US3579163A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Liquid-filled transformer with foamed insulation
Assignee: Westinghouse Electric Corp
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Filing: 1969-09-24
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Granted: 1971-05-18
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Expires: 1989-09-24
Abstract
Abstract Electrical inductive apparatus of the type containing a magnetic core-winding assembly immersed in a liquid-insulating material. The breakdown voltage of predetermined insulating gaps in the apparatus is increased, while maintaining substantially the same dielectric constant across the gap as that of the liquidinsulating material, by disposing an open cell-insulating foam material in the predetermined gaps. The open cells of the foam material are impregnated or filled with the liquid-insulating material, which increases the breakdown voltage in volts per mil across the gap.
Inventors
- 👤 John C Cronin
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 20:25
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/02; H01F27/28; H01F27/30; H01F27/303; H01F27/32; H01F27/324
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
16 words
The electrical inductive apparatus of claim 1 wherein the foamed insulating means is a urethane foam.
Claim 2
Dependent Claim
47 words
The electrical inductive apparatus of claim 1 wherein the magnetic core-winding assembly is of the core-form type, having a plurality of phase winding assemblies disposed on spaced leg portions of the magnetic core, and wherein the foamed insulating means includes members disposed between adjacent phase winding assemblies.
Claim 3
Dependent Claim
23 words
The electrical inductive apparatus of claim 3 wherein the foamed insulating means includes members disposed between the phase winding assemblies and the casing.
Claim 4
Dependent Claim
39 words
The electrical inductive apparatus of claim 3 wherein each phase winding assembly includes concentric high and low voltage windings, and wherein the foamed insulating means includes members disposed in the high-low space between the high and low voltage windings.
Claim 5
Dependent Claim
23 words
The electrical inductive apparatus of claim 1 wherein the foamed insulating means is a urethane foam, and the liquid-insulating means is mineral oil.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |