US2985855A - Coating for sheet steel in transformer cores - Google Patents
Coating for sheet steel in transformer cores Download PDFInfo
- Publication number
- US2985855A US2985855A US633664A US63366457A US2985855A US 2985855 A US2985855 A US 2985855A US 633664 A US633664 A US 633664A US 63366457 A US63366457 A US 63366457A US 2985855 A US2985855 A US 2985855A
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- Prior art keywords
- coating
- sheet material
- spacing
- laminations
- wound
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Classifications
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F27/00—Details of transformers or inductances, in general
- H01F27/24—Magnetic cores
- H01F27/25—Magnetic cores made from strips or ribbons
-
- H—ELECTRICITY
- H01—ELECTRIC ELEMENTS
- H01F—MAGNETS; INDUCTANCES; TRANSFORMERS; SELECTION OF MATERIALS FOR THEIR MAGNETIC PROPERTIES
- H01F41/00—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties
- H01F41/02—Apparatus or processes specially adapted for manufacturing or assembling magnets, inductances or transformers; Apparatus or processes specially adapted for manufacturing materials characterised by their magnetic properties for manufacturing cores, coils, or magnets
- H01F41/0206—Manufacturing of magnetic cores by mechanical means
- H01F41/0213—Manufacturing of magnetic circuits made from strip(s) or ribbon(s)
-
- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T29/00—Metal working
- Y10T29/49—Method of mechanical manufacture
- Y10T29/49002—Electrical device making
- Y10T29/4902—Electromagnet, transformer or inductor
- Y10T29/49071—Electromagnet, transformer or inductor by winding or coiling
Definitions
- This invention relates in general to wound magnetic cores and in particular to wound magnetic cores provided with an insulating and spacing coating of a predetermined form.
- Electrical steel is sometimes supplied to the transformer manufacturer in either a semifinished state or a fully processed state in the form of large sheets or rolls.
- the material is processed to a size convenient for the core manufacturing process it is given a high temperature anneal in the case of the semifinished state which results in crystal growth in the preferred direction, further purification of the steel and in the case of the fully processed state, a low temperature anneal which results in relief of any strains set up in the material during the manufacturing process.
- the magnetic steel material is in the form of a coil or rolled strip.
- this spacing is formed by inserting shims or spacing elements between the layers prior to annealing. Paper, thread, and other carbon elements have been used as spacing elements.
- Wire has also been used as a spacer but has not produced a uniform degree of spacing and has frequently resulted in grooves in the rolled steel strip. During high temperature annealing the wire frequently fused with the steel strip.
- such a uniform degree of spacing between the laminations of the wound steel strip is obtained by covering the strip with a coating comprising a refractory substance and a bonding agent.
- the exposed surface of this insulating coating is formed into raised areas of spacing elements or spacers.
- the insulating coat ing with spacers can be applied to the top and bottom surfaces of the magnetic sheet material by applying the coating substance to the surfaces and forming this substance into predetermined positioned high areas of spacing elements.
- a further object of this invention is to provide a wound core having a uniform predetermined space between laminations.
- a still further object of this invention is to provide a wound core with removable spacing elements.
- Another object of this invention is to provide an improved method of building wound cores with predetermined spacers between the laminations in the core.
- Fig. 1 is a schematic view illustrating the process of coating a magnetic sheet material for wound cores
- Fig. 2 is an isometric view of a grooved roll
- Fig. 3 is a top view of magnetic sheet material with an insulating coating having spacers
- Fig. 4 is an enlarged cross sectional view of Fig. 3 on line IV-IV.
- magnetic sheet material or a silicon steel strip 11 is covered preferably on both top and bottom surfaces with an adherent coating solution 12 thereon.
- This coating contains a finely divided refractory substance, a bonding agent, and water.
- Any 'known refractory substance such as lime, dolomite, magnesium oxide and silica, and various combinations of the above may be used.
