Patent US3660722A successfully refreshed from Google Patents.
US3660722A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circuit breaker including improved ground fault protective device
Assignee: Westinghouse Electric Corp
•
Filing: 1970-05-07
•
Granted: 1972-05-02
•
Expires: 1990-05-07
Abstract
Abstract A circuit breaker including separable contacts, an operating means for opening and closing the contacts, and a protective relay device for detecting ground faults in an alternating current system when the ground current in the system being protected increases above a predetermined level which for certain values of line currents in the protected system varies with the line currents in the associated system. A current transformer is arranged to provide the energy or power necessary for the output of the device and also to provide a first signal which varies with the ground current in the system and other means is provided for deriving a second signal from the associated system which varies with the line current in the system for with the highest line current in the system with said protective device arranged to respond to both of said signals.
Inventors
- 👤 John T Wilson
- 👤 Joseph C Engel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:33
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/08; H02H3/093; H02H3/26; H02H3/32; H02H3/34; H02H3/347
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
232 words
A circuit breaker for the protection of an alternating current system having at least two line conductors comprising at least one set of separable contacts adapted to be connected to said line conductors, operating means for opening and closing said contacts, first means for obtaining an alternating output current which varies with the ground current in said system, rectifying means having input terminals connected to said first means and output terminals for providing a first unidirectional current output signal which varies with the ground current in said system, second means for deriving a second unidirectional current output signal which varies with the highest current in said line conductors, a level detecting circuit connected to said first and second means to be responsive to said first and second output signals for producing an output which actuates said operating means to open said contacts when said first output signal exceeds a first predetermined value and when said second output signal is less than a second predetermined value, and third means connected between said second means and said level detecting circuit to be responsive to said second output signal for actuating said level detecting circuit to produce the abovementioned output when said second output signal exceeds said second predetermined value and when said first output signal exceeds a value which is greater than said first predetermined value and which increases with said second output signal.
Claim 2
Dependent Claim
232 words
A circuit breaker for the protection of an alternating current system having at least two line conductors comprising at least one set of separable contacts adapted to be connected to said line conductors, operating means for opening and closing said contacts, first means for obtaining an alternating output current which varies with the ground current in said system, rectifying means having input terminals connected to said first means and output terminals for providing a first unidirectional current output signal which varies with the ground current in said system, second means for deriving a second unidirectional current output signal which varies with the highest current in said line conductors, a level detecting circuit connected to said first and second means to be responsive to said first and second output signals for producing an output which actuates said operating means to open said contacts when said first output signal exceeds a first predetermined value and when said second output signal is less than a second predetermined value, and third means connected between said second means and said level detecting circuit to be responsive to said second output signal for actuating said level detecting circuit to produce the abovementioned output when said second output signal exceeds said second predetermined value and when said first output signal exceeds a value which is greater than said first predetermined value and which increases with said second output signal.
Claim 3
Dependent Claim
32 words
The combination as claimed in claim 1 wherein said system includes three line conductors and said circuit breaker includes three sets oF separable contacts which are connected to the respective line conductors.
Claim 4
Dependent Claim
69 words
The combination as claimed in claim 1 wherein an additional means is connected in circuit relation with said level detecting circuit and said operating means to be responsive to the output of said level detecting circuit for producing an additional output which actuates said operating means to open said contacts after a predetermined time delay which is initiated upon the occurrence of the output of said level detecting circuit.
Claim 5
Dependent Claim
79 words
The combination as claimed in claim 1 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional current output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
Claim 6
Dependent Claim
79 words
The combination as claimed in claim 2 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional current output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
Claim 7
Dependent Claim
78 words
The combination as claimed in claim 3 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
Claim 8
Dependent Claim
206 words
A protective relay device for use with an alternating current system having at least two line conductors comprising first means for obtaining an alternating output current which varies with the ground current in said system, rectifying means having input terminals connected to said first means and output terminals for providing a first unidirectional current output signal which varies with the ground current in said system, second means for deriving from said system a second unidirectional current output signal which varies with the current in at least one of said line conductors, a level detecting circuit connected to said first and second means to be responsive to said first and second output signals for producing an output when said first output signal exceeds a first predetermined value and when said second output signal is less than a second predetermined value, and third means connected between said second means and said level detecting circuit to be responsive to said second output signal for actuating said level detecting circuit to produce the above-mentioned output when said second output signal exceeds said second predetermined value and when said first output signal exceeds a value which is greater than said first predetermined value and which increases with said second output signal.
Claim 9
Dependent Claim
206 words
A protective relay device for use with an alternating current system having at least two line conductors comprising first means for obtaining an alternating output current which varies with the ground current in said system, rectifying means having input terminals connected to said first means and output terminals for providing a first unidirectional current output signal which varies with the ground current in said system, second means for deriving from said system a second unidirectional current output signal which varies with the current in at least one of said line conductors, a level detecting circuit connected to said first and second means to be responsive to said first and second output signals for producing an output when said first output signal exceeds a first predetermined value and when said second output signal is less than a second predetermined value, and third means connected between said second means and said level detecting circuit to be responsive to said second output signal for actuating said level detecting circuit to produce the above-mentioned output when said second output signal exceeds said second predetermined value and when said first output signal exceeds a value which is greater than said first predetermined value and which increases with said second output signal.
Claim 10
Dependent Claim
75 words
The combination as claimed in claim 7 wherein said alternating current system is of the three-phase type and includes three line conductors, and an additional means is connected between said second means and said level detecting circuit for deriving a unidirectional output signal which varies with only the highest of the currents in said three line conductors, and said level detecting circuit responds to the last-mentioned output signal and to said second unidirectional output signal.
Claim 11
Dependent Claim
56 words
The combination as claimed in claim 7 wherein an additional means is connected in circuit relation with said level detecting circUit to be responsive to the output of said level detecting circuit for producing an additional output after a predetermined time delay which is initiated upon the occurrence of the output of said level detecting circuit.
Claim 12
Dependent Claim
78 words
The combination as claimed in claim 7 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
Claim 13
Dependent Claim
78 words
The combination as claimed in claim 8 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
Claim 14
Dependent Claim
78 words
The combination as claimed in claim 9 wherein a resistor and an energy storing capacitor is connected in series circuit relationship with one another, the series circuit being connected across the output terminals of said rectifying means to develop said first unidirectional output signal across said resistor which varies with the ground current in said alternating current system and said level detecting circuit is connected to said resistor to be responsive to said first unidirectional current output signal.
References Cited (Backward Citations)
US3440491A
Cited
US3543094A
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 |