US4365282A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overvoltage protector using varistor initiated arc
Assignee: United States Department of Energy
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Filing: 1980-02-14
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Granted: 1982-12-21
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Expires: 2000-02-14
Abstract
Abstract Coaxial conductors are protected against electrical overvoltage by at least one element of non-electroded varistor material that adjoins each other varistor element and conductor with which it contacts. With this construction, overvoltage current initiated through the varistor material arcs at the point contacts between varistor elements and, as the current increases, the arcs increase until they become a continuous arc between conductors, bypassing the varistor material.
Inventors
- 👤 John P. Brainard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 23:27
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/12; H01R; H01R13/00; H01R13/66; H01R13/665; H01R13/6666; H01T; H01T4/00; H01T4/08
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
126 words
An electrical overvoltage protection device comprising first electrically conductive means for carrying an electric signal subject to overvoltage; second electrically conductive means spaced from said first means a minimum distance X for dissipating the overvoltage; insulator means forming with said first and second conductive means an enclosure; and means within the enclosure for conducting the overvoltage consisting of at least one element of non-electroded varistor material in essentially only point or line contact with and providing a first high impedance current path between said conductive means, said material including no element having a minimum cross-sectional dimension less than 0.2X, and an arc-sustaining gas providing a secondary lower impedance current path between said conductive means when initiated by arcs that form at said point or line contacts.
Claim 2
Dependent Claim
126 words
An electrical overvoltage protection device comprising first electrically conductive means for carrying an electric signal subject to overvoltage; second electrically conductive means spaced from said first means a minimum distance X for dissipating the overvoltage; insulator means forming with said first and second conductive means an enclosure; and means within the enclosure for conducting the overvoltage consisting of at least one element of non-electroded varistor material in essentially only point or line contact with and providing a first high impedance current path between said conductive means, said material including no element having a minimum cross-sectional dimension less than 0.2X, and an arc-sustaining gas providing a secondary lower impedance current path between said conductive means when initiated by arcs that form at said point or line contacts.
Claim 3
Dependent Claim
16 words
The electrical overvoltage protection device of claim 1 wherein said gas is air at atmospheric pressure.
Claim 4
Dependent Claim
68 words
The electrical overvoltage protection device of claim 1 wherein said second conductive means forms the inner surface of a metal annulus; said first conductive means is an elongated metal pin disposed generally parallel to the axis of and extending through said annulus; and said insulating means comprise a pair of spaced generally parallel surfaces of insulating material extending from said annulus to said pin, thereby forming the enclosure.
Claim 5
Dependent Claim
101 words
The electrical overvoltage protection device of claim 1 wherein said second conductive means comprises a metal plate having at least one hole extending from an upper surface to a lower surface; said first conductive means comprises at least one elongated metal pin, disposed generally parallel to the axis of and extending through a respective hole; and said insulator means comprises a pair of parallel layers of insulator material, one of said layers covering the upper surface of said plate and the other of said layers covering the lower surface of said plate, each said pin extending through each of said layers.
Claim 6
Dependent Claim
19 words
The electrical overvoltage protection device of claim 4 wherein each of said layers contacts a surface of said plate.
Claim 7
Dependent Claim
44 words
The electrical overvoltage protection device of claim 1 wherein said varistor material consists of a plurality of elements having a maximum cross-sectional dimension less than about 0.8X, each element making essentially a point or line contact with each adjoining other element or conductive means.
Claim 8
Dependent Claim
30 words
The electrical overvoltage protection device of claim 6 wherein each of said elements generally has the form of an ellipsoid having a longest side with a dimension of about 0.5X.
Claim 9
Dependent Claim
58 words
The electrical overvoltage protection device of claim 3 wherein said varistor material consists of a tubular sleeve surrounding said pin, said sleeve having an inner diameter greater than the diameter of said pin, a thickness equal to X and an outer diameter less than the diameter of said annulus, whereby said pin is not centered in said annulus.
Claim 10
Dependent Claim
26 words
The electrical overvoltage protection device of claim 4 wherein said varistor material consists of a plurality of elements having a minimum cross-sectional dimension greater than 1.1X.
Claim 11
Dependent Claim
66 words
The electrical overvoltage protection device of claim 4 wherein at least one said metal pin has a radial metal shoulder extending towards said metal plate at the level of the upper surface, and said varistor material comprises a torus having a concave cross section disposed over said pin with an inner edge contacting said shoulder and an outer edge contacting the upper surface of said plate.
Claim 12
Dependent Claim
30 words
The electrical overvoltage protection device of claim 3 wherein each of said surfaces of insulating material has a diameter equal to the diameter of the inner surface of said annulus.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1985-12-20 | 1986-06-21 | 1986-12-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1989-12-20 | 1990-06-21 | 1990-12-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1993-12-20 | 1994-06-21 | 1994-12-21 | $7700.00 | Window Closed / Lapsed |