Patent US3795840A successfully refreshed from Google Patents.
US3795840A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Overvoltage protection network
Assignee: National Aeronautics and Space Administration
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Filing: 1972-11-29
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Granted: 1974-03-05
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Expires: 1992-11-29
Abstract
Abstract Electrical equipment to be protected from overvoltage is connected with a possible source of overvoltage via an input conductor. A fuse is connected in series with the input conductor and a spark gap is connected between the input conductor and ground for conducting the overvoltage current to ground and for blowing the fuse to open the circuit to the electrical equipment. A pulse attenuator network is provided between the spark gap and the electrical equipment to be protected for attenuating the pulse of energy passing through the fuse and spark gap prior to blowing of the fuse. The pulse attenuator network includes additional shunt spark gaps, series inductance, and a series connection of a twisted shielded pair of conductors having lowvoltage insulation.
Inventors
- 👤 J Cambra
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 16:56
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/04; H02H9/06
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
155 words
A protection system for an a-c measurement system operating in a high-voltage, high-energy environment comprising: a transducer capable of generating an a-c signal; said transducer having at least two conductors; a ground bus; each of said conductors having a fuse and a spark gap connected in series between said conductor and said ground bus, a high energy-handling, pulse-attenuative, low-pass filter network having an input and an output, said low-pass filter network having a cut-off frequency above the frequency of said a-c signal, said input of said network being coupled in shunt with said spark gap; means for reading out said a-c signal from said transducer; said means for reading out said a-c signal being coupled to said outputs of said low-pass filter network; and said filter network, in the case of a high-voltage, high-energy fault, being able to reduce the energy reaching said means for reading out of a level that can be safely tolerated.
Claim 2
Dependent Claim
155 words
A protection system for an a-c measurement system operating in a high-voltage, high-energy environment comprising: a transducer capable of generating an a-c signal; said transducer having at least two conductors; a ground bus; each of said conductors having a fuse and a spark gap connected in series between said conductor and said ground bus, a high energy-handling, pulse-attenuative, low-pass filter network having an input and an output, said low-pass filter network having a cut-off frequency above the frequency of said a-c signal, said input of said network being coupled in shunt with said spark gap; means for reading out said a-c signal from said transducer; said means for reading out said a-c signal being coupled to said outputs of said low-pass filter network; and said filter network, in the case of a high-voltage, high-energy fault, being able to reduce the energy reaching said means for reading out of a level that can be safely tolerated.
Claim 3
Dependent Claim
163 words
A protection system as set forth in claim 1 wherein said low-pass filter network includes a resistor having first and second terminals, a second spark gap, said first terminal of said resistor connected to said node of said fuse and said first spark gap, said second spark gap connected between said second terminal of said resistor and said ground bus, an inductance having first and second terminals, a third spark gap having first and second terminals, said first terminal of said terminal of said inductance being connected to said node of said resistor and said second spark gap, said first terminal of said third spark gap being connected to said ground bus, means for producing a long distributed capacitance with respect to said ground bus, said means being connected between said second terminal of said inductance and said second terminal of said third spark gap, and said second terminal of said third spark gap comprising an output terminal of said low-pass filter network.
Claim 4
Dependent Claim
34 words
A protection system as set forth in claim 2 wherein said transducer has three conductors and said means for producing a long distributed capacitance comprises a long twisted-pair shielded cable having a low-voltage insulation.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-03-04 | 1977-09-03 | 1978-03-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-03-04 | 1981-09-03 | 1982-03-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-03-04 | 1985-09-03 | 1986-03-05 | $7700.00 | Window Closed / Lapsed |