US3609459A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable voltage compensated load measuring circuits for controlled closure of single-pole devices
Assignee: General Electric Co
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Filing: 1970-02-24
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Granted: 1971-09-28
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Expires: 1990-02-24
Abstract
Abstract Disclosed is a recloser relay control circuit for use in a traction system wherein a circuit breaker supplies direct current to a load from a bus supplied by a high-voltage source. Upon the occurrence of a fault in the system, the circuit breaker will open to deenergize the load. At this time, the recloser control circuit is inserted into the system to monitor the load resistance and source voltage and to prevent the circuit breaker from reclosing until these monitored parameters attain respective preselected threshold values. The control circuit includes a modified wheatstone bridge circuit utilizing a voltagecompensating subcircuit. The current flowing through the center arm of the bridge, which is a function of the source voltage and the load resistance, and the current flowing through the subcircuit, which is a function of source voltage alone, are algebraically combined in a first detector which provides a ''''close'''' signal when the load resistance is equal to or greater than the preselected threshold value. A second detector is utilized to provide a ''''close'''' signal when the source voltage equals or exceeds the preselected threshold value. The second detector utilizes the current flowing through the subcircuit as its input. Upon the contemporaneous presence of the ''''close'''' signals from each detector the circuit breaker is allowed to reclose thereby reenergizing the load. A diode is provided in the center arm of the bridge to allow the utilization of a low power resistor in the bridge branch paralleling the load resistance.
Inventors
- 👤 Samuel A Thompson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 00:26
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/02; H02H3/06; H02H3/066
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
167 words
In combination with a circuit breaker that normally conducts direct current from a voltage source to an electric power load, a control circuit effective when said circuit breaker has interrupted the flow of current to the load for preventing the circuit breaker from reclosing if the load resistance is lower than a predetermined magnitude, said control circuit comprising: a. first detecting means responsive to the algebraic sum of two input signals, the first of said signals being a function of the source voltage and the load resistance, the second of said signals being a function of the source voltage along whereby the sum of said signals is a function of load resistance, said first detecting means producing a first output signal whenever said sum is no greater than a predetermined value which corresponds to a load resistance of said predetermined magnitude; and b. means operative in response to the production of said first output signal of said first detecting means for enabling said circuit breaker to reclose.
Claim 2
Dependent Claim
167 words
In combination with a circuit breaker that normally conducts direct current from a voltage source to an electric power load, a control circuit effective when said circuit breaker has interrupted the flow of current to the load for preventing the circuit breaker from reclosing if the load resistance is lower than a predetermined magnitude, said control circuit comprising: a. first detecting means responsive to the algebraic sum of two input signals, the first of said signals being a function of the source voltage and the load resistance, the second of said signals being a function of the source voltage along whereby the sum of said signals is a function of load resistance, said first detecting means producing a first output signal whenever said sum is no greater than a predetermined value which corresponds to a load resistance of said predetermined magnitude; and b. means operative in response to the production of said first output signal of said first detecting means for enabling said circuit breaker to reclose.
Claim 3
Dependent Claim
68 words
The combination of claim 1 wherein said control circuit additionally comprises: c. second detecting means responsive to said second input signaL for producing a second output signal whenever said second input signal equals or exceeds a magnitude corresponding to a predetermined level of source voltage, and wherein said enabling means is operative only in response to the contemporaneous presence of both of said first and second output signals.
Claim 4
Dependent Claim
157 words
The combination of claim 1 wherein said first and second input signals are derived by a bridge including first, second and third resistance branches and a fourth resistance branch which is said load, each of said branches having a first and second end, the first ends of said first and second branches being connected to said voltage source a first point, the first ends of said third and fourth branch being connected at a second point, the second end of said first branch and the second end of said third branch being connected at a third point, the second end of said second branch and the second end of said fourth branch being connected at a fourth point, first interconnecting means connecting said third point and said fourth point, second interconnnecting means connecting first point and said second point, said first interconnecting means providing said first input signal, said second interconnecting means providing said second input signal.
Claim 5
Dependent Claim
21 words
The combination of claim 3 wherein said first interconnecting means includes a diode whose cathode is connected to said fourth point.
Claim 6
Dependent Claim
159 words
The combination of claim 2 wherein said first and second inputs signals are derived from a bridge including first, second and third resistance branches and a fourth resistance branch which is said load, each of said branches having a first and second end, the first ends of said first and second branches being connected to said voltage source at a first point, the first ends of said third and fourth branches being connected at a second point, the second end of said first branch and the second end of said third branch being connected at a third point, the second end of said second branch and the second end of said fourth branch being connected at a fourth point, first interconnecting means connecting said third point and said fourth point, second interconnecting means connecting said first point and said second point, said first interconnecting means providing said first input signal, said second interconnecting means providing said second input signal.
Claim 7
Dependent Claim
21 words
The combination of claim 5 wherein said first interconnecting means includes a diode whose cathode is connected to said fourth point.
Claim 8
Dependent Claim
46 words
The combination of claim 6 wherein said second interconnecting means comprises a zener diode poled in opposition to the source voltage, said zener diode having a breakdown voltage lower than the level of source voltage at which the second detecting means produces the second output signal.
Claim 9
Dependent Claim
27 words
The combination of claim 7 wherein means are provided to disconnect said control circuit from said voltage source and said load when said circuit breaker is closed.
Claim 10
Dependent Claim
29 words
The combination as specified in claim 4 wherein means are provided to disconnect the control circuit from said voltage source and said load when said circuit breaker is closed.
Claim 11
Dependent Claim
45 words
The combination of claim 7 wherein said first and second detecting means are magnetic amplifiers and wherein said first input signal is the current flowing through said first interconnecting means and wherein said second input signal is the current flowing through said second interconnecting means.
Claim 12
Dependent Claim
44 words
The combination of claim 4 wherein said first detecting means is a magnetic amplifier and wherein said first input signal is the current flowing through said first interconnecting means and wherein said second input signal is the current flowing through said second interconnecting means.
Claim 13
Dependent Claim
16 words
The combination of claim 10 wherein the resistance of said first and third branches is variable.
Claim 14
Dependent Claim
16 words
The combination of claim 11 wherein the resistance of said first and third branches is variable.
Claim 15
Dependent Claim
16 words
The combination of claim 12 wherein said second interconnecting mEans also comprises a variable resistance element.
Claim 16
Dependent Claim
16 words
The combination of claim 13 wherein said second interconnecting means also comprises a variable resistance element.
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) | 1974-09-27 | 1975-03-29 | 1975-09-28 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-09-27 | 1979-03-29 | 1979-09-28 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-09-27 | 1983-03-29 | 1983-09-28 | $7700.00 | Window Closed / Lapsed |