Patent US3846675A successfully refreshed from Google Patents.
US3846675A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Molded case circuit breakers utilizing saturating current transformers
Assignee: Westinghouse Electric Corp
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Filing: 1973-01-30
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Granted: 1974-11-05
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Expires: 1993-01-30
Abstract
Abstract A circuit breaker and control system therefor adapted for use in protecting polyphase electrical transmission systems. Saturating current transformers are used to monitor each phase of the polyphase system. The saturating current transformers provide power to the circuit breaker control system. Information concerning the status of the line current in each phase of the polyphase system is provided in one embodiment by separate line monitors which may be, for instance, air core transformers or Hall generators. In another embodiment of the invention, no separate monitors are required for supplying information to the control system concerning the state of the current level in any of the three phases, since the saturating current transformers are used not only to provide energy for empowering or energizing the control system but also for providing the information concerning the status or level of the current in the phases. This is accomplished by obtaining information concerning the first portion of a sinusoidally shaped wave which is then interpreted electrically to predict the value of the peak of that wave even though the transformer may saturate before the peak is reached. The circuit breaker control system is adapted to provide both instantaneous tripping and time delayed tripping.
Inventors
- 👤 A Shimp
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; H02H1/00; H02H1/0007; H02H1/06; H02H1/063; H02H3/083
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
398 words
An electrical protective system for use with an electrical power system including at least one conductor, comprising: a saturating current transformer means having output terminals and having a predetermined number of secondary turns for monitoring alternating electrical current in said conductor to thereby provide a combination power-intelligence signal at said output terminals, a core resistor means connected across said secondary turns of said saturating current transformer means, said saturating current transformer means being non-saturated within thirty electrical degrees of said alternating current zero so that said power-intelligence signal has a non-saturated position; an electrical control circuit having a set of input terminals for being electrically connected in circuit relationship with said output terminals of said saturating current transformer means, said electrical control circuit having output terminal said electrical control circuit having means therein for anticipating the maximum absolute value of said alternating current during any half cycle thereof when energized by said non-saturated portion of said power-intelligence signal to provide an actuating signal at said output terminal of said electrical control circuit for useful purposes; and electrical protective means including coil means of predetermined resistance value, said protective means having input terminals which are connected in circuit relationship with said output terminAls of said electrical control circuit, said coil means being connected in circuit relationship with said output terminal of said saturating current transformer means, said electrical protective means responding to the presence of said actuating signal from said electrical control circuit to enable said protective means to thereafter be energized by power from said output terminals of said saturating current transformer means being supplied to said coil means to thereby cause a change in the magnitude of said alternating electrical current in said electrical conductor when said alternating electrical current reaches a predetermined value, said predetermined resistance value of said coil means being low compared to said resistance value of said core resistor means and said predetermined number of said secondary turns of said current transformer means being sufficient in magnitude to provide sufficient electrical power to energize said coil means from said current transformer means at a predetermined value within a range of 120 percent of overload or larger for said alternating current in said conductor, said predetermined number of said secondary turns being of such a value as to by necessity cause saturation in said current transformer means within said thirty degrees of current zero.
Claim 2
Dependent Claim
398 words
An electrical protective system for use with an electrical power system including at least one conductor, comprising: a saturating current transformer means having output terminals and having a predetermined number of secondary turns for monitoring alternating electrical current in said conductor to thereby provide a combination power-intelligence signal at said output terminals, a core resistor means connected across said secondary turns of said saturating current transformer means, said saturating current transformer means being non-saturated within thirty electrical degrees of said alternating current zero so that said power-intelligence signal has a non-saturated position; an electrical control circuit having a set of input terminals for being electrically connected in circuit relationship with said output terminals of said saturating current transformer means, said electrical control circuit having output terminal said electrical control circuit having means therein for anticipating the maximum absolute value of said alternating current during any half cycle thereof when energized by said non-saturated portion of said power-intelligence signal to provide an actuating signal at said output terminal of said electrical control circuit for useful purposes; and electrical protective means including coil means of predetermined resistance value, said protective means having input terminals which are connected in circuit relationship with said output terminAls of said electrical control circuit, said coil means being connected in circuit relationship with said output terminal of said saturating current transformer means, said electrical protective means responding to the presence of said actuating signal from said electrical control circuit to enable said protective means to thereafter be energized by power from said output terminals of said saturating current transformer means being supplied to said coil means to thereby cause a change in the magnitude of said alternating electrical current in said electrical conductor when said alternating electrical current reaches a predetermined value, said predetermined resistance value of said coil means being low compared to said resistance value of said core resistor means and said predetermined number of said secondary turns of said current transformer means being sufficient in magnitude to provide sufficient electrical power to energize said coil means from said current transformer means at a predetermined value within a range of 120 percent of overload or larger for said alternating current in said conductor, said predetermined number of said secondary turns being of such a value as to by necessity cause saturation in said current transformer means within said thirty degrees of current zero.
Claim 3
Dependent Claim
60 words
The combination as claimed in claim 1 wherein said electrical protective means comprises a circuit breaker including trip means, said circuit breaker having separable main contacts electrically connected to said electrical conductor, said intelligence signal enabling said trip means to thereby cause actuation of said circuit breaker to thereby open said separable main contacts to thereby interrupt said electrical current.
