US3704391A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Cryogenic current limiting switch
Assignee: ABB Inc USA
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Filing: 1970-11-10
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Granted: 1972-11-28
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Expires: 1990-11-10
Abstract
Abstract A superconductive element to be used for current limiting action is arranged in the interior of a tubular conductor and is in a substantially field-free region during normal current conduction. The vacuum used as thermal insulation for the superconductor element is further used as a switching medium for the contacts of switching devices associated with the superconductor. A nonlinear resistor material such as pure tungsten is connected in parallel with the superconductor so that current commutates into the non-linear resistor when the superconductor switches to its normal conduction characteristics.
Inventors
- 👤 Lorne D Mcconnell
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 07:32
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/02; H02H9/023; H10; H10N; H10N60/00; H10N60/30; H10N60/35; H10N60/355; Y; Y02; Y02E; Y02E40/00; Y02E40/60; Y10; Y10S; Y10S505/00; Y10S505/825; Y10S505/85
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
230 words
A current limiting device comprising, in combination: a first elongated conductor of material having superconducting properties at temperatures below a given temperature; a cryogenic vessel surrounding said first elongated conductor for cooling said first elongated conductor to a temperature below said given temperature; a second elongated electrical conductor defining a hollow tubular shape surrounding said first elongated conductor, whereby said first elongated conductor is in a region substantially free of any magnetic field due to current conduction by said second elongated conductor; said second elongated conductor connectable at its opposite ends to a first and second terminal, defining the terminals of said current limiting device; and first and second means connected to first and second ends of said first elongated conductor for connecting said first elongated conductor to said first and second terminals, respectively; said first means comprising a switch means operable between an open and closed position, whereby, when said switch means is open, current conduction between said first and second terminals is through said second elongated conductor, and said first elongated conductor is maintained in a superconducting state independently of the magnetic field created by current flow in said second elongated conductor, and whereby a path for current flow, which can generate a magnetic field for switching said first elongated conductor to a resistive state, is defined through said first elongated conductor when said switch means is closed.
Claim 2
Dependent Claim
230 words
A current limiting device comprising, in combination: a first elongated conductor of material having superconducting properties at temperatures below a given temperature; a cryogenic vessel surrounding said first elongated conductor for cooling said first elongated conductor to a temperature below said given temperature; a second elongated electrical conductor defining a hollow tubular shape surrounding said first elongated conductor, whereby said first elongated conductor is in a region substantially free of any magnetic field due to current conduction by said second elongated conductor; said second elongated conductor connectable at its opposite ends to a first and second terminal, defining the terminals of said current limiting device; and first and second means connected to first and second ends of said first elongated conductor for connecting said first elongated conductor to said first and second terminals, respectively; said first means comprising a switch means operable between an open and closed position, whereby, when said switch means is open, current conduction between said first and second terminals is through said second elongated conductor, and said first elongated conductor is maintained in a superconducting state independently of the magnetic field created by current flow in said second elongated conductor, and whereby a path for current flow, which can generate a magnetic field for switching said first elongated conductor to a resistive state, is defined through said first elongated conductor when said switch means is closed.
Claim 3
Dependent Claim
36 words
The current limiting device of claim 1 wherein said switch means is operable to switch all current flow between said first and second terminals from said second conductor to said first conductor responsive to operation thereof.
Claim 4
Dependent Claim
36 words
The current limiting device of claim 2 wherein said switch means is further operable to open the circuit between said first and second terminals after switching current flow from said second conductor to said first conductor.
Claim 5
Dependent Claim
33 words
The current limiting device of claim 2 wherein said second means connected to said second end of said first elongated conductor comprises second switch means operable between an open and a closed position.
Claim 6
Dependent Claim
34 words
The current limiting device of claim 1 which includes an external evacuated housing surrounding said cryogenic vessel and said second elongated conductor; said switch means being disposed within the vacuum of said evacuated housing.
Claim 7
Dependent Claim
34 words
The current limiting device of claim 2 which includes an external evacuated housing surrounding said cryogenic vessel and said second elongated conductor; said switch means being disposed within the vacuum of said evacuated housing.
Claim 8
Dependent Claim
34 words
The current limiting device of claim 3 which includes an external evacuated housing surrounding said cryogenic vessel and said second elongated conductor; said switch means being disposed within the vacuum of said evacuated housing.
