US4746891A
Expired / Lapsed
US
⏱️ 0.0 years remaining
High saturation three coil current transformer
Assignee: Schneider Electric USA Inc
•
Filing: 1985-04-19
•
Granted: 1988-05-24
•
Expires: 2005-04-19
Abstract
Abstract A high saturation three coil current transformer for use with electrical apparatus having a U-shaped conductor portion. The current transformer has a ferromagnetic core surrounding one leg of the U-shaped conductor. The core is formed from two U-shaped core portions. A first coil and a second coil are wound on bobbins, with one bobbin being placed around each juncture between the core portions. A third coil is wound about the middle section of one of the U-shaped core portions prior to the core portions being joined. The current transformer is positioned so that the U-shaped conductor surrounds the third coil.
Inventors
- 👤 Henry J. Zylstra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 18:49
CPC Classifications
H; H01; H01F; H01F38/00; H01F38/20; H01F38/22; H01F38/28; H01F38/30
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
149 words
A current transformer and conductor combination, said current transformer producing a current proportional to the current through the conductor, said current transformer and conductor combination comprising: only one generally U-shaped conductor having a first leg and a second leg, the first leg being approximately parallel to the second leg, the current flow in the first leg being opposite to the current flow in the second leg, a generally O-shaped ferromagnetic core surrounding the first leg of said conductor, said core having a first portion located between the first leg and the second leg of said conductor, a first coil and a second coil, each coil surrounding a portion of said core other than the first portion, said first and second coils being electrically connected, and a third coil surrounding the first portion of said core, said third coil being electrically connected in series with said first and second coils.
Claim 2
Dependent Claim
149 words
A current transformer and conductor combination, said current transformer producing a current proportional to the current through the conductor, said current transformer and conductor combination comprising: only one generally U-shaped conductor having a first leg and a second leg, the first leg being approximately parallel to the second leg, the current flow in the first leg being opposite to the current flow in the second leg, a generally O-shaped ferromagnetic core surrounding the first leg of said conductor, said core having a first portion located between the first leg and the second leg of said conductor, a first coil and a second coil, each coil surrounding a portion of said core other than the first portion, said first and second coils being electrically connected, and a third coil surrounding the first portion of said core, said third coil being electrically connected in series with said first and second coils.
Claim 3
Dependent Claim
24 words
A current transformer and conductor combination as claimed in claim 1 wherein said first coil and said second coil are electrically connected in parallel.
Claim 4
Dependent Claim
35 words
A current transformer and conductor combination as claimed in claim 2 wherein said core comprises two generally U-shaped core portions, each core portion having two leg portions and a bight portion connecting the leg portions.
Claim 5
Dependent Claim
25 words
A current transformer and conductor combination as claimed in claim 3 wherein said third coil surrounds the bight portion of one of said core portions.
Claim 6
Dependent Claim
50 words
A current transformer and conductor combination as claimed in claim 4 wherein said current transformer also comprises two bobbins, said first coil and said second coil each being wound about one of said bobbins, each of said bobbins being positioned around a leg portion of each of said core portions.
Claim 7
Dependent Claim
57 words
A current transformer and conductor combination as claimed in claim 1 wherein said third coil is positioned on said core at the location nearest the second leg of said conductor, said third coil creating a magnetic flux that opposes the magnetic flux created by a high level of current flow through the second leg of said conductor.
Claim 8
Dependent Claim
48 words
A current transformer and conductor combination as claimed in claim 6 wherein said conductor is U-shaped having a bight connecting the first leg and the second leg, wherein said conductor bight is nearer to the first portion of said core than to any other portion of said core.
Claim 9
Dependent Claim
31 words
A current transformer and conductor combination as claimed in claim 2 wherein said third coil has greater ampere turns per unit length than either said first coil or said second coil.
Claim 10
Dependent Claim
31 words
A current transformer and conductor combination as claimed in claim 1 wherein none of said first coil, said second coil or said third coil are wound on top of another coil.
Claim 11
Dependent Claim
35 words
A current transformer and conductor combination as claimed in claim 5 wherein said first coil and said second coil and their associated bobbins are each positioned around the juncture of two core portion leg portions.
Claim 12
Dependent Claim
20 words
A current transformer and conductor combination as claimed in claim 1 wherein said conductor passes through said core only once.
References Cited (Backward Citations)
US1748993A
Cited
US1866751A
Cited
US2001897A
Cited
GB439901A
Cited
US2924796A
Cited
US3175175A
Cited
US3201731A
Cited
US3268843A
Cited
US3546565A
Cited
US3996543A
Cited
US4309655A
Cited
US4513274A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1991-05-24 | 1991-11-23 | 1992-05-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1995-05-24 | 1995-11-23 | 1996-05-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1999-05-24 | 1999-11-23 | 2000-05-24 | $7700.00 | Window Closed / Lapsed |