Claim 4
Dependent Claim
355 words
An electrical protective system for use with an electrical power system having at least one electrical conductor comprising: a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals which signal is related to the magnitude of said electrical current; an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected in circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto; and electrical protective means connected in circuit relationship with said electrical control circuit, said protective means responding to the presence of said intelligence signal and thereby with the aid of said energizing electrical power provided to said electrical control circuit changing the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
Claim 5
Dependent Claim
355 words
An electrical protective system for use with an electrical power system having at least one electrical conductor comprising: a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals which signal is related to the magnitude of said electrical current; an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected in circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto; and electrical protective means connected in circuit relationship with said electrical control circuit, said protective means responding to the presence of said intelligence signal and thereby with the aid of said energizing electrical power provided to said electrical control circuit changing the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
Claim 6
Dependent Claim
71 words
The combination as claimed in claim 3 wherein said electrical protective means comprises an electrical circuit breaker including trip means electrically connected to said electrical control circuit, said circuit breaker having separable main contacts electrically connected to said electrical conductor, said intelligence signal actuating said trip means to thereby actuate said circuit breaker to open said separable main contacts to thereby change the magnitude of said electrical current to substantially zero.
Claim 7
Dependent Claim
40 words
The combination as claimed in claim 4 wherein said trip means comprises means for generally instantaneously actuating said circuit breaker to open said separable main contacts when said predetermined value of said electrical current in said electrical conductor is reached.
Claim 8
Dependent Claim
41 words
The combination as claimed in claim 4 wherein said trip means comprises means for generally delaying for a predetermined time said opening of said separable main contacts after said predetermined value of said electrical current in said electrical conductor is attained.
Claim 9
Dependent Claim
38 words
The combination as claimed in claim 6 wherein said trip means additionally comprises means for generally instantaneously causing said separable main contacts to open when a second predetermined value of electrical current in said electrical conductor is attained.
Claim 10
Dependent Claim
137 words
The combination as claimed in claim 7 comprising a potentiometer with fixed input terminals and a movable output terminal, said fixed terminals of said potentiometer being connected to said output terminals of said current sensing means so that said output intelligence signal may provide a voltage signal thereacross which is proportional to said magnitude of said electrical current in said electrical conductor, said second set of input terminals of said electrical circuit being connected to the movable terminal of said potentiometer and one fixed terminal thereof respectively, so that the level of said intelligence signal provided to said electrical circuit may be adjusted for calibration to thereby select said predetermined value of electrical current in said electrical conductor at which said trip unit will respond to change the magnitude thereof to zero by actuating said circuit breaker.
Claim 11
Dependent Claim
378 words
A circuit breaker for use with an electrical power system having at least one electrical conductor comprising: separable main contacts adapted to be connected to an electrical conductor of an electrical power system, a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals signal which is related to the magnitude of Said electrical current; an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected to circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto; and electrical protective means connected in circuit relationship with said electrical control circuit, said protective means responding to the presence of said intelligence signal and thereby with the aid of said energizing electrical power provided to said electrical control circuit actuating movement of said separable main contact thus changing the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
Claim 12
Dependent Claim
378 words
A circuit breaker for use with an electrical power system having at least one electrical conductor comprising: separable main contacts adapted to be connected to an electrical conductor of an electrical power system, a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals signal which is related to the magnitude of Said electrical current; an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected to circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto; and electrical protective means connected in circuit relationship with said electrical control circuit, said protective means responding to the presence of said intelligence signal and thereby with the aid of said energizing electrical power provided to said electrical control circuit actuating movement of said separable main contact thus changing the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
Claim 13
Dependent Claim
371 words
An electrical protective system for use with an electrical power system having at least one electrical conductor comprising: a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals which signal is related to the magnitude of said electrical current; and an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected in circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto, said intelligence signal and said electrical power thence being providable to electrical protective means adapted to be connected in circuit relationship with a portion of said electrical control circuit, said electrical protective means being of the type which is adapted to respond to the presence of said intelligence signal and said power signal to thereby change the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
Claim 14
Dependent Claim
371 words
An electrical protective system for use with an electrical power system having at least one electrical conductor comprising: a saturating electrical transformer for monitoring alternating electrical current in said electrical conductor and having output terminals which are electrically connected to the input terminals of a full wave bridge rectifier, the magnitude of said alternating current in said electrical conductor during overload current conditions being periodically larger for a certain portion of each half cycle of alternating current than the magnitude of current necessary to saturate said saturating current transformer thereby providing electrical voltage to said rectifier input terminals for only a portion of each half cycle of said alternating current, the output terminals of said full wave bridge rectifier having connected thereacross a filter capacitor, said full wave bridge rectifier providing unidirectional electrical voltage to said filter capacitor, said filter capacitor being adapted to provide pulsating unidirectional electrical power to an electrical control circuit primarily for the purpose of energizing said electrical control circuit; current sensing means having output terminals and being adapted to monitor said time varying electrical current in said electrical conductor to thereby provide an output intelligence signal at said output terminals which signal is related to the magnitude of said electrical current; and an electrical control circuit having first and second sets of input terminals, said first set of input terminals being electrically connected in circuit relationship with said filter capacitor so that said electrical power may be provided to said electrical control circuit for said purpose of energizing said electrical control circuit, said second set of input terminals being electrically connected in circuit relationship with said output terminals of said current sensing means so that said output intelligence signal may be provided to said electrical circuit for supplying said intelligence signal thereto, said intelligence signal and said electrical power thence being providable to electrical protective means adapted to be connected in circuit relationship with a portion of said electrical control circuit, said electrical protective means being of the type which is adapted to respond to the presence of said intelligence signal and said power signal to thereby change the magnitude of said electrical current in said electrical conductor after said electrical current attains a predetermined value.
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) | 1977-11-04 | 1978-05-06 | 1978-11-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-11-04 | 1982-05-06 | 1982-11-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-11-04 | 1986-05-06 | 1986-11-05 | $7700.00 | Window Closed / Lapsed |