- a preferred bonding agent is carboxymethyl hydroxyethyl cellulose sold by the Hercules Powder Company under the name of CMHEC.
- this invention is not limited to carboxymethyl hydroxyethyl cellulose as other bonding agents such as methyl cellulose, and an alkyd resin or cellulose acetate in suitable organic solvents may be used.
- a preferred coating solution 12 may be prepared .by adding pounds of refractory substance, a mixture of calcium oxide and magnesium oxide, 325 mesh, and 16.7 pounds of carboxymethyl hydroxyethyl cellulose to a sufficient amount of water to form a slurry. These ingredients are then ground in a wet ball mill for several hours until the refractory particles are thoroughly dispersed. It has been found that a suitable coating is obtained when the specific gravity of the solution is substantially 1.07 and its viscosity is 18.5 in a .2 Zahn cup.
- the coating solution 12 is then ready to be applied to the top and bottom broad surfaces of the sheet material 11.
- the resulting unsymmetrical exposed surface of the coating is then formed into relatively high and low areas forming an insulating coating 21 with two different thicknesses.
- the raised areas 22 are of a uniform height with a predetermined cross section and serve as spacing elements.
- the sheet material 11 with its adherent insulating coating 21 is then placed in an oven 16 where evaporation of the excess fluid in the coating occurs. As a result of evaporation the coating is transformed into a solid form.
- the surface of the coating adjacent the sheet material remains adherent and the exposed surface of the coating or surface opposite the adherent surface be comes: nonadherent. condition suitable for handling and cutting as it's insulating coating 21 with spacers 22 will not accidentally flake off.
- a coating with spacers to a sheet material and the following. described method is a preferred one. If the sheet material is obtained in large rolls the coating is applied to its top surface as it unrolls by such means as a tank 13 with a spigot containing coatingmaterial 12. The unrolled sheet material is then passed between two circumferentially grooved coating rolls 14 which form continuous thin insulating coatings 23 and spacing ridges 22 having. a distinctly greater thickness. The roll applying the underneath coating runs immersed in a vat containing the coating material.
- the spacing elements 22 may be varied by changing the width, depth and patterns of the grooves in the rolls.
- a suitable pattern is evenly spaced circumferential grooves 19' of rectangular cross section transversed by another groove 20.
- Diagonal grooves, holes, spiral grooves, and crosshatched grooves are other suitable patterns within the scope of this invention.
- the two coating rolls 14 are set apart at a predetermined distance with a small gap between each roll and the sheet material 11. One roll is placed. in near contact above the sheet material and the other roll is placed in near contact underneath the sheet material. As the sheet material 11' containing the coating 12 passes between the grooved rolls 14 an insulating coating. 21 com prising alternately arranged low areas 23 and high areas of spacers 22 is formed on. the surfaces of the sheet material. The depth of this insulating coating is dependent on the positioning of the rolls 14. Thus, to increase the depth of the coating 21 the rolls 14 are moved farther apart from each other and the sheet material 11.
- the material After being coated the material is passed through an oven 16 which causes the water in the coating solution to evaporate without harming the coating.
- the resulting insulating and spacing coating 21' adheres to the magnetic material 11 so that it may be freely handled in Winding and other forming operations which occur before the final anneal without any substantial amount of the refractory substance rubbing E.
- the strip material is then formed into a wound core 17 and. placed in the annealing furnace 18. It is essential' that the spacers 22- are capable of supporting. the weight of the laminations because these laminations frequently become pliable and weakened during high annealing temperatures. During annealing a portion of the insulating coating 21 on the surfaces of the wound core decomposes freeing aportion of coating 22, the freed portion having performed its function as. a spacer. Another The sheet material 11 is now ina.
- the adherent coating 23 reacts with the surface of the steel to form a final and permanent insulating bond.
- the insulating coating 21 on the surfaces of the wound core decomposes during annealing causing removal of the inert spacers.
- the core 17 in a single operation is provided with a permanent insulating coating and an easily removable spacer which provides uniform spacing between its laminations and consequently may be rapidly assembled into the electrical coils.
