Patent US3710293A successfully refreshed from Google Patents.
US3710293A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Insulating member for transformer coils
Assignee: ABB Inc USA
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Filing: 1972-03-30
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Granted: 1973-01-09
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Expires: 1992-03-30
Abstract
Abstract U-shaped channels extend around the edges of the coils of shellform power transformers. The channels are constructed of layers of crepe paper and pressboard with at least one layer of crepe paper separating adjacent layers of pressboard. An adhesive is used to bond the layers together. In one embodiment, the edges of the channels are scarfed to form a scarfed joint with an adjacent channel.
Inventors
- 👤 G Lazor
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 21:44
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/28; H01F27/32; H01F27/324
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
76 words
Electrical inductive apparatus having a winding, said winding comprising a plurality of pancake-type substantially rectangular coils, insulating members disposed around the edges of said coils, each of said insulating members having a U-shaped crosssection with an axial side and two radial sides, said axial and radial sides being constructed of a laminated insulating material comprising at least two layers of crepe paper separated by a layer of pressboard with an adhesive material applied to said layerS.
Claim 2
Dependent Claim
76 words
Electrical inductive apparatus having a winding, said winding comprising a plurality of pancake-type substantially rectangular coils, insulating members disposed around the edges of said coils, each of said insulating members having a U-shaped crosssection with an axial side and two radial sides, said axial and radial sides being constructed of a laminated insulating material comprising at least two layers of crepe paper separated by a layer of pressboard with an adhesive material applied to said layerS.
Claim 3
Dependent Claim
26 words
The electrical inductive apparatus of claim 1 wherein the insulating members having a U-shaped cross-section are curved to conform to the shape of a coil corner.
Claim 4
Dependent Claim
39 words
The electrical inductive apparatus of claim 1 wherein the insulating members have first and second ends, said first and seconds ends having a scarfed pattern with the length of the layers varying across the thickness of the insulating material.
Claim 5
Dependent Claim
25 words
The electrical inductive apparatus of claim 1 wherein the adhesive material is a thermoplastic resin and the crepe paper has about 25 crimps per inch.
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) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |