Patent US4557039A successfully refreshed from Google Patents.
US4557039A
Expired / Lapsed
US
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Method of manufacturing transformer cores
Assignee: Individual
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Filing: 1982-07-20
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Granted: 1985-12-10
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Expires: 2002-07-20
Abstract
Abstract A method of manufacturing transformer cores of either the continuously wound or cut wound type using electrical steel strip having approximately a linear taper. By selecting a suitable taper, a hexagonal (or higher order) approximation of a circular cross section for the legs of the cores is produced. Two complementary core strips can be cut from a single rectangular stock strip in a scrapless manner. The product produced by the method is also disclosed.
Inventors
- 👤 Laurence Manderson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 22:18
CPC Classifications
H; H01; H01F; H01F41/00; H01F41/02; H01F41/0206; H01F41/0233; H01F41/024; H01F41/0213; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49002; Y10T29/4902; Y10T29/49071; Y10T29/49073; Y10T29/49075; Y10T29/49078
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
249 words
A method of manufacturing a transformer core from electrical steel strip wherein said core comprises three frames each of substantially C shape in side view, the frames being arranged substantially 120° apart, comprising: cutting a first strip of increasing constant taper from a minimum width to a maximum width; cutting a second strip having a decreasing constant taper from a maximum width to a minimum width; cutting each strip into a plurality of lamination lengths, each group of three lamination lengths being separated from the adjacent group at an end which is cut at substantially 90° to its longitudinal axis, each said group forming a layer of the core, with three lamination lengths in the group being separated from each other by cuts at substantially 60° to the longitudinal axis, the length dimensions of each layer being predetermined as a function of strip width of the layer such that the length dimensions vary in a non-linear manner from layer to layer; butt joining the ends of two of the lamination lengths cut at substantially 60° to the sides of a third lamination length adjacent an end of the third lamination length cut at substantially 90° to form a lamination layer; and assembling the lamination layers by butt joining the free ends of each lamination layer to form the assembled core such that the cross section of each substantially C-shaped frame is polygonal, and the side elevational profile of the exposed end of each substantially C-shaped frame is substantially wedge-shaped.
Claim 2
Independent Claim
249 words
A method of manufacturing a transformer core from electrical steel strip wherein said core comprises three frames each of substantially C shape in side view, the frames being arranged substantially 120° apart, comprising: cutting a first strip of increasing constant taper from a minimum width to a maximum width; cutting a second strip having a decreasing constant taper from a maximum width to a minimum width; cutting each strip into a plurality of lamination lengths, each group of three lamination lengths being separated from the adjacent group at an end which is cut at substantially 90° to its longitudinal axis, each said group forming a layer of the core, with three lamination lengths in the group being separated from each other by cuts at substantially 60° to the longitudinal axis, the length dimensions of each layer being predetermined as a function of strip width of the layer such that the length dimensions vary in a non-linear manner from layer to layer; butt joining the ends of two of the lamination lengths cut at substantially 60° to the sides of a third lamination length adjacent an end of the third lamination length cut at substantially 90° to form a lamination layer; and assembling the lamination layers by butt joining the free ends of each lamination layer to form the assembled core such that the cross section of each substantially C-shaped frame is polygonal, and the side elevational profile of the exposed end of each substantially C-shaped frame is substantially wedge-shaped.
Claim 3
Dependent Claim
21 words
The method according to claim 1, wherein each of the substantially C-shaped frames is detached from the assembled core for annealing.
Claim 4
Dependent Claim
23 words
The method according to claim 1 or 2, wherein the lamination length comprising each successive lamination layer are assembled on adjacent core frames.
Claim 5
Dependent Claim
23 words
The method according to claim 1 wherein each of the substantially C-shaped frames is detached from the assembled core for a winding operation.
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) | 1988-12-09 | 1989-06-10 | 1989-12-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1992-12-09 | 1993-06-10 | 1993-12-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1996-12-09 | 1997-06-10 | 1997-12-10 | $7700.00 | Window Closed / Lapsed |