Patent US3657604A successfully refreshed from Google Patents.
US3657604A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shock protection device circuit
Assignee: General Electric Co
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Filing: 1971-04-19
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Granted: 1972-04-18
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Expires: 1991-04-19
Abstract
Abstract A ground fault protection circuit utilizing a differential transformer whose output is connected by means of a resistancecapacitance transient surge filter to a silicon controlled rectifier which, when turned on energizes a solenoid which trips a circuit breaker controlling a load circuit. The differential transformer, the resistance, and the capacitance are selected to constitute a circuit whose resonance changes with temperature in such a way as to produce an output which varies in amplitude in a manner closely matching and correcting for the inherent temperature-varying sensitivity of the silicon controlled rectifier.
Inventors
- 👤 Henry G Willard
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 14:29
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/34; H02H3/347; H03; H03K; H03K17/00; H03K17/51; H03K17/56; H03K17/72; H03K17/722; H03K17/723; H03K17/725
Claims Analysis
Total Claims: 23
Claim 1
Independent Claim
309 words
A ground fault protection circuit for a main power circuit which has at least 2 main Circuit conductors comprising: a. current unbalance detection means for detecting an unbalance of instantaneous current values in said main conductors indicating the presence of a ground fault on said main power circuit and for producing an output electric signal in proportion to said current unbalance; b. a solid state electric control device capable of changing sharply from a first non-conducting condition to a second conducting condition upon application thereto of an electrical turn-on signal of predetermined magnitude; c. means connecting said output of said current unbalance detection means to said solid state control device to cause turn-on of said solid state control device upon occurrence of a signal of predetermined magnitude from said current unbalance detection means; d. said solid state control device having the characteristic that the value of said turn-on electric signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-versus-temperature curve; e. means for connecting said solid state control device to the trip member of an automatic electric circuit breaker connected in said main circuit to disconnect said main circuit when said solid state control device is placed in said conducting condition; f. said connecting means connecting said current unbalance detection means to said solid state control device including means for modifying said electric signal produced by said unbalance detection means in accordance with temperature along a magnitude-versus-temperature curve substantially matching said magnitude-versus-temperature curve of said solid state control device, whereby the magnitude of unbalance of currents in said main conductors of said main power circuit required to cause said solid state control device to change from said nonconducting to said conducting condition remains substantially constant regardless of variations in temperature, throughout the operating range of temperature of said circuit.
Claim 2
Dependent Claim
309 words
A ground fault protection circuit for a main power circuit which has at least 2 main Circuit conductors comprising: a. current unbalance detection means for detecting an unbalance of instantaneous current values in said main conductors indicating the presence of a ground fault on said main power circuit and for producing an output electric signal in proportion to said current unbalance; b. a solid state electric control device capable of changing sharply from a first non-conducting condition to a second conducting condition upon application thereto of an electrical turn-on signal of predetermined magnitude; c. means connecting said output of said current unbalance detection means to said solid state control device to cause turn-on of said solid state control device upon occurrence of a signal of predetermined magnitude from said current unbalance detection means; d. said solid state control device having the characteristic that the value of said turn-on electric signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-versus-temperature curve; e. means for connecting said solid state control device to the trip member of an automatic electric circuit breaker connected in said main circuit to disconnect said main circuit when said solid state control device is placed in said conducting condition; f. said connecting means connecting said current unbalance detection means to said solid state control device including means for modifying said electric signal produced by said unbalance detection means in accordance with temperature along a magnitude-versus-temperature curve substantially matching said magnitude-versus-temperature curve of said solid state control device, whereby the magnitude of unbalance of currents in said main conductors of said main power circuit required to cause said solid state control device to change from said nonconducting to said conducting condition remains substantially constant regardless of variations in temperature, throughout the operating range of temperature of said circuit.
Claim 3
Dependent Claim
67 words
A ground fault protection circuit as set forth in claim 1 wherein said means for modifying said electric signal produced by said secondary winding of said differential transformer includes resonant circuit means including inductance means, resistance means, and capacitance means, at least one of said inductance, resistance, and capacitance means varying with temperature to change the magnitude of electric signal applied to said solid state control device.
Claim 4
Dependent Claim
54 words
A ground fault protection circuit as set forth in claim 2 wherein said current unbalance detection means comprises a differential transformer having at least two primary windings thereon and having a secondary winding thereon, a signal being generated in said secondary winding only upon the occurrence of unbalance of currents in said primary windings.
Claim 5
Dependent Claim
37 words
A ground fault protection circuit as set forth in claim 3 wherein said differential transformer includes a magnetically permeable core material whose permeability characteristic changes with temperature to thereby provide said means for modifying said electric signal.
Claim 6
Dependent Claim
50 words
A ground fault protection circuit as set forth in claim 4, said circuit also including resistance and capacitance means connected to and combining with said secondary winding to form a resonant circuit whose resonance point varies with temperature because of said changes in permeability of said differential transformer core material.
