US3974423A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Differential current protective device
Assignee: Individual
•
Filing: 1974-11-01
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Granted: 1976-08-10
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Expires: 1994-11-01
Abstract
Abstract A differential current protective device comprising a responsive unit, current transformers feeding a polyphase bridge rectifier, a single-phase bridge rectifier connected to the secondary of a differential transformer, a circuit including two resistors connected across the responsive unit, one of said resistors being connected to the single-phase bridge rectifier pole terminals and the other to the polyphase bridge rectifier pole terminals, and a single half-bridge. The device is distinguished from the prior art in that the single half-bridge is connected in a parallel opposed relationship to the polyphase bridge rectifier via a resistor of equal resistance in each arm.
Inventors
- 👤 Evgeny Mefodievich Ulyanitsky
- 👤 Vladimir Semenovich Streltsov
- 👤 Vladimir Ivanovich Belichenko
- 👤 Vladimir Vladimirovich Mikhailov
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 21:15
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/28; H02H3/30; H02H3/307
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
259 words
A differential current protective device for providing a signal when a fault such as a short-circuit occurs within a zone formed by a system which is to be protected while providing no signal when such a fault occurs outside of said zone, comprising a polyphase bridge rectifier, a plurality of current transformers connected to the system forming the zone which is to be protected, said current transformers feeding said polyphase bridge rectifier, a differential current transformer having primary and secondary windings, a single-phase bridge rectifier connected to said secondary winding of said differential transformer, each of said rectifiers having pole terminals, responsive means for providing said signal, a circuit including at least two resistors connected across said responsive means, one of said resistors being connected to said pole terminals of said single-phase bridge rectifier and the other of said resistors being connected to said pole terminals of said polyphase bridge rectifier, and means connected across said other resistor and also connected to said primary winding of said differential current transformer for providing between said resistors a voltage differential of a given minimum magnitude when a fault occurs outside of said zone and a voltage differential of a given maximum value when a fault occurs within the zone to be protected, said responsive means requiring for response a voltage greater than said minimum voltage but substantially less than said maximum voltage but a substantially less than said maximum voltage so that a signal is provided by said responsive means only when a fault occurs within the zone to be protected.
Claim 2
Dependent Claim
259 words
A differential current protective device for providing a signal when a fault such as a short-circuit occurs within a zone formed by a system which is to be protected while providing no signal when such a fault occurs outside of said zone, comprising a polyphase bridge rectifier, a plurality of current transformers connected to the system forming the zone which is to be protected, said current transformers feeding said polyphase bridge rectifier, a differential current transformer having primary and secondary windings, a single-phase bridge rectifier connected to said secondary winding of said differential transformer, each of said rectifiers having pole terminals, responsive means for providing said signal, a circuit including at least two resistors connected across said responsive means, one of said resistors being connected to said pole terminals of said single-phase bridge rectifier and the other of said resistors being connected to said pole terminals of said polyphase bridge rectifier, and means connected across said other resistor and also connected to said primary winding of said differential current transformer for providing between said resistors a voltage differential of a given minimum magnitude when a fault occurs outside of said zone and a voltage differential of a given maximum value when a fault occurs within the zone to be protected, said responsive means requiring for response a voltage greater than said minimum voltage but substantially less than said maximum voltage but a substantially less than said maximum voltage so that a signal is provided by said responsive means only when a fault occurs within the zone to be protected.
Claim 3
Dependent Claim
54 words
The combination of claim 1 and wherein said means connected across said other resistor and to said primary winding of said differential transformer provides at said other resistor an absence of a voltage drop in the event of a fault in the zone to be protected, so as to achieve said maximum voltage differential.
Claim 4
Dependent Claim
67 words
The combination of claim 2 and wherein said means connected across said other resistor and to said primary winding of said differential transformer includes a single half-bridge connected in parallel opposed relationship to said polyphase bridge rectifier by way of a pair of arms which respectively have resistors of equal value therein, said half-bridge having a common point connected to said primary winding of said differential transformer.
Claim 5
Dependent Claim
35 words
The combination of claim 3 and wherein said responsive means includes an integrated circuit amplifer having a non-inverting grounded input and an inverting input formed by said circuit which is connected across said responsive means.
Claim 6
Dependent Claim
33 words
The combination of claim 1 and wherein said responsive means includes an integrated circuit amplifier having a non-inverting grounded input and an inverting input formed by said circuit connected across said responsive means.
References Cited (Backward Citations)
US3573552A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1979-08-10 | 1980-02-09 | 1980-08-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1983-08-10 | 1984-02-09 | 1984-08-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1987-08-10 | 1988-02-09 | 1988-08-10 | $7700.00 | Window Closed / Lapsed |