Patent US3827018A successfully refreshed from Google Patents.
US3827018A
Expired / Lapsed
US
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Power transformer having flux shields surrounding metallic structural members
Assignee: ABB Inc USA
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Filing: 1973-11-02
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Granted: 1974-07-30
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Expires: 1993-11-02
Abstract
Abstract Structural members projecting from the transformer tank are surrounded by flux shields to prevent leakage flux from entering and heating the structural members. The flux shields are constructed of a non-magnetic material which has relatively good electrical conductivity. Current induced into the flux shield by the leakage flux produces flux which counteracts the leakage flux and reduces heating of the structural members.
Inventors
- 👤 M Thomas
- 👤 V Boaz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 06:42
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/34; H01F27/346
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
73 words
A power transformer comprising: a tank assembly; a magnetic core disposed within said tank assembly; a winding assembly inductively coupled to said magnetic core; structural members projecting from the surface of said tank assembly and bracing said core; and flux shields which surround disposed adjacent to said structural members and which effectively reduce the leakage flux entering said structural members, said flux shields being constructed of a relatively good electrical conducting, non-magnetic material.
Claim 2
Dependent Claim
73 words
A power transformer comprising: a tank assembly; a magnetic core disposed within said tank assembly; a winding assembly inductively coupled to said magnetic core; structural members projecting from the surface of said tank assembly and bracing said core; and flux shields which surround disposed adjacent to said structural members and which effectively reduce the leakage flux entering said structural members, said flux shields being constructed of a relatively good electrical conducting, non-magnetic material.
Claim 3
Dependent Claim
38 words
The power transformer of claim 1 wherein the flux shields are constructed of a metallic plate having a thickness which is greater than the skin depth of the plate at the frequency of the flux in the core.
Claim 4
Dependent Claim
20 words
The power transformer of claim 1 wherein the flux shields surround substantially the entire projecting surface of the structural members.
Claim 5
Dependent Claim
17 words
The power transformer of claim 1 wherein the flux shield is constructed of a U-shaped channel member.
Claim 6
Dependent Claim
14 words
The power transformer of claim 1 wherein the flux shield is constructed of aluminum.
Claim 7
Dependent Claim
99 words
A power transformer comprising: a tank assembly; a magnetic core disposed within said tank assembly; a winding assembly inductively coupled to said magnetic core; structural supporting members which project from the surface of said tank assembly and brace said core; and flux shields surrounding substantially the entire projecting surface of said supporTing members; said flux shields being constructed of a metallic plate having a thickness which is greater than the skin depth of the plate at the frequency of the magnetic flux in said core, and said metallic plate being constructed of a relatively good electrical conducting, non-magnetic material.
Claim 8
Dependent Claim
99 words
A power transformer comprising: a tank assembly; a magnetic core disposed within said tank assembly; a winding assembly inductively coupled to said magnetic core; structural supporting members which project from the surface of said tank assembly and brace said core; and flux shields surrounding substantially the entire projecting surface of said supporTing members; said flux shields being constructed of a metallic plate having a thickness which is greater than the skin depth of the plate at the frequency of the magnetic flux in said core, and said metallic plate being constructed of a relatively good electrical conducting, non-magnetic material.
References Cited (Backward Citations)
US2327774A
Cited
US3546358A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-07-29 | 1978-01-28 | 1978-07-30 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-07-29 | 1982-01-28 | 1982-07-30 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-07-29 | 1986-01-28 | 1986-07-30 | $7700.00 | Window Closed / Lapsed |