Patent US3579036A successfully refreshed from Google Patents.
US3579036A
Expired / Lapsed
US
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Crowbar circuit for voltage cutoff with series and shunt switchable means
Assignee: NCR Voyix Corp
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Filing: 1969-01-24
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Granted: 1971-05-18
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Expires: 1989-01-24
Abstract
Abstract A crowbar circuit comprises means sensitive to an overcurrent condition through a load to promptly throw a crowbar across the load, thereby isolating the load from its power supply. To prevent an unreasonable dissipation of power through the crowbar, the same sensing mechanism which throws the crowbar initiates operation of a time delayed mechanism which disconnects the power supply from the crowbar. To further conserve the power supply during the interval following operation of the crowbar and before disconnection of the power supply, the circuit includes energy absorbing means which retards dissipation of power from the power supply.
Inventors
- 👤 Marion B Mccoy
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 17:14
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/02; H02H3/021; H02H3/023; H02H3/08; H02H3/087; H02H3/50; H02H3/52
Claims Analysis
Total Claims: 17
Claim 1
Independent Claim
228 words
A voltage cutoff circuit comprising: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a current sensor, detector means responsive to said current sensor to produce an overcurrent signal, a first switchable device connected directly and without appreciable resistance in series therewith between said first and second circuit means, a second switchable device having a conductive state and being switchable to a nonconductive state, first energy absorbing means, the portions of said first and second circuit means disposed between said first switchable device and said first and second terminals respectively cooperating with said first switchable device to provide a series circuit across said first and second terminals, said series circuit including said second switchable device, said first energy absorbing means and said current sensor, said first switchable device having a nonconductive state and being switchable to a conductive state, first operator means responsive to said overcurrent signal to switch said first switchable device to its conductive state, and second operator means responsive to said overcurrent signal to switch said second switchable device to its nonconductive state.
Claim 2
Dependent Claim
228 words
A voltage cutoff circuit comprising: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a current sensor, detector means responsive to said current sensor to produce an overcurrent signal, a first switchable device connected directly and without appreciable resistance in series therewith between said first and second circuit means, a second switchable device having a conductive state and being switchable to a nonconductive state, first energy absorbing means, the portions of said first and second circuit means disposed between said first switchable device and said first and second terminals respectively cooperating with said first switchable device to provide a series circuit across said first and second terminals, said series circuit including said second switchable device, said first energy absorbing means and said current sensor, said first switchable device having a nonconductive state and being switchable to a conductive state, first operator means responsive to said overcurrent signal to switch said first switchable device to its conductive state, and second operator means responsive to said overcurrent signal to switch said second switchable device to its nonconductive state.
Claim 3
Dependent Claim
14 words
The cutoff circuit of claim 1 wherein said current sensor is a resistance element.
Claim 4
Dependent Claim
93 words
The cutoff circuit of claim 1 wherein said second switchable device is a controlled rectifier having a forward current direction, said second operator means including capacitance means and third circuit means to connect said capacitance means across said controlled rectifier, said third circuit means including a third switchable device, said second operator means including power supply means charging said capacitance means in opposition to the forward current direction of said controlled rectifier, said second operator means including means responsive to said overcurrent signal to switch said third switchable device to a conductive condition.
Claim 5
Dependent Claim
51 words
The cutoff circuit of claim 3 wherein said first and second operator means are simultaneously responsive to said overcurrent signal, said second operator means including time delAy means causing switching of said third switchable device at a time which follows switching of said first switchable device by said first operator means.
Claim 6
Dependent Claim
16 words
The cutoff circuit of claim 4 wherein said third circuit means includes second energy absorbing means.
Claim 7
Dependent Claim
17 words
The cutoff circuit of claim 5 in which said second energy absorbing means comprises an inductance element.
Claim 8
Dependent Claim
64 words
The cutoff circuit of claim 4 wherein said first energy absorbing means includes an energy accumulator having a limited ability to accumulate energy, said second operator means including means to adjust said time delay means to cause switching of said third switchable device to its conductive state prior to the time the ability of said energy accumulator means to accumulate energy has been exhausted.
