whose coils are embedded in the stationary part of said machine and are arranged approximately in ring-shape about the outer periphery of said rotor.
Claim 6
Dependent Claim
36 words
The fluid contact arrangement of claim 4, characterized by the feature that several coils are provided, said coils arranged parallel to each other and one behind the other in the direction of said axis of rotation.
Claim 7
Dependent Claim
23 words
The fluid contact arrangement of claim 5, characterized by the feature that the direction of the current in said coils can be reversed.
Claim 8
Dependent Claim
33 words
the fluid contact arrangement of claim 1 wherein at least one of said rotor or stator includes at least one protrusion extending substantially, radially into said air gap at the axial edges thereof.
Claim 9
Dependent Claim
34 words
The fluid contact arrangement of claim 1 wherein said rotor and stator are configured such that the width of said air gap is smaller at its axial edges than in the central portion thereof.
Claim 10
Dependent Claim
32 words
The fluid contact arrangement of claim 8 wherein at least one of said rotor or stator includes at least one protrusion extending substantially, radially into said air gap at said axial edges.
Claim 11
Dependent Claim
18 words
The fluid contact arrangement of claim 1, characterized by the feature that said magnetic field can be varied.
Claim 12
Dependent Claim
46 words
The fluid contact arrangement of claim 1, characterized by the feature that said magnetic field can be controlled to create a force which points toward the center of said air gap and which acts to restrain said fluid at the axial edges of said air gap.
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) | 1979-10-05 | 1980-04-05 | 1980-10-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-10-05 | 1984-04-05 | 1984-10-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-10-05 | 1988-04-05 | 1988-10-05 | $7700.00 | Window Closed / Lapsed |