US1731861A - Magnetic core - Google Patents
Magnetic core Download PDFInfo
- Publication number
- US1731861A US1731861A US352834A US35283429A US1731861A US 1731861 A US1731861 A US 1731861A US 352834 A US352834 A US 352834A US 35283429 A US35283429 A US 35283429A US 1731861 A US1731861 A US 1731861A
- Authority
- US
- United States
- Prior art keywords
- laminations
- silicon steel
- magnetic
- highly permeable
- magnetic core
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 238000003475 lamination Methods 0.000 description 47
- 229910000976 Electrical steel Inorganic materials 0.000 description 24
- 239000000463 material Substances 0.000 description 15
- 238000000576 coating method Methods 0.000 description 12
- 229910001030 Iron–nickel alloy Inorganic materials 0.000 description 8
- 239000011248 coating agent Substances 0.000 description 6
- 230000006698 induction Effects 0.000 description 6
- XUIMIQQOPSSXEZ-UHFFFAOYSA-N Silicon Chemical compound [Si] XUIMIQQOPSSXEZ-UHFFFAOYSA-N 0.000 description 5
- 239000000696 magnetic material Substances 0.000 description 5
- 229910052710 silicon Inorganic materials 0.000 description 5
- 239000010703 silicon Substances 0.000 description 5
- 238000000137 annealing Methods 0.000 description 4
- 238000000034 method Methods 0.000 description 4
- 238000009413 insulation Methods 0.000 description 3
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 description 2
- 230000035699 permeability Effects 0.000 description 2
- 229910000640 Fe alloy Inorganic materials 0.000 description 1
- 238000004534 enameling Methods 0.000 description 1
- UGKDIUIOSMUOAW-UHFFFAOYSA-N iron nickel Chemical compound [Fe].[Ni] UGKDIUIOSMUOAW-UHFFFAOYSA-N 0.000 description 1
- 229910052759 nickel Inorganic materials 0.000 description 1
Images
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
- H01F27/245—Magnetic cores made from sheets, e.g. grain-oriented
Definitions
- My, invention relates to magnetic cores for electrical induction apparatus such as transformers, reactors and the like.
- magnetic cores for alternating current elec-- trical apparatus are formed of superposed sheets'or laminations of magnetic material, the laminations being insulated from each other to prevent excessive eddy currents.
- the magnetic material most extensively used has been silicon steel as this material has good magnetic characteristics which it retains indefinitely.
- the sheets are annealed to reduce eddy current losses in the finished core. It has been found that the annealing process produces an oxide film or coating adhering to the surfaces of silicon steel laminations and that this film will provide satisfactory insulation between the laminations when assembled together in a core. Any film or coating, however,- which is produced on a magnetic laminatiomnot containing silicon is conductive, and when sucli material is used the necessary insulation has to be provided in some other way. This is usu- N ally done by enameling or japanning the surfaces of the individual laminations after they are annealed and before they are assembled.
- the general object oftlie present invention is to provide an improved magnetic core including both silicon steel laminations and laminations .of some more highly permeable material such as nickel iron alloy arranged so that the benefits of the su perior magnetic characteristics of the highly permeable material is secured without any necessary additional expense for insulation.
- FIG. 1 is a diagrammatic view of a transformer having a magnetic core constructed in accordance with the invention
- Fig. 2 is an end view of the core shown in Fig. 1
- Fig. 3 is an enlarged detail view of a small section of Fig. 2.
- the core 10 is formed of superposed laminations of magnetic material which must be insulated from each other to prevent excessive eddy currents.
- the laminations are of-silicon steel and part of them are of highly permeable materialsuch as nickel iron alloy as indicated in Fig. 3.
- the laminations are annealed to improve their magnetic characteristics, the annealing often being done before thelaminations are cut or punched from the original larger sheets.
- the annealmg process produces a thin insulating oxide film or coating on each surface of each of the silicon steel laminations which effectively insulates it from adjacent laminations to prevent appreciable eddy currents between them.
- any film or coating produced on the laminations of nickel iron alloy or other highly permeable material not containing silicon is conductive.
- Each of these laminations is therefore arranged in the core with a silicon steel lamination next to it on each side so that all the highly permeable laminations are insulated by the insulating films produced by the annealing process on the surfaces of the adjacent silicon steel laminations.
- the two kinds of laminations may be arranged alternately in the core as indicated in Fig. 3 in which case, and providing the laminations are all of the same thickness, the magnetic material in the core is half nickel iron alloy or other highly permeable material and half silicon steel.
- a smaller proportion of thedaminations may be of highly permeable material so long as each of them as an annealed silicon steel lamination with its insulating coating next to it on each side. It has been demonstrated that the benefits of the superior magnetic characteristics of the highly permeable laminations are secured in substantially direct proportion to the proportion of this material in the core.
- a magnetic core including superposed laminations, part of said laminations being of silicon steel and part of them being of highly permeable material substantially free of silicon, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings, each of said highly permeable laminations being arranged with a silicon steel lamination next to it on each side.
- a magnetic core including superposed laminations, part of said laminations being of silicon steel and part of them being of highly permeable material substantially free of silicon, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings, the highly permeable laminations being arranged next to silicon steel laminations and insulated therefrom by said coatings.
- a magnetic core including superposed silicon steel and nickel iron alloy laminations, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coating, each of said nickel iron alloy laminations being arranged with a silicon steel lamination nextto it on each side.
- a magnetic core including superposed silicon steel and nickel iron alloy laminations, said laminations being annealed to improve their electrical characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings,,the nickel iron alloy laminations being arranged next to silicon steel laminations and insulated therefrom by said coatings.
- a magnetic core including superposed annealed laminations, the surfaces of part of said laminations having insulating coatings produced by the annealing process, other laminations
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- Engineering & Computer Science (AREA)
- Power Engineering (AREA)
- Soft Magnetic Materials (AREA)
- Manufacturing Cores, Coils, And Magnets (AREA)
Description
H.. F. M RELL 1,731,861
MAGNETIC CORE Oct. 15, 1929.
Filed April 5, 1929 VII'IY -Fig 3. ll Nickel fronflllo y. I'll-ll Silicon Stel.
Inventor Harrg FIXC Rell,
His 'Attorneg.
Patented Oct. 15, 1929 UNITED STATES PATENT OFFICE HARRY I. MORELL, OI PITTSFIELD, MASSACHUSETTS, ASSI GNOR TO GENERAL ELEC- TBIC COMPANY, A CORPORATION 01" mew YORK MAGNETIC CORE Application filed April 5,
My, invention relates to magnetic cores for electrical induction apparatus such as transformers, reactors and the like. Almost all magnetic cores for alternating current elec-- trical apparatus are formed of superposed sheets'or laminations of magnetic material, the laminations being insulated from each other to prevent excessive eddy currents. The magnetic material most extensively used has been silicon steel as this material has good magnetic characteristics which it retains indefinitely. Other magnetic materials havin high permeability, such as nickel iron alloys, have also been used in magnetic cores, the high permeability of these materials making them niore desirable in some cases than silicon steel, but the comparatively high cost of these materials has resulted in their .very limited use.
After either the silicon steel or other mag: netic material has been worked into sheets or laminations of the desired thickness, the sheets are annealed to reduce eddy current losses in the finished core. It has been found that the annealing process produces an oxide film or coating adhering to the surfaces of silicon steel laminations and that this film will provide satisfactory insulation between the laminations when assembled together in a core. Any film or coating, however,- which is produced on a magnetic laminatiomnot containing silicon is conductive, and when sucli material is used the necessary insulation has to be provided in some other way. This is usu- N ally done by enameling or japanning the surfaces of the individual laminations after they are annealed and before they are assembled.
i The additional expense for labor and material still further offsets the advantages of these highly permeable materials as compared with silicon steel and so still further limits their use. The general object oftlie present invention is to provide an improved magnetic core including both silicon steel laminations and laminations .of some more highly permeable material such as nickel iron alloy arranged so that the benefits of the su perior magnetic characteristics of the highly permeable material is secured without any necessary additional expense for insulation.
1929. Serial No. 352,834.
The invention will be better understood from the following description taken in connection with the accompanying drawing in which Fig. 1 is a diagrammatic view of a transformer having a magnetic core constructed in accordance with the invention; Fig. 2 is an end view of the core shown in Fig. 1, and Fig. 3 is an enlarged detail view of a small section of Fig. 2.
The invention will be explained in connection with the transformer shownin Fig. 1, this transformer including a magnetlc core 10 (provided With primary and secondary win ings 11 and 12. As shown in Figs. 2 and 3, the core 10 is formed of superposed laminations of magnetic material which must be insulated from each other to prevent excessive eddy currents. Part of the laminations are of-silicon steel and part of them are of highly permeable materialsuch as nickel iron alloy as indicated in Fig. 3. Before being assembled, the laminations are annealed to improve their magnetic characteristics, the annealing often being done before thelaminations are cut or punched from the original larger sheets. The annealmg process produces a thin insulating oxide film or coating on each surface of each of the silicon steel laminations which effectively insulates it from adjacent laminations to prevent appreciable eddy currents between them.
It has been found, however, that any film or coating produced on the laminations of nickel iron alloy or other highly permeable material not containing silicon is conductive. Each of these laminations is therefore arranged in the core with a silicon steel lamination next to it on each side so that all the highly permeable laminations are insulated by the insulating films produced by the annealing process on the surfaces of the adjacent silicon steel laminations. The two kinds of laminations may be arranged alternately in the core as indicated in Fig. 3 in which case, and providing the laminations are all of the same thickness, the magnetic material in the core is half nickel iron alloy or other highly permeable material and half silicon steel. It will be obvious, however, that a smaller proportion of thedaminations may be of highly permeable material so long as each of them as an annealed silicon steel lamination with its insulating coating next to it on each side. It has been demonstrated that the benefits of the superior magnetic characteristics of the highly permeable laminations are secured in substantially direct proportion to the proportion of this material in the core.
The invention has been explained by describing and illustrating a particular arrangement of magnetic corelaminations but it will be apparent that changes may be made without departing from the spirit and scope of the-invention as covered by the appended claims.
What I claim as new and desire to secure by Letters Patent of the United States, is:
1. In electrical induction apparatus, a magnetic core including superposed laminations, part of said laminations being of silicon steel and part of them being of highly permeable material substantially free of silicon, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings, each of said highly permeable laminations being arranged with a silicon steel lamination next to it on each side.
2. In electrical induction apparatus, a magnetic core including superposed laminations, part of said laminations being of silicon steel and part of them being of highly permeable material substantially free of silicon, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings, the highly permeable laminations being arranged next to silicon steel laminations and insulated therefrom by said coatings.
3. In electrical induction apparatus, a magnetic core including superposed silicon steel and nickel iron alloy laminations, said laminations being annealed to improve their magnetic characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coating, each of said nickel iron alloy laminations being arranged with a silicon steel lamination nextto it on each side.
4. In electrical induction apparatus, a magnetic core including superposed silicon steel and nickel iron alloy laminations, said laminations being annealed to improve their electrical characteristics, whereby the surfaces of said silicon steel laminations are provided with insulating coatings,,the nickel iron alloy laminations being arranged next to silicon steel laminations and insulated therefrom by said coatings. I
5. In electrical induction apparatus, a magnetic core including superposed annealed laminations, the surfaces of part of said laminations having insulating coatings produced by the annealing process, other laminations
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US352834A US1731861A (en) | 1929-04-05 | 1929-04-05 | Magnetic core |
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US352834A US1731861A (en) | 1929-04-05 | 1929-04-05 | Magnetic core |
Publications (1)
Publication Number | Publication Date |
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US1731861A true US1731861A (en) | 1929-10-15 |
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Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
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US352834A Expired - Lifetime US1731861A (en) | 1929-04-05 | 1929-04-05 | Magnetic core |
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Cited By (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442960A (en) * | 1944-08-02 | 1948-06-08 | Lorain Prod Corp | Regulated rectifying system |
US2465798A (en) * | 1946-03-28 | 1949-03-29 | Gen Electric | Magnetic core |
US2489814A (en) * | 1944-08-02 | 1949-11-29 | Lorain Prod Corp | Electric control circuit |
US2777896A (en) * | 1951-06-29 | 1957-01-15 | Bell Telephone Labor Inc | Magnetically loaded composite conductors |
US4205288A (en) * | 1978-10-27 | 1980-05-27 | Westinghouse Electric Corp. | Transformer with parallel magnetic circuits of unequal mean lengths and loss characteristics |
US20150268075A1 (en) * | 2014-03-18 | 2015-09-24 | Rosemount Inc. | Magnetic core configuration for magnetic flowmeters |
EP3246926A1 (en) * | 2016-05-20 | 2017-11-22 | Melexis Technologies SA | Magnetic flux concentrator structure and method for manufacturing the same |
CN109633213A (en) * | 2018-12-14 | 2019-04-16 | 中国电子科技集团公司第四十九研究所 | A kind of current sensor magnetism gathering rings |
-
1929
- 1929-04-05 US US352834A patent/US1731861A/en not_active Expired - Lifetime
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2442960A (en) * | 1944-08-02 | 1948-06-08 | Lorain Prod Corp | Regulated rectifying system |
US2489814A (en) * | 1944-08-02 | 1949-11-29 | Lorain Prod Corp | Electric control circuit |
US2465798A (en) * | 1946-03-28 | 1949-03-29 | Gen Electric | Magnetic core |
US2777896A (en) * | 1951-06-29 | 1957-01-15 | Bell Telephone Labor Inc | Magnetically loaded composite conductors |
US4205288A (en) * | 1978-10-27 | 1980-05-27 | Westinghouse Electric Corp. | Transformer with parallel magnetic circuits of unequal mean lengths and loss characteristics |
US20150268075A1 (en) * | 2014-03-18 | 2015-09-24 | Rosemount Inc. | Magnetic core configuration for magnetic flowmeters |
US9631962B2 (en) * | 2014-03-18 | 2017-04-25 | Rosemount Inc. | Magnetic core configuration for magnetic flowmeters having a plurality of layers of magnetically permeable material |
EP3246926A1 (en) * | 2016-05-20 | 2017-11-22 | Melexis Technologies SA | Magnetic flux concentrator structure and method for manufacturing the same |
CN109633213A (en) * | 2018-12-14 | 2019-04-16 | 中国电子科技集团公司第四十九研究所 | A kind of current sensor magnetism gathering rings |
CN109633213B (en) * | 2018-12-14 | 2021-05-18 | 中国电子科技集团公司第四十九研究所 | Magnetic gathering ring for current sensor |
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