Patent US3743996A successfully refreshed from Google Patents.
US3743996A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Protective pads for electrical devices
Assignee: General Electric Co
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Filing: 1971-10-21
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Granted: 1973-07-03
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Expires: 1991-10-21
Abstract
Abstract A plurality of elongated lead-in electrodes are hermetically sealed in a wafer of metal oxide varistor material and extend therethrough. The portions of the wafer in contact with said electrodes are spaced to provide a current flow between the electrodes which is low when normal operating voltage appears across the electrodes and when voltages in excess of normal voltage appear progressively thereacross a rapidly decreasing impedance is presented by the wafer in accordance with the alpha of the body of material, thereby limiting the voltage appearing between the electrodes.
Inventors
- 👤 J Harnden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-05 11:44
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
30 words
The combination of claim 1 in which said material has an alpha in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter.
Claim 2
Dependent Claim
76 words
The combination of claim 1 in which the portions of said body in contact with said electrodes are spaced to provide a current flow between said electrodes which is low when normal operating voltage appears across said electrodes and when voltages in excess of normal voltage progressively appear thereacross a rapidly decreasing impedance is presented by said body in accordance with the alpha of the body of material thereby limiting the voltage appearing between said electrodes.
Claim 3
Dependent Claim
29 words
The combination of claim 1 in which said other electrode is an elongated electrode and extends through said body from one opposed surface to the other opposed surface thereof.
Claim 4
Dependent Claim
18 words
The combination of claim 1 in which said other electrode is a conductive member which surrounds said body.
Claim 5
Dependent Claim
17 words
The combination of claim 1 in which one of said surfaces is provided with an insulating coating.
Claim 6
Dependent Claim
145 words
An electrical feed-through assembly comprising a wafer of metallic oxide varistor material having a pair of opposed surfaces, a plurality of elongated electrodes, each extending through said wafer from one opposed surface to the other opposed surface thereof and in conductive contact therewith, said material having an essentially constant alpha in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter, decreasing the portions of said wafer in contact with said electrodes being spaced to provide a current flow between a pair of said electrodes which is low when normal operating voltage appears across said pair of electrodes and when voltages in excess of normal voltage appear thereacross a rapidly decreasing impedance is presented by said wafer in accordance with the alpha of The material of said wafer thereby limiting the voltage appearing between said pair of electrodes.
Claim 7
Dependent Claim
63 words
The combination of claim 7 in which one of said surfaces is provided with a pair of spaced conductive layers, each in conductive contact with a respective one of a pair of said electrodes, the distance between said layers along said one surface being set to obtain a desired normal operating point on the voltage versus current graph of one pair of electrodes.
Claim 8
Dependent Claim
68 words
The combination of claim 8 in which the other of said surfaces is provided with another pair of spaced conductive layers, each in conductive contact with a respective one of another pair of said electrodes, the distance between said other pair of layers along said other surface being set to obtain a desired normal operating point on the voltage versus current graph of said other pair of electrodes.
References Cited (Backward Citations)
US2075733A
Cited
US3024435A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-07-02 | 1977-01-01 | 1977-07-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-02 | 1981-01-01 | 1981-07-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-02 | 1985-01-01 | 1985-07-03 | $7700.00 | Window Closed / Lapsed |