Patent US3660787A successfully refreshed from Google Patents.
US3660787A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Low frequency paper transient filters
Assignee: United States Department of the Navy
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Filing: 1970-08-19
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Granted: 1972-05-02
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Expires: 1990-08-19
Abstract
Abstract Transients in electrical power systems are capable of causing operational malfunctions in, and possible damage to, delicate equipment such as computers and data processing apparatus. The present disclosure is directed to the design of an inductancecapacitance filter which effectively suppresses externallyproduced transients as well as those generated within the load itself.
Inventors
- 👤 Aly A Mahmoud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 22:58
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/005; H02M; H02M1/00; H02M1/14
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
101 words
Apparatus for suppressing power line transients in the frequency range extending from several kilocycles to approximately 400 Hertz, said apparatus being effective to attenuate transients propagating toward a load as well as those originating on the load side and propagating back toward the power line source, said apparatus comprising: a filter network connected between said power line source and said load, said network including a series inductor L and a shunt capacitor C2; a further shunt capacitor C1 interposed between said filter network and said power line source; the forward voltage attenuation characteristic Alpha 1 of said apparatus being given as
Claim 2
Dependent Claim
101 words
Apparatus for suppressing power line transients in the frequency range extending from several kilocycles to approximately 400 Hertz, said apparatus being effective to attenuate transients propagating toward a load as well as those originating on the load side and propagating back toward the power line source, said apparatus comprising: a filter network connected between said power line source and said load, said network including a series inductor L and a shunt capacitor C2; a further shunt capacitor C1 interposed between said filter network and said power line source; the forward voltage attenuation characteristic Alpha 1 of said apparatus being given as
Claim 3
Dependent Claim
17 words
Apparatus according to claim 1 in which said inductor is of the high-permeability laminated iron core type.
Claim 4
Dependent Claim
37 words
Apparatus according to claim 1 in which inductor L has a value of approximately 10 millihenries and capacitor C2 has a value of between 25 and 50 microfarads, yielding a filter cut-off frequency of approximately 220 Hertz.
Claim 5
Dependent Claim
70 words
Apparatus according to claim 1 in which the shunt capacitor C2 is connected to a point on inductor L intermediate the ends thereof, the voltage developed on that portion of the inductor between such point and the end nearest the load being in effect injected into the output of the filter network to compensate for changes in the voltage developed on capacitor C2 in response to variations in said load.
Claim 6
Dependent Claim
39 words
Apparatus according to claim 4 in which the two portions of said inductor lying on opposite sides of said capacitor connection point have a ratio of approximately 3:1, the smallest portion lying on the load side of such point.
References Cited (Backward Citations)
GB890818A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-02 | 1975-11-01 | 1976-05-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-02 | 1979-11-01 | 1980-05-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-02 | 1983-11-01 | 1984-05-02 | $7700.00 | Window Closed / Lapsed |