US3855508A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Electrical capacitors having substituted ester impregnants
Assignee: Sprague Electric Co
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Filing: 1973-06-13
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Granted: 1974-12-17
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Expires: 1993-06-13
Abstract
Abstract Esters having substituents around the ester grouping to effectively prevent hydrolytic attack are used as impregnants in AC and energy storage capacitors. Appropriate substitution on an adjacent member of an aromatic ring or on either the acid or the alcohol moieties of the ester insures the hydrolytic stability of the esters.
Inventors
- 👤 S Ross
- 👤 M Finkelstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 12:54
CPC Classifications
H; H01; H01G; H01G4/00; H01G4/002; H01G4/018; H01G4/20; H01G4/22; H01G4/221; H01G4/06; H01G4/14; H01G4/18; H01G4/32
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
88 words
AN ELECTRICAL CAPACITOR COMPRISING A CAPACITANCE SECTION HAVING AT LEAST A PAIR OF ELECTRODES WITH A DIELECTRIC SPACER BETWEEN SAID ELECTRODES, SAID SECTION BEING IMPREGNATED WITH A LIQUID DIELECTRIC COMPRISING AT LEAST ONE ESTER HAVING A SUBSTITUENT ON A POSITION SELECTED FROM THE GROUP CONSISTING OF A) ON THE ACID SIDE, ONLY ALKYL CHAINS SUBSTITUTED ON E CARBON ATOM A TO THE ESTER CARBONYL GROUP; AND B) ON THE ALCOHOL SIDE, ALKYL CHAINS SUBSTITUTED ON AT LEAST TWO POSITIONS ON THE CARBON ATOM B TO THE ESTER LINKAGE.
Claim 2
Dependent Claim
88 words
AN ELECTRICAL CAPACITOR COMPRISING A CAPACITANCE SECTION HAVING AT LEAST A PAIR OF ELECTRODES WITH A DIELECTRIC SPACER BETWEEN SAID ELECTRODES, SAID SECTION BEING IMPREGNATED WITH A LIQUID DIELECTRIC COMPRISING AT LEAST ONE ESTER HAVING A SUBSTITUENT ON A POSITION SELECTED FROM THE GROUP CONSISTING OF A) ON THE ACID SIDE, ONLY ALKYL CHAINS SUBSTITUTED ON E CARBON ATOM A TO THE ESTER CARBONYL GROUP; AND B) ON THE ALCOHOL SIDE, ALKYL CHAINS SUBSTITUTED ON AT LEAST TWO POSITIONS ON THE CARBON ATOM B TO THE ESTER LINKAGE.
Claim 3
Dependent Claim
18 words
The capacitor of claim 1 wherein said liquid dielectric comprises at least one substituted ester of the formula
Claim 4
Dependent Claim
18 words
The capacitor of claim 1 wherein said liquid dielectric comprises at least one substituted ester of the formula
Claim 5
Dependent Claim
18 words
The capacitor of claim 1 wherein said liquid dielectric comprises at least one substituted ester of the formula
Claim 6
Dependent Claim
23 words
The capacitor of claim 1 wherein said electrodes are in the form of a thin metallization on each surface of a porous paper.
Claim 7
Dependent Claim
37 words
The capacitor of claim 1 wherein said dielectric spacer is a polyolefin film and wherein at least one of said electrodes is in the form of a metallized layer deposited on a surface of said polyolefin film.
Claim 8
Dependent Claim
11 words
The capacitor of claim 6 wherein said metallized layer is aluminum.
Claim 9
Dependent Claim
12 words
The capacitor of claim 1 wherein said dielectric spacer is polypropylene film.
References Cited (Backward Citations)
US1895376A
Cited
US1966163A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-16 | 1978-06-17 | 1978-12-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-16 | 1982-06-17 | 1982-12-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-16 | 1986-06-17 | 1986-12-17 | $7700.00 | Window Closed / Lapsed |