Patent US3898999A successfully refreshed from Google Patents.
US3740625A
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Electrical capacitors with ester impregnants
Assignee: Sprague Electric Co
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Filing: 1971-11-04
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Granted: 1973-06-19
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Expires: 1991-11-04
Abstract
Abstract Esters are used as impregnants in AC and energy storage capacitors, wherein the esters have alkyl groups substituted around the carbonyl carbon atom to effectively prevent hydrolytic attack thereof by water or hydroxide ions. Appropriate substitution in both the acid and the alcohol moieties insures a hydrolytic stability for the esters produced thereby.
Inventors
- 👤 S Ross
- 👤 M Finkelstein
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 01:41
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
78 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula wherein R1 is a C1-C12 alkyl group; R2 is a member selected from CH3 and H; R3 is a member selected from CH3 and H; R4 is a member selected from CH3, C2H5 and H; R5 is a member selected from CH3, C2H5 and H; and at least one of the groups from R2 to R5 is not H.
Claim 2
Dependent Claim
19 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula
Claim 3
Dependent Claim
19 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula
Claim 4
Dependent Claim
45 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula wherein R1 is a C1-C12 alkyl group; R2 is a member selected from CH3 or H; and R3 is a member selected from CH3 and C2H5.
Claim 5
Dependent Claim
58 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula wherein R1 is a C1-C12 alkyl group; R2 is a member selected from CH3 and H; R3 is a member selected from CH3 and C2H5; and R4 is a member selected from the group consisting of CH3 and C2H5.
Claim 6
Dependent Claim
26 words
The capacitor of claim 1 wherein said liquid dielectric is at least one alkyl substituted ester of the formula wherein R1 is a C1-C12 alkyl group.
Claim 7
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 8
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 9
Dependent Claim
11 words
The capacitor of claim 9 wherein said metallized layer is aluminum.
References Cited (Backward Citations)
US3363156A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-18 | 1976-12-18 | 1977-06-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-18 | 1980-12-18 | 1981-06-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-18 | 1984-12-18 | 1985-06-19 | $7700.00 | Window Closed / Lapsed |