- the wound core 17 having been annealed is stress relieved and because of the spacers 22 has uniform space between its laminations and consequently may be rapidly assembled into the electrical coils.
- a core with laminations of a magnetic sheet material said sheet material having thereon a coating comprising a composition of a refractory substance and a bonding agent, a surface of said coating adhering to said sheet material and having a nonadherent surface opposite said adherent surface, saidnonadherent surface having raised spacing areas for maintaining a spacedrelationship between said laminations.
- a wound core with laminations of a magnetic sheet material said sheet material having a coating on a'plurality of surfaces of said laminations, said coating comprising a" composition of a refractory substance and a bonding agent of corboxymethyl hydroxyethyl cellulose, a surface of said coating'adhering to said sheet material and having anonadherent surface removed from said adherent surface, said nonadherent surface having raised spacing areas for supporting said laminations.
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Manufacturing & Machinery (AREA)
- Chemical Treatment Of Metals (AREA)
Description
' May 23, 1961 COATING FOR SHEET STEEL IN TRANSFORMER CORES N. E. STONE Filed Jan. 11, 1957 Z3 23 23 I 1 -v. L T L W W &1 R L 1 T L L 2? I i L 3 93 3 MN j ig Mvm kcrb United States Patent COATING FOR SHEET STEEL IN TRANSFORMER CORES Norman E. Stone, Pittsburgh, Pa., assignor to Allis- Chalmers Manufacturing Company, Milwaukee, Wis.
Filed Jan. 11, 1957, Ser. No. 633,664
2 Claims. (Cl. 336-60) This invention relates in general to wound magnetic cores and in particular to wound magnetic cores provided with an insulating and spacing coating of a predetermined form.
Electrical steel is sometimes supplied to the transformer manufacturer in either a semifinished state or a fully processed state in the form of large sheets or rolls. After the material is processed to a size convenient for the core manufacturing process it is given a high temperature anneal in the case of the semifinished state which results in crystal growth in the preferred direction, further purification of the steel and in the case of the fully processed state, a low temperature anneal which results in relief of any strains set up in the material during the manufacturing process. During the annealing process the magnetic steel material is in the form of a coil or rolled strip. Thus, there is relatively large surface contact between the layers of the magnetic material while in the annealing furnace. Due to the plasticity of the steel at the elevated temperatures associated with the recrystalization anneal, there is a tendency for the associated layers in the assembly to stick together and possibly even weld to one another. It, therefore, becomes desirable to have a coating with a refractory substance between adjacent layers during the high temperature anneal to avoid this sticking, and which will also provide an insulating coating.
It often becomes necessary, during the process of manufacturing wound cores to unwind the annealed rolled strip and wind it around the winding leg of a preformed coil winding. To facilitate this step, it is usually desirable to have a slight degree of spacing between the layers of the wound core prior to annealing it.
In other methods of making wound cores, this spacing is formed by inserting shims or spacing elements between the layers prior to annealing. Paper, thread, and other carbon elements have been used as spacing elements.
These materials burn or char at the annealing temperatures and the carbon thus formed contaminates the annealers. Consequently, the annealers must be frequently cleaned. In addition, these carbon spacers are limited to use in low temperature stress annealing. If used in high temperature recrystalization annealing, the carbon migrates to the wound steel material and defeats the purpose of the recrystalization annealing.
Wire has also been used as a spacer but has not produced a uniform degree of spacing and has frequently resulted in grooves in the rolled steel strip. During high temperature annealing the wire frequently fused with the steel strip.
Increasing the thickness of the insulating coating on the steel strip to act as a spacer has also been attempted. However, when building up large quantities of the coating there is less probability of obtaining a uniform degree of spacing between the laminations of the wound steel strip. Because of the increased area of the coating providing the spacing it is extremely diflicult to obtain a uniform coating surface. Thus a spacer of a noncarbon substance which 2,985,855 Patented May 23, 1961 will not adversely affect the steel strip and which will provide a uniform degree of spacing will overcome the aforementioned objections.