Claim 7
Dependent Claim
103 words
A ground fault protection circuit as set forth in claim 5 wherein said resistance means comprises a resistor connected electrically in series between said secondary winding and said solid state control device and said capacitance means comprises a capacitor connected across the output of said secondary winding, said main power source being an alternate-current power source, and said resistor and said capacitor also serving to smooth said output of said secondary winding and further serving to absorb transient surges of said input signal having a time duration less than a predetermined time duration to avoid undesired operation of said solid state control device.
Claim 8
Dependent Claim
54 words
A ground fault protection circuit as set forth in claim 4 wherein said core material of said differential transformer comprises a material whose permeability increases with temperature in the range of temperatures from minus 50*C to about plus 75*C, and wherein said magnitude-versus-temperature change of said solid state control device decreases with increased temperature.
Claim 9
Dependent Claim
33 words
A ground fault protection circuit as set forth in claim 2 wherein said resonant circuit means is substantially out of resonance during the major portion of the operating temperature range of said circuit.
Claim 10
Dependent Claim
38 words
A ground fault protection circuit as set forth in claim 8 wherein said resonant circuit moves farther away from resonance with increasing temperature, to thereby decrease the magnitude of the output signal of said circuit with increasing temperature.
Claim 11
Dependent Claim
113 words
A ground fault protection circuit as set forth in claim 2, said controlled device being operated upon the occurence of a signal of a first polarity from said secondary winding, said circuit including unidirectional conducting means connected across the output of said secondary winding for signals developed by said secondary winding having a polarity opposite from said first polarity, said uni-directional conducting means becoming conducting in said direction only for values of control signal from said secondary winding exceeding a predetermined value higher than said turn-on voltage of said solid state control device and serving to protect said control device from excessively high signals in said opposite polarity developed by said secondary winding.
Claim 12
Dependent Claim
250 words
A solid state electronic control circuit comprising: a. control signal generating means for generating a control signal in response to the occurrence of a predetermined condition; b. a solid state electronic control device capable of changing sharply from a first non-conducting condition to a second conducting condition upon application thereto of an electrical turn-on signal of predetermined magnitude; c. means connecting said output of said signal generating means to said solid state control device so as to cause turn-on of said solid state control device upon the occurence of a signal of predetermined magnitude from said signal generating means; d. said solid state control device having the characteristic that the value of said turn-on signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-vs.-temperature curve; e. means for connecting said solid state control device to a controlled member to be energized upon turn-on of said control device; f. said connecting means connecting said signal generating means to said solid state control device including means for modifying said control signal produced by said signal generating means in accordance with temperature along a predetermined magniture-vs.-temperature curve substantially matching said magnitude-vs.-temperature curve of said solid state control device, whereby the magnitude of signal generated by said signal generating means required to cause said solid state control device to change from said non-conducting to said conducting condition remains substantially constant regardless of variations in temperature throughout the operating range of temperature of said circuit.
Claim 13
Dependent Claim
250 words
A solid state electronic control circuit comprising: a. control signal generating means for generating a control signal in response to the occurrence of a predetermined condition; b. a solid state electronic control device capable of changing sharply from a first non-conducting condition to a second conducting condition upon application thereto of an electrical turn-on signal of predetermined magnitude; c. means connecting said output of said signal generating means to said solid state control device so as to cause turn-on of said solid state control device upon the occurence of a signal of predetermined magnitude from said signal generating means; d. said solid state control device having the characteristic that the value of said turn-on signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-vs.-temperature curve; e. means for connecting said solid state control device to a controlled member to be energized upon turn-on of said control device; f. said connecting means connecting said signal generating means to said solid state control device including means for modifying said control signal produced by said signal generating means in accordance with temperature along a predetermined magniture-vs.-temperature curve substantially matching said magnitude-vs.-temperature curve of said solid state control device, whereby the magnitude of signal generated by said signal generating means required to cause said solid state control device to change from said non-conducting to said conducting condition remains substantially constant regardless of variations in temperature throughout the operating range of temperature of said circuit.
Claim 14
Dependent Claim
64 words
A solid state electronic control circuit as set forth in claim 11 wherein said means for modifying said signal produced by said signal generating means includes resonant circuit means comprising inductance means, resistance means, and capacitance means, at least one of said inductance, resistance, and capacitance means varying with temperature to change the magnitude of electric signal applied to said solid state control device.
Claim 15
Dependent Claim
76 words
An electronic solid state controL circuit as set forth in claim 12 wherein said means for modifying said signal produced by said signal generating means in accordance with temperature includes a transformer having a core material whose permeability increases with increased temperature to change said resonant circuit so as to be farther from its resonant point and to thereby decrease the magnitude of the control signal coupled to said solid state control device with increased temperature.