Claim 9
Dependent Claim
112 words
The current limiting device comprising, in combination: an elongated conductor of material having superconducting properties at temperatures below a given temperature; cryogenic cooling means asSociated with said elongated conductor for cooling said elongated conductor to a temperature below said given temperature; switch means connected to one end of said elongated conductor and in series with said elongated conductor; first and second terminals for connecting said switch means sand said elongated conductor in series with a circuit; and a common evacuated housing surrounding said switch means and said elongated conductor, to serve as thermal insulation for said elongated conductor and as a vacuum medium for operating said switch means as a vacuum switch.
Claim 10
Dependent Claim
112 words
The current limiting device comprising, in combination: an elongated conductor of material having superconducting properties at temperatures below a given temperature; cryogenic cooling means asSociated with said elongated conductor for cooling said elongated conductor to a temperature below said given temperature; switch means connected to one end of said elongated conductor and in series with said elongated conductor; first and second terminals for connecting said switch means sand said elongated conductor in series with a circuit; and a common evacuated housing surrounding said switch means and said elongated conductor, to serve as thermal insulation for said elongated conductor and as a vacuum medium for operating said switch means as a vacuum switch.
Claim 11
Dependent Claim
31 words
The device of claim 8 which includes a second switch means in series with said elongated conductor and connnected to the end of said elongated conductor opposite to said one end.
Claim 12
Dependent Claim
107 words
A current limiting device comprising, in combination: an elongated conductor of material having a positive temperature coefficient of resistance which changes value by at least several orders of magnitude when heated through a given temperature range; switch means connected to one end of said elongated conductor and in series with said elongated conductor; first and second terminals for connecting said switch means and said elongated conductor in series with a circuit; and a common evacuated housing surrounding said switch means and said elongated conductor, to serve as thermal insulation for said elongated conductor and as a vacuum medium for operating said switch means as a vacuum switch.
Claim 13
Dependent Claim
107 words
A current limiting device comprising, in combination: an elongated conductor of material having a positive temperature coefficient of resistance which changes value by at least several orders of magnitude when heated through a given temperature range; switch means connected to one end of said elongated conductor and in series with said elongated conductor; first and second terminals for connecting said switch means and said elongated conductor in series with a circuit; and a common evacuated housing surrounding said switch means and said elongated conductor, to serve as thermal insulation for said elongated conductor and as a vacuum medium for operating said switch means as a vacuum switch.
Claim 14
Dependent Claim
167 words
A current limiting device comprising, in combination: a first elongated conductor of material having superconductor properties at temperatures below a given temperature; a second elongated resistive conductor connected in parallel with said first elongated conductor; a cooling means for said first and second elongated conductors for cooling at said first and second elongated conductors to a first temperature below said given temperature; said first elongated conductor being switched out of its superconducting state to a resistive state responsive to the magnetic field of the current flow therethrough which exceeds a given value; said second conductor having a resistance which is lower than the resistance of said first conductor at a temperature about equal to said first temperature and after said first conductor is switched from its said superconducting state; the resistance of said second conductor being lower than the resistance of said first conductor throughout a temperature range from said first temperature to a second temperature to which said second conductor is heated by the current therethrough.
Claim 15
Dependent Claim
167 words
A current limiting device comprising, in combination: a first elongated conductor of material having superconductor properties at temperatures below a given temperature; a second elongated resistive conductor connected in parallel with said first elongated conductor; a cooling means for said first and second elongated conductors for cooling at said first and second elongated conductors to a first temperature below said given temperature; said first elongated conductor being switched out of its superconducting state to a resistive state responsive to the magnetic field of the current flow therethrough which exceeds a given value; said second conductor having a resistance which is lower than the resistance of said first conductor at a temperature about equal to said first temperature and after said first conductor is switched from its said superconducting state; the resistance of said second conductor being lower than the resistance of said first conductor throughout a temperature range from said first temperature to a second temperature to which said second conductor is heated by the current therethrough.
Claim 16
Dependent Claim
29 words
The device of claim 11 wherein said first conductor has the form of a hollow conductive tube, and wherein said second conductor is disposed within said hollow conductive tube.
Claim 17
Dependent Claim
36 words
The current limiting device of claim 12 wherein said first and second conductors are immersed in a cryogenic cooling liquid; and an evacuated housing enclosing said cryogenic cooling liquid and said first and second elongated conductors.
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) | 1975-11-28 | 1976-05-29 | 1976-11-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-11-28 | 1980-05-29 | 1980-11-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-11-28 | 1984-05-29 | 1984-11-28 | $7700.00 | Window Closed / Lapsed |