According to this invention such a uniform degree of spacing between the laminations of the wound steel strip is obtained by covering the strip with a coating comprising a refractory substance and a bonding agent. The exposed surface of this insulating coating is formed into raised areas of spacing elements or spacers.
According to the present invention the insulating coat ing with spacers can be applied to the top and bottom surfaces of the magnetic sheet material by applying the coating substance to the surfaces and forming this substance into predetermined positioned high areas of spacing elements.
It is therefore an object of this invention to provide a magnetic sheet material with an insulating coating having raised areas.
A further object of this invention is to provide a wound core having a uniform predetermined space between laminations.
A still further object of this invention is to provide a wound core with removable spacing elements.
Another object of this invention is to provide an improved method of building wound cores with predetermined spacers between the laminations in the core.
Objects and advantages other than those mentioned above will be apparent from the following description: Fig. 1 is a schematic view illustrating the process of coating a magnetic sheet material for wound cores;
Fig. 2 is an isometric view of a grooved roll;
Fig. 3 is a top view of magnetic sheet material with an insulating coating having spacers; and
Fig. 4 is an enlarged cross sectional view of Fig. 3 on line IV-IV.
:In accordance with the present invention, magnetic sheet material or a silicon steel strip 11 is covered preferably on both top and bottom surfaces with an adherent coating solution 12 thereon. This coating contains a finely divided refractory substance, a bonding agent, and water.
Any 'known refractory substance such as lime, dolomite, magnesium oxide and silica, and various combinations of the above may be used. A preferred bonding agent is carboxymethyl hydroxyethyl cellulose sold by the Hercules Powder Company under the name of CMHEC. However, this invention is not limited to carboxymethyl hydroxyethyl cellulose as other bonding agents such as methyl cellulose, and an alkyd resin or cellulose acetate in suitable organic solvents may be used.
A preferred coating solution 12 may be prepared .by adding pounds of refractory substance, a mixture of calcium oxide and magnesium oxide, 325 mesh, and 16.7 pounds of carboxymethyl hydroxyethyl cellulose to a sufficient amount of water to form a slurry. These ingredients are then ground in a wet ball mill for several hours until the refractory particles are thoroughly dispersed. It has been found that a suitable coating is obtained when the specific gravity of the solution is substantially 1.07 and its viscosity is 18.5 in a .2 Zahn cup.
The coating solution 12 is then ready to be applied to the top and bottom broad surfaces of the sheet material 11. The resulting unsymmetrical exposed surface of the coating is then formed into relatively high and low areas forming an insulating coating 21 with two different thicknesses. The raised areas 22 are of a uniform height with a predetermined cross section and serve as spacing elements.
The sheet material 11 with its adherent insulating coating 21 is then placed in an oven 16 where evaporation of the excess fluid in the coating occurs. As a result of evaporation the coating is transformed into a solid form. The surface of the coating adjacent the sheet material remains adherent and the exposed surface of the coating or surface opposite the adherent surface be comes: nonadherent. condition suitable for handling and cutting as it's insulating coating 21 with spacers 22 will not accidentally flake off.
There are several ways of applying a coating, with spacers to a sheet material and the following. described method is a preferred one. If the sheet material is obtained in large rolls the coating is applied to its top surface as it unrolls by such means as a tank 13 with a spigot containing coatingmaterial 12. The unrolled sheet material is then passed between two circumferentially grooved coating rolls 14 which form continuous thin insulating coatings 23 and spacing ridges 22 having. a distinctly greater thickness. The roll applying the underneath coating runs immersed in a vat containing the coating material.
The spacing elements 22 may be varied by changing the width, depth and patterns of the grooves in the rolls. A suitable pattern is evenly spaced circumferential grooves 19' of rectangular cross section transversed by another groove 20. Diagonal grooves, holes, spiral grooves, and crosshatched grooves are other suitable patterns within the scope of this invention.
