Patent US4153921A successfully refreshed from Google Patents.
US4153921A
Expired / Lapsed
US
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Thermally stabilized metal oxide varistors
Assignee: General Electric Co
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Filing: 1978-02-06
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Granted: 1979-05-08
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Expires: 1998-02-06
Abstract
Abstract Zinc oxide varistor protective devices for vapor cooled transformers are integrally located in contact with the transformer coolant liquid to provide cooling capacity to the zinc oxide materials. The zinc oxide varistors are prevented from becoming electrically unstable by keeping the varistor operating temperature at or below the boiling point of the coolant.
Inventors
- 👤 James S. Kresge
- 👤 Richard A. Menelly
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 14:54
CPC Classifications
H; H01; H01C; H01C7/00; H01C7/10; H01C7/12; H02; H02H; H02H7/00; H02H7/04
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
79 words
A method for thermally stabilizing metal oxide varistors of the type used as voltage surge protectors in lightning arresters for vaporizable fluid-cooled electrical apparatus having a heat exchanger comprising the steps of: mounting the metal oxide varistors above the vaporizable coolant for contact with condensed fluid returning from the heat exchanger; connecting one electrode of the metal oxide varistors with an input lead to the electrical apparatus; and connecting the other electrode of the metal oxide varistor to ground.
Claim 2
Independent Claim
79 words
A method for thermally stabilizing metal oxide varistors of the type used as voltage surge protectors in lightning arresters for vaporizable fluid-cooled electrical apparatus having a heat exchanger comprising the steps of: mounting the metal oxide varistors above the vaporizable coolant for contact with condensed fluid returning from the heat exchanger; connecting one electrode of the metal oxide varistors with an input lead to the electrical apparatus; and connecting the other electrode of the metal oxide varistor to ground.
Claim 3
Dependent Claim
46 words
The method of claim 1 including the steps of providing a plurality of the metal oxide varistors in a stack configuration whereby the electrode of one varistor in the stack becomes electrically connected with the following varistor in the stack to form an electrical series arrangement.
Claim 4
Dependent Claim
20 words
The method of claim 1 including the step of at least partially submerging the metal oxide varistor in the fluid.
Claim 5
Dependent Claim
12 words
The method of claim 1 wherein the fluid comprises a condensable coolant.
Claim 6
Dependent Claim
22 words
The method of claim 1 including the step of mounting the metal oxide varistor on at least one electrical feed through bushing.
References Cited (Backward Citations)
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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) | 1982-05-07 | 1982-11-06 | 1983-05-08 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1986-05-07 | 1986-11-06 | 1987-05-08 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1990-05-07 | 1990-11-06 | 1991-05-08 | $7700.00 | Window Closed / Lapsed |