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Patent US3912966A successfully refreshed from Google Patents.
US3912966A
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US
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Incandescent lamp series string having protection against voltage surges
Assignee: General Electric Co
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Filing: 1973-04-30
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Granted: 1975-10-14
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Expires: 1993-04-30
Abstract
Abstract A body of sintered polycrystalline varistor material connected across the filament of an incandescent lamp shunts a transient voltage surge thereby protecting the lamp filament. Additionally, a plurality of such varistor shunt protected incandescent lamps may be serially interconnected in a series string. Upon the opening of a lamp filament in the series string, conduction continues through the varistor element so that the remaining lamps in the string continue to function.
Inventors
- 👤 Jr John D Harnden
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 22:59
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/044; H05; H05B; H05B39/00; H05B39/10; H05B39/105
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
76 words
In a series string of incandescent lamps having a plurality of incandescent lamps therein, each said incandescent lamp having a filament, the improvement which comprises: a plurality of bodies of polycrystalline varistor material, each said body being connected across a corresponding one of said filaments and electrically in parallel therewith for protecting said filaments against voltage surges by instantaneously decreasing impedance in response to increased voltage and by instantaneously increasing impedance in response to decreased voltage.
Claim 2
Dependent Claim
76 words
In a series string of incandescent lamps having a plurality of incandescent lamps therein, each said incandescent lamp having a filament, the improvement which comprises: a plurality of bodies of polycrystalline varistor material, each said body being connected across a corresponding one of said filaments and electrically in parallel therewith for protecting said filaments against voltage surges by instantaneously decreasing impedance in response to increased voltage and by instantaneously increasing impedance in response to decreased voltage.
Claim 3
Dependent Claim
32 words
The improvement of claim 1 wherein said polycrystalline varistor material comprises zinc oxide as a major constituent and a minor constituent selected from the group consisting of other metal oxides and halides.
Claim 4
Dependent Claim
31 words
The improvement of claim 2 wherein said bodies have a varistor Alpha exponent in excess of 10 in the current density range of 10 3 to 102 amperes per square centimeter.
Claim 5
Dependent Claim
54 words
The improvement of claim 1 wherein said bodies have a varistor voltage slightly higher than the voltage drop across said corresponding filaments for preventing leakage current through said bodies when said corresponding filaments are electrically conducting and for providing a low impedance current path through said bodies when said corresponding filaments are electrically open.
Claim 6
Dependent Claim
22 words
The improvement of claim 4 wherein said varistor voltage is approximately equal to 125 percent of the voltage rating of said lamps.
References Cited (Backward Citations)
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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) | 1978-10-13 | 1979-04-14 | 1979-10-14 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-13 | 1983-04-14 | 1983-10-14 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-13 | 1987-04-14 | 1987-10-14 | $7700.00 | Window Closed / Lapsed |