US3710187A
Expired / Lapsed
US
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Electromagnetic device having a metal oxide varistor core
Assignee: General Electric Co
•
Filing: 1971-09-30
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Granted: 1973-01-09
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Expires: 1991-09-30
Abstract
Abstract Electromagnetic devices such as inductors and autotransformers having improved suppression to sparking or high voltage peaks at the terminals and between coil windings are provided using certain sintered metal oxide insulators having varistor characteristics. The metal oxide can be employed in conjunction with magnetic core material, as a composite core in such electromagnetic devices.
Inventors
- 👤 J Harnden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-06 18:02
CPC Classifications
H; H01; H01F; H01F27/00; H01F27/40; H01F27/402; H01F27/08; H01F27/22; H01F29/00; H01F29/02; H01F29/025; H01F29/06; H02; H02H; H02H9/00; H02H9/005
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
22 words
An electromagnetic device in accordance with claim 1, where said composite core comprises magnetic material in a sheath of metal oxide varistor.
Claim 2
Dependent Claim
22 words
An electromagnetic device in accordance with claim 1, where said composite core comprises metal oxide varistor in a sheath of magnetic metal.
Claim 3
Dependent Claim
14 words
An electromagnetic device in accordance with claim 1, where the magnetic material is ferrite.
Claim 4
Dependent Claim
18 words
An electromagnetic device in accordance with cLaim 1, where the metal oxide varistor consists essentially of zinc oxide.
Claim 5
Dependent Claim
23 words
An electromagnetic device in accordance with claim 1, having electrodes in ohmic contact with metal oxide varistor and terminals soldered to such electrodes.
Claim 6
Dependent Claim
30 words
An electromagnetic device in accordance with claim 1, where the metal oxide varistor extends beyond the coil winding and serves as a thermal connecting path to an external heat sink.
Claim 7
Dependent Claim
38 words
An inductor in accordance with claim 1, having metal oxide varistor with an Alpha value exceeding 10 as an inner mass within a ferrite sheath, terminal electrodes in ohmic contact with said metal oxide varistor soldered to conductors.
Claim 8
Dependent Claim
48 words
A self-adjusting autotransformer in accordance with claim 1, having a metal oxide varistor layer with an Alpha value exceeding 10 between the coil windings and the magnetic core to provide a conducting path between the autotransformer sweep arm and a conductor in ohmic contact to said varistor layer.
Claim 9
Dependent Claim
51 words
An autotransformer in accordance with claim 1, having a varistor layer between the coil windings on magnetic core, where said varistor layer provides an Alpha greater than 10 and has electrodes in ohmic contact with conducting leads soldered thereto to provide improved spark suppression between said electrodes during high voltage surges.
References Cited (Backward Citations)
US2803570A
Cited
US3307074A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-01-09 | 1976-07-10 | 1977-01-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-01-09 | 1980-07-10 | 1981-01-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-01-09 | 1984-07-10 | 1985-01-09 | $7700.00 | Window Closed / Lapsed |