Claim 16
Dependent Claim
128 words
A solid state electronic control circuit as set forth in claim 12, said solid state control device being operated upon the occurence of a signal of a first polarity from said signal generating means, said circuit including uni-directional conducting means connected across the output of said signal generating means for signals developed by said signal generating means having a polarity opposite from said first polarity, said uni-directional conducting means becoming conducting in said direction only for values of control signal from said signal generating means exceeding a predetermined value higher than the magnitude of turn-on signal required to turn said solid state control device to conducting condition, and serving to protect said control device from excessively high signals generated by said signal generating means of said opposite polarity.
Claim 17
Dependent Claim
54 words
A solid state electronic control circuit as set forth in claim 14, wherein said uni-directional conducting means comprises a first diode, and wherein said circuit includes a Zener diode connected electrically in series with said first diode and having its direction of forward conductivity in a direction opposite to that of said first diode.
Claim 18
Dependent Claim
251 words
A solid state ground fault protection circuit for use in a three-phase electric power system, comprising: a. signal generating means for generating an electric signal in response to and in proportion to a ground fault existing in said three-phase power system; b. a solid state control device capable of changing sharply from a first and non-conducting condition to a second conducting condition upon the application thereto of an electrical turn-on signal of predetermined magnitude; c. means of connecting the output of said signal generating means to said solid state control device to cause turn-on of said solid state control device upon the occurence of a signal of predetermined magnitude from said signal generating means; d. said solid state control device having the characteristic that the value of said turn-on electric signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-vs.-temperature curve; e. means for connecting said solid state control device to the trip member of an automatic electric circuit breaker connected in said main power circuit to disconnect said main power circuit when said solid state control device is placed in said conducting conditions; f. said connecting means including inductance, resistance, and capacitance means forming a resonant circuit, at least one of said inductance, resistance, and capacitance means varying with temperature to change the magnitude of said signal applied to said solid state control device in accordance with temperature, to match the magnitude-vs.-temperature change characteristics of said solid state control device.
Claim 19
Dependent Claim
251 words
A solid state ground fault protection circuit for use in a three-phase electric power system, comprising: a. signal generating means for generating an electric signal in response to and in proportion to a ground fault existing in said three-phase power system; b. a solid state control device capable of changing sharply from a first and non-conducting condition to a second conducting condition upon the application thereto of an electrical turn-on signal of predetermined magnitude; c. means of connecting the output of said signal generating means to said solid state control device to cause turn-on of said solid state control device upon the occurence of a signal of predetermined magnitude from said signal generating means; d. said solid state control device having the characteristic that the value of said turn-on electric signal required to change said device from said non-conducting to said conducting condition varies with temperature along a predetermined magnitude-vs.-temperature curve; e. means for connecting said solid state control device to the trip member of an automatic electric circuit breaker connected in said main power circuit to disconnect said main power circuit when said solid state control device is placed in said conducting conditions; f. said connecting means including inductance, resistance, and capacitance means forming a resonant circuit, at least one of said inductance, resistance, and capacitance means varying with temperature to change the magnitude of said signal applied to said solid state control device in accordance with temperature, to match the magnitude-vs.-temperature change characteristics of said solid state control device.
Claim 20
Dependent Claim
38 words
A solid state ground fault protection circuit as set forth in claim 16 wherein said connecting means includes a transformer having a core material whose permeability changes with temperature to change the resonance characteristics of said resonant circuit.
Claim 21
Dependent Claim
79 words
A solid state ground fault protection circuit as set forth in claim 16 wherein said ground fault detection signal generating means comprises at least three current transformers, there being one such current transformer for each phase of said three-phase power circuit, each of said transformers having a primary with a relatively few winding turns and having a secondary with a relatively high number of winding turns, and means connecting said secondary windings of said current transformers electrically in parallel.
Claim 22
Dependent Claim
89 words
A solid state electronic ground fault protection circuit as set forth in claim 18 wherein said circuit also includes a coupling transformer between said secondary windings of said current transformers and solid state control device, said coupling transformer having its secondary winding arranged to form part of a resonant circuit including resistance, inductance, and capacitance means, said coupling transformer also having its core material comprising a material whose permeability changes with temperature to change the impedance of secondary winding and to change the resonant point of said resonant circuit.
Claim 23
Dependent Claim
68 words
A solid state ground fault protection circuit as set forth in claim 19 wherein said coupling transformer includes a plurality of primary windings each having a different number of turns, and means for selectively connecting said secondary windings of said current transformer to said primary windings of said coupling transformer to change the value of ground fault current required to cause actuation of said solid state control device.
References Cited (Backward Citations)
US3506906A
Cited
US3512045A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-04-18 | 1975-10-18 | 1976-04-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-04-18 | 1979-10-18 | 1980-04-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-04-18 | 1983-10-18 | 1984-04-18 | $7700.00 | Window Closed / Lapsed |