The two coating rolls 14 are set apart at a predetermined distance with a small gap between each roll and the sheet material 11. One roll is placed. in near contact above the sheet material and the other roll is placed in near contact underneath the sheet material. As the sheet material 11' containing the coating 12 passes between the grooved rolls 14 an insulating coating. 21 com prising alternately arranged low areas 23 and high areas of spacers 22 is formed on. the surfaces of the sheet material. The depth of this insulating coating is dependent on the positioning of the rolls 14. Thus, to increase the depth of the coating 21 the rolls 14 are moved farther apart from each other and the sheet material 11.
After being coated the material is passed through an oven 16 which causes the water in the coating solution to evaporate without harming the coating. The resulting insulating and spacing coating 21' adheres to the magnetic material 11 so that it may be freely handled in Winding and other forming operations which occur before the final anneal without any substantial amount of the refractory substance rubbing E.
The strip material is then formed into a wound core 17 and. placed in the annealing furnace 18. It is essential' that the spacers 22- are capable of supporting. the weight of the laminations because these laminations frequently become pliable and weakened during high annealing temperatures. During annealing a portion of the insulating coating 21 on the surfaces of the wound core decomposes freeing aportion of coating 22, the freed portion having performed its function as. a spacer. Another The sheet material 11 is now ina.
portion of the adherent coating 23 reacts with the surface of the steel to form a final and permanent insulating bond. The insulating coating 21 on the surfaces of the wound core decomposes during annealing causing removal of the inert spacers. Thus the core 17 in a single operation is provided with a permanent insulating coating and an easily removable spacer which provides uniform spacing between its laminations and consequently may be rapidly assembled into the electrical coils. Thus, the wound core 17 having been annealed, is stress relieved and because of the spacers 22 has uniform space between its laminations and consequently may be rapidly assembled into the electrical coils.
While only one embodiment of the present invention has been described, it will be apparenttothose skilled in the art that other modifications may be employed without departing from the spirit of the invention or from the scope of the appended claims.
What is claimed is:
l. A core with laminations of a magnetic sheet material, said sheet material having thereon a coating comprising a composition of a refractory substance and a bonding agent, a surface of said coating adhering to said sheet material and having a nonadherent surface opposite said adherent surface, saidnonadherent surface having raised spacing areas for maintaining a spacedrelationship between said laminations.
2'. A wound core with laminations of a magnetic sheet material, said sheet material having a coating on a'plurality of surfaces of said laminations, said coating comprising a" composition of a refractory substance and a bonding agent of corboxymethyl hydroxyethyl cellulose, a surface of said coating'adhering to said sheet material and having anonadherent surface removed from said adherent surface, said nonadherent surface having raised spacing areas for supporting said laminations.
