US3775719A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid insulation for electrical apparatus
Assignee: ABB Inc USA
•
Filing: 1972-04-14
•
Granted: 1973-11-27
•
Expires: 1992-04-14
Abstract
Abstract An improved thermally stable polymeric insulation for use in electrical apparatus and particularly in transformers operated in the presence of transformer oil is a substitute for the conventional cellulosic pressboard, which improved insulation consists of an isotactic polymeric hydrocarbon resin in at least partially crystalline form and cross-linked, 1,2-butadienes and copolymers having a low dielectric constant substantially matching that of the liquid dielectric and having relatively low swelling characteristics when immersed in hot liquid petroleum oil dielectric over an extended period of time.
Inventors
- 👤 G Gainer
- 👤 R Luck
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 17:42
CPC Classifications
H; H01; H01B; H01B13/00; H01B13/06; H01B13/14; H01B3/00; H01B3/02; H01B3/10; H01B3/105; H01B3/18; H01B3/30; H01B3/44; H01B3/441
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
19 words
The electrical apparatus of claim 1 wherein the solid insulating material comprises essentially a thermosetting cross-linked 1,2-polybutadiene hydrocarbon resin.
Claim 2
Dependent Claim
19 words
The electrical apparatus of claim 1 wherein the solid insulating material comprises essentially at least partially crystalline isotactic polystyrene.
Claim 3
Dependent Claim
24 words
The electrical apparatus of claim 1 wherein the solid insulating material comprises essentially a thermoset copolymer of 1,2-polybutadiene hydrocarbon resin and a vinyl monomer.
Claim 4
Dependent Claim
22 words
The apparatus of claim 3 wherein the polystyrene has a crystalline structure of at least about 10 percent of the total resin.
Claim 5
Dependent Claim
20 words
The electrical apparaTus of claim 1 wherein the solid material has a dielectric constant of from about 2.0 to 2.5.
Claim 6
Dependent Claim
17 words
The electrical apparatus of claim 5 wherein the solid material has a dielectric constant of about 2.2.
Claim 7
Dependent Claim
37 words
The electrical apparatus of claim 1 wherein the solid material exhibits a swelling of less than 15 percent by weight over a prolonged period of time when immersed in petroleum oil at a temperature of about 125*C.
Claim 8
Dependent Claim
22 words
The insulation of claim 1 wherein the solid material has a dielectric constant that is substantially that of the petroleum transformer oil.
Claim 9
Dependent Claim
26 words
The insulation of claim 1, wherein the solid insulating material includes fibrous material having a dielectric constant close to that of the resin and the oil.
Claim 10
Dependent Claim
17 words
The insulation of claim 1, wherein fibers of isotactic polystyrene are imbedded in the cross-linked 1,2-polybutadiene resin.
Claim 11
Dependent Claim
17 words
The insulation of claim 1, wherein fibers of polyester resin are imbedded in the cross-linked 1,2-polybutadiene resin.
Claim 12
Dependent Claim
141 words
In a transformer comprising a magnetic core and electrical windings disposed on the legs of the core, and an insulating oil having a dielectric constant of about 2.2 applied to the electrical windings, solid electrical insulation disposed between the electrical windings and the magnetic core, and between portions of the electrical windings, the solid electrical insulation being selected from at least one polymeric material from the group consisting of thermoset 1,2-polybutadiene hydrocarbon resin and copolymers thereof with vinyl monomers, and at least partially crystalline isotactic polystyrene, the polymeric material having a dielectric constant of from about 2.0 to 2.5, and being resistant to swelling when immersed in the insulating oil at temperatures of up to 125*C, whereby improved dielectric strength is exhibited by the combined insulating oil and solid polymeric electrical insulation, and the solid polymeric insulation exhibits good mechanical strength.
Claim 13
Dependent Claim
35 words
The transformer of claim 13, wherein the solid electrical insulation comprises essentially the polymeric material and a fibrous material combined therewith, to provide a strong insulating material capable of withstanding the loads present during service.
Claim 14
Dependent Claim
30 words
The transformer of claim 13, wherein the solid electrical insulation is employed for tubular insulating members interposed between the electrical windings and between the magnetic core and the electrical windings.
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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |