Patent US4346897A successfully refreshed from Google Patents.
Patent US4601765A successfully refreshed from Google Patents.
US4601765A
Expired / Lapsed
US
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Powdered iron core magnetic devices
Assignee: General Electric Co
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Filing: 1983-05-05
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Granted: 1986-07-22
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Expires: 2003-05-05
Abstract
Abstract A compacted powdered iron core utilizes iron powder in the 0.002 to 0.006 mean particle size range which is first coated with an alkali metal silicate and then overcoated with a silicone resin polymer. The treated powder is compressed to approximately 94% of theoretical density and then annealed at approximately 600° C. This results in a core component characterized by overall core losses as low as in conventional laminated cores in A.C. operation.
Inventors
- 👤 Trasimond A. Soileau
- 👤 Lawrence W. Speaker
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-29 21:05
CPC Classifications
C; C08; C08L; C08L39/00; C08L39/04; H; H01; H01F; H01F3/00; H01F3/08; H01F41/00; H01F41/02; H01F41/0206; H01F41/0246
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
45 words
A magnetic core comprising densely packed iron particles having a coating of an alkali metal silicate insulating material and an overcoating of a polymer film selected from the group consisting of silicones, polyimides, fluorocarbons and acrylics, said coating and overcoating providing substantial insulation between particles.
Claim 2
Dependent Claim
45 words
A magnetic core comprising densely packed iron particles having a coating of an alkali metal silicate insulating material and an overcoating of a polymer film selected from the group consisting of silicones, polyimides, fluorocarbons and acrylics, said coating and overcoating providing substantial insulation between particles.
Claim 3
Dependent Claim
20 words
A core as defined in claim 1 wherein said core has been annealed to have a lower electrical loss characteristic.
Claim 4
Dependent Claim
14 words
A core as defined in claim 1 wherein the polymer is a silicone resin.
Claim 5
Dependent Claim
24 words
A core as defined in claim 1 which has been annealed and exhibits relatively low hysteresis losses together with relatively low eddy current losses.
Claim 6
Dependent Claim
93 words
A compacted powdered iron magnetic core component for use in A.C. electrical devices comprising: iron powder consisting of particles sized less than 0.05 inch prior to compaction, the particles of said powder having been coated with alkali metal silicate, overcoated with a polymer film selected from the group consisting of silicones, polyimides, fluorocarbons and acrylics providing insulation between particles, and compacted to at least 90% of theoretical iron density, and the so formed compact having been annealed after said compaction and exhibiting relatively low hysteresis losses together with relatively low eddy current losses.
Claim 7
Dependent Claim
93 words
A compacted powdered iron magnetic core component for use in A.C. electrical devices comprising: iron powder consisting of particles sized less than 0.05 inch prior to compaction, the particles of said powder having been coated with alkali metal silicate, overcoated with a polymer film selected from the group consisting of silicones, polyimides, fluorocarbons and acrylics providing insulation between particles, and compacted to at least 90% of theoretical iron density, and the so formed compact having been annealed after said compaction and exhibiting relatively low hysteresis losses together with relatively low eddy current losses.
Claim 8
Dependent Claim
33 words
A magnetic core component as in claim 5 in which the iron has been annealed to a condition wherein the hysteresis and the eddy current losses are approximately equal at power line frequency.
Claim 9
Dependent Claim
29 words
A magnetic core component as in claim 5 wherein the mean particle size of the iron powder prior to compaction is in the range of 0.002 to 0.006 inch.
Claim 10
Dependent Claim
26 words
A magnetic core component as in claim 5 wherein at least 70% by weight of the particles are in the range of 0.001 to 0.008 inch.
Claim 11
Dependent Claim
21 words
A magnetic core component as in claim 8 which has been compacted to approximately 93% to 95% of theoretical iron density.
Claim 12
Independent Claim
82 words
A method of making a powdered iron magnetic core component for use in A.C. electrical devices comprising: selecting iron powder having particles sized less than 0.05 inch in diameter, mixing an aqueous solution of alkali metal silicate into said powder, drying the powder, mixing a silicone resin dissolved in an organic solvent into said powder, drying the powder to allow the resin to form a thin overcoat on the particles, and pressing the powder to the desired shape for the core component.
Claim 13
Independent Claim
82 words
A method of making a powdered iron magnetic core component for use in A.C. electrical devices comprising: selecting iron powder having particles sized less than 0.05 inch in diameter, mixing an aqueous solution of alkali metal silicate into said powder, drying the powder, mixing a silicone resin dissolved in an organic solvent into said powder, drying the powder to allow the resin to form a thin overcoat on the particles, and pressing the powder to the desired shape for the core component.
Claim 14
Dependent Claim
32 words
The method of claim 10 followed by the step of annealing the core component to a temperature effective for achieving substantial reduction in hysteresis losses without excessive increase in eddy current losses.
Claim 15
Dependent Claim
22 words
The method of claim 11 wherein the selected iron powder has a mean particle size within the range 0.002 to 0.006 inch.
Claim 16
Dependent Claim
42 words
The method of claim 11 wherein the mixture of iron powder and aqueous alkali metal silicate is stirred while blowing air into it until the silicate coated powder becomes free-flowing, and the coated powder is heated to drive off all surface water.
Claim 17
Dependent Claim
21 words
The method of claim 11 wherein the silicone resin is one providing a very thin overcoat of a polyorgano siloxane resin.
Claim 18
Dependent Claim
30 words
The method of claim 14 wherein the silicone resin contains alkyl and aryl groups with a balance of di- and trifunctional groups resulting in high temperature stability and substantial adhesion.
Claim 19
Dependent Claim
26 words
The method of claim 15 wherein the silicone resin is made from a blend of methyl and phenyl trichloro silanes and dimethyl and diphenyl dichloro silanes.
Claim 20
Dependent Claim
18 words
The method of claim 11 wherein the annealing has been to a temperature of at least 500° C.
Claim 21
Dependent Claim
17 words
The method of claim 11 wherein the annealing has been to a temperature of approximately 600° C.
Claim 22
Dependent Claim
14 words
The magnetic core component resulting from the exercise of the method of claim 10.
Claim 23
Dependent Claim
14 words
The magnetic core component resulting from the exercise of the method of claim 11.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1989-07-21 | 1990-01-20 | 1990-07-22 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1993-07-21 | 1994-01-20 | 1994-07-22 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1997-07-21 | 1998-01-20 | 1998-07-22 | $7700.00 | Window Closed / Lapsed |