Patent US3617812A successfully refreshed from Google Patents.
US3617812A
Expired / Lapsed
US
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Protective device for power supply systems
Assignee: Airbus Defence and Space GmbH
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Filing: 1969-11-26
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Granted: 1971-11-02
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Expires: 1989-11-26
Abstract
Abstract A differential protective device for providing short circuit protection for electrical networks such as airborne power supply systems includes a series of current transformers for monitoring the input and output leads of a network and a summing circuit for summing the output signals from the current transformers. Where a fault exists in the network a nonzero current summation will result and a corresponding output voltage produced by the summing circuit. The output voltage is applied to a comparator circuit which is connected to a control unit for controlling a programmed switching operation within the network to locate the fault.
Inventors
- 👤 Burkhard Deter
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 13:55
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/28; H02H3/02; H02H3/04; H02H3/042
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
158 words
A differential protective system for an electrical network comprising a first plurality of current transformers, for monitoring the current flowing in each of the input conductors of the network, each current transformer of said first plurality of current transformers individually monitoring an input conductor to the network and producing an output current in accordance with the current flowing in that input conductor, and further plurality of current transformers for monitoring the current flowing in each of the output conductors of the network, each current transformer of said second plurality of current transformer individually monitoring an output conductor from the network and producing an output current in accordance with the current flowing in that output conductor, summing means for algebraically summing the output currents from said current transformers and for producing an output signal in accordance with that resultant algebraic sum, and control means responsive to said output signal for controlling said network in accordance with a predetermined program.
Claim 2
Dependent Claim
158 words
A differential protective system for an electrical network comprising a first plurality of current transformers, for monitoring the current flowing in each of the input conductors of the network, each current transformer of said first plurality of current transformers individually monitoring an input conductor to the network and producing an output current in accordance with the current flowing in that input conductor, and further plurality of current transformers for monitoring the current flowing in each of the output conductors of the network, each current transformer of said second plurality of current transformer individually monitoring an output conductor from the network and producing an output current in accordance with the current flowing in that output conductor, summing means for algebraically summing the output currents from said current transformers and for producing an output signal in accordance with that resultant algebraic sum, and control means responsive to said output signal for controlling said network in accordance with a predetermined program.
Claim 3
Dependent Claim
32 words
A system as claimed in claim 1 wherein said summing means comprises summing circuit for producing a voltage signal in accordance with the sum of the output currents of said current transformers.
Claim 4
Dependent Claim
28 words
A system as claimed in claim 2 further comprising a comparator circuit connected to the output of said summing circuit and to the input of said control means.
Claim 5
Dependent Claim
15 words
A system as claimed in claim 3 wherein said comparator circuit comprises a Schmitt trigger.
Claim 6
Dependent Claim
26 words
A system as claimed in claim 4 where said control means comprises means for providing selective switching within the network in accordance with a predetermined program.
Claim 7
Independent Claim
16 words
A system as claimed in clam 1 wherein said network includes at least one active element.
Claim 8
Dependent Claim
22 words
A system as claimed in claim 6 wherein the number of input conductors is different from the number of D output conductors.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-11-01 | 1975-05-03 | 1975-11-02 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-01 | 1979-05-03 | 1979-11-02 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-01 | 1983-05-03 | 1983-11-02 | $7700.00 | Window Closed / Lapsed |