References Cited in the file of this patent UNITED STATES PATENTS 1,454,323 MacInnes May 8, 1923 2,261,983 Ford Nov. 11, 1941 2,289,339 Brennan July 14, 1942 2,389,497 Gat Nov. 20, 1945 2,390,863 Amidon et a1 Dec. 11, 1945 2,394,047 Elsey et a1. Feb.. 5, 1946 2,410,220v Langworthy Oct. 29, 1946 2,501,349 Nagel 1 Mar. 21, 1950 2,561,462 Compton et al. July 24, 1951. 2,584,564 Ellis Feb. 5, 1952 2,655,101 Newman Oct. 13, 1953 2,670,026 Ungar Feb. 23,- 1954 2,699,195 Weller Jan. 11,v 1955 2,864,065 Horelick et a1. Dec. 9, 1958 FOREIGN PATENTS 587;,374 Great Britain Apr. 23, 1947
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US633664A US2985855A (en) | 1957-01-11 | 1957-01-11 | Coating for sheet steel in transformer cores |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US633664A US2985855A (en) | 1957-01-11 | 1957-01-11 | Coating for sheet steel in transformer cores |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US2985855A true US2985855A (en) | 1961-05-23 |
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| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US633664A Expired - Lifetime US2985855A (en) | 1957-01-11 | 1957-01-11 | Coating for sheet steel in transformer cores |
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| US (1) | US2985855A (en) |
Cited By (10)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3183461A (en) * | 1962-02-05 | 1965-05-11 | Westinghouse Electric Corp | Magnetic core structure with cooling passages therein |
| US3523837A (en) * | 1967-11-06 | 1970-08-11 | Westinghouse Electric Corp | Non-reactive refractory separating coatings for electrical steels |
| US3545078A (en) * | 1966-03-07 | 1970-12-08 | Reynolds Metals Co | Method for making strip conductor coils and parts therefor |
| JPS50356A (en) * | 1973-05-04 | 1975-01-06 | ||
| JPS5020249A (en) * | 1973-06-25 | 1975-03-04 | ||
| JPS5020250A (en) * | 1973-06-25 | 1975-03-04 | ||
| JPS5020248A (en) * | 1973-06-25 | 1975-03-04 | ||
| US4655854A (en) * | 1983-10-27 | 1987-04-07 | Kawasaki Steel Corporation | Grain-oriented silicon steel sheet having a low iron loss free from deterioration due to stress-relief annealing and a method of producing the same |
| US4882834A (en) * | 1987-04-27 | 1989-11-28 | Armco Advanced Materials Corporation | Forming a laminate by applying pressure to remove excess sealing liquid between facing surfaces laminations |
| WO1996027199A1 (en) * | 1995-03-01 | 1996-09-06 | Válcovny Plechu Technotron S.R.O. | Toroidal core |
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| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1454323A (en) * | 1921-11-21 | 1923-05-08 | Macinnes Hugh | Method of and apparatus for making flexible roofing material |
| US2261983A (en) * | 1940-04-10 | 1941-11-11 | Westinghouse Electric & Mfg Co | Bonding of transformer laminations |
| US2289339A (en) * | 1938-08-20 | 1942-07-14 | Joseph B Brennan | Method for making electric devices |
| US2389497A (en) * | 1943-04-14 | 1945-11-20 | Carnegie Illinois Steel Corp | Production of electrical silicon steel |
| US2390863A (en) * | 1941-10-09 | 1945-12-11 | Western Electric Co | Method of making electromagnetic cores |
| US2394047A (en) * | 1941-07-24 | 1946-02-05 | Westinghouse Electric Corp | Process of coating ferrous silicon magnetic material |
| US2410220A (en) * | 1943-12-09 | 1946-10-29 | William P Langworthy | Core lamination and method of production thereof |
| GB587374A (en) * | 1943-11-10 | 1947-04-23 | Westinghouse Electric Int Co | Improvements in or relating to magnetic members and material and to coating compositions for use therewith |
| US2501349A (en) * | 1946-05-10 | 1950-03-21 | Westinghouse Electric Corp | Insulation for magnetic material |
| US2561462A (en) * | 1944-11-30 | 1951-07-24 | Bell Telephone Labor Inc | Electromagnetic core and manufacture thereof |
| US2584564A (en) * | 1950-04-27 | 1952-02-05 | Westinghouse Electric Corp | Magnetic core member |