Claim 9
Dependent Claim
16 words
The cutoff circuit of claim 7 wherein said first energy absorbing means comprises an inductance element.
Claim 10
Dependent Claim
120 words
A voltage cutoff circuit comprising, in combination: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a controlled rectifier having a gate, power supply means to energize said gate to switch said controlled rectifier, disabling means to block energization of said gate interposed between said power supply means and said gate, a manual switch, and means responsive to closure of said manual switch to enable said disabling means.
Claim 11
Dependent Claim
120 words
A voltage cutoff circuit comprising, in combination: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a controlled rectifier having a gate, power supply means to energize said gate to switch said controlled rectifier, disabling means to block energization of said gate interposed between said power supply means and said gate, a manual switch, and means responsive to closure of said manual switch to enable said disabling means.
Claim 12
Dependent Claim
165 words
The cutoff circuit of claim 9 wherein one of said first and second circuit means includes a current sensor, detector means responsive to said current sensor to produce an overcurrent signal, a first switchable device connected between said first and second circuit means, the portions of said circuit means disposed between said first switchable device and said first and second terminals respectively cooperating with said first switchable device to provide a series circuit across said first and second terminals, said first switchable device having a nonconductive state and being switchable to a conductive state, first operator means responsive to said overcurrent signal to switch said first switchable device to its conductive state, means responsive to opening of said manual switch to produce a turnoff signal, said detector means including a signal inverter, said signal inverter responsive to said turnoff signal to simulate an overcurrent signal, said first operator means responsive to said simulated overcurrent signal to switch said first switchable device to its conductive state.
Claim 13
Dependent Claim
19 words
The cutoff circuit of claim 10 including means to inhibit said turnoff signal as said manual switch is closed.
Claim 14
Dependent Claim
212 words
A voltage cutoff circuit comprising: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a current sensor, detector means responsive to said current sensor to produce an overcurrent signal, a first switchable device connected between said first and second circuit means, a second switchable device having a conductive state and being switchable to a nonconductive state, the portions of said first and second circuit means disposed between said first switchable device and said first and second terminals respectively cooperating with said first switchable device to provide a series circuit across said first and second terminals, said series circuit including said second switchable device and first energy absorbing means, said first switchable device having a nonconductive state and being switchabLe to a conductive state, first operator means responsive to said overcurrent signal to switch said first switchable device to its conductive state, and second operator means responsive to said overcurrent signal to switch said second switchable device to its nonconductive state.
Claim 15
Dependent Claim
212 words
A voltage cutoff circuit comprising: first and second terminals for connection to a source of voltage, third and fourth terminals for connection to a load, first circuit means connected to said first and third terminals for providing a current path therebetween, second circuit means connected to said second and fourth terminals for providing a current path therebetween, one of said first and second circuit means including a current sensor, detector means responsive to said current sensor to produce an overcurrent signal, a first switchable device connected between said first and second circuit means, a second switchable device having a conductive state and being switchable to a nonconductive state, the portions of said first and second circuit means disposed between said first switchable device and said first and second terminals respectively cooperating with said first switchable device to provide a series circuit across said first and second terminals, said series circuit including said second switchable device and first energy absorbing means, said first switchable device having a nonconductive state and being switchabLe to a conductive state, first operator means responsive to said overcurrent signal to switch said first switchable device to its conductive state, and second operator means responsive to said overcurrent signal to switch said second switchable device to its nonconductive state.
Claim 16
Dependent Claim
16 words
The cutoff circuit of claim 12 wherein said current sensor is disposed in said series circuit.
Claim 17
Dependent Claim
14 words
The cutoff circuit of claim 13 wherein said current sensor is a resistance element.
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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) | 1974-05-17 | 1974-11-16 | 1975-05-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-05-17 | 1978-11-16 | 1979-05-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-05-17 | 1982-11-16 | 1983-05-18 | $7700.00 | Window Closed / Lapsed |