| US2655101A (en) * | 1945-03-08 | 1953-10-13 | Columbia Ribbon & Carbon | Planographic plate and method of making same |
| US2670026A (en) * | 1948-03-18 | 1954-02-23 | Douglas Aircraft Co Inc | Apparatus for making honeycomb cores for sandwich-type structures |
| US2699195A (en) * | 1951-04-05 | 1955-01-11 | Weller Mfg Company Inc | Apparatus for winding transformer cores |
| US2864065A (en) * | 1955-08-05 | 1958-12-09 | Mc Graw Edison Co | Core construction for transformers |
-
1957
- 1957-01-11 US US633664A patent/US2985855A/en not_active Expired - Lifetime
Patent Citations (15)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US1454323A (en) * | 1921-11-21 | 1923-05-08 | Macinnes Hugh | Method of and apparatus for making flexible roofing material |
| US2289339A (en) * | 1938-08-20 | 1942-07-14 | Joseph B Brennan | Method for making electric devices |
| US2261983A (en) * | 1940-04-10 | 1941-11-11 | Westinghouse Electric & Mfg Co | Bonding of transformer laminations |
| US2394047A (en) * | 1941-07-24 | 1946-02-05 | Westinghouse Electric Corp | Process of coating ferrous silicon magnetic material |
| US2390863A (en) * | 1941-10-09 | 1945-12-11 | Western Electric Co | Method of making electromagnetic cores |
| US2389497A (en) * | 1943-04-14 | 1945-11-20 | Carnegie Illinois Steel Corp | Production of electrical silicon steel |
| GB587374A (en) * | 1943-11-10 | 1947-04-23 | Westinghouse Electric Int Co | Improvements in or relating to magnetic members and material and to coating compositions for use therewith |
| US2410220A (en) * | 1943-12-09 | 1946-10-29 | William P Langworthy | Core lamination and method of production thereof |
| US2561462A (en) * | 1944-11-30 | 1951-07-24 | Bell Telephone Labor Inc | Electromagnetic core and manufacture thereof |
| US2655101A (en) * | 1945-03-08 | 1953-10-13 | Columbia Ribbon & Carbon | Planographic plate and method of making same |
| US2501349A (en) * | 1946-05-10 | 1950-03-21 | Westinghouse Electric Corp | Insulation for magnetic material |
| US2670026A (en) * | 1948-03-18 | 1954-02-23 | Douglas Aircraft Co Inc | Apparatus for making honeycomb cores for sandwich-type structures |
| US2584564A (en) * | 1950-04-27 | 1952-02-05 | Westinghouse Electric Corp | Magnetic core member |
| US2699195A (en) * | 1951-04-05 | 1955-01-11 | Weller Mfg Company Inc | Apparatus for winding transformer cores |
| US2864065A (en) * | 1955-08-05 | 1958-12-09 | Mc Graw Edison Co | Core construction for transformers |
Cited By (12)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3183461A (en) * | 1962-02-05 | 1965-05-11 | Westinghouse Electric Corp | Magnetic core structure with cooling passages therein |
| US3545078A (en) * | 1966-03-07 | 1970-12-08 | Reynolds Metals Co | Method for making strip conductor coils and parts therefor |
| US3523837A (en) * | 1967-11-06 | 1970-08-11 | Westinghouse Electric Corp | Non-reactive refractory separating coatings for electrical steels |
| JPS50356A (en) * | 1973-05-04 | 1975-01-06 | ||
| JPS5316906B2 (en) * | 1973-05-04 | 1978-06-05 | ||
| JPS5020249A (en) * | 1973-06-25 | 1975-03-04 | ||
| JPS5020250A (en) * | 1973-06-25 | 1975-03-04 | ||
| JPS5020248A (en) * | 1973-06-25 | 1975-03-04 | ||
| US4655854A (en) * | 1983-10-27 | 1987-04-07 | Kawasaki Steel Corporation | Grain-oriented silicon steel sheet having a low iron loss free from deterioration due to stress-relief annealing and a method of producing the same |
| US4952253A (en) * | 1983-10-27 | 1990-08-28 | Kawasaki Steel Corporation | Grain-oriented silicon steel sheet having a low iron loss free from deterioration due to stress-relief annealing and a method of producing the same |
| US4882834A (en) * | 1987-04-27 | 1989-11-28 | Armco Advanced Materials Corporation | Forming a laminate by applying pressure to remove excess sealing liquid between facing surfaces laminations |
| WO1996027199A1 (en) * | 1995-03-01 | 1996-09-06 | Válcovny Plechu Technotron S.R.O. | Toroidal core |
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