US3729653A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Ground conductor continuity checking circuit
Assignee: General Electric Co
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Filing: 1971-11-08
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Granted: 1973-04-24
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Expires: 1991-11-08
Abstract
Abstract In a fail-safe ground conductor continuity monitoring circuit, including means for inserting a low-level monitoring current into a ground conductor and receiver means for sensing if the level of current in the ground conductor is below a predetermined level, and for tripping a system circuit breaker if the current is below that level for a predetermined time, impedance means is connected to the ground conductor to deter the monitoring current from flowing into a stray path shunting the ground conductor.
Inventors
- 👤 L Mankoff
- 👤 T Spinanger
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 18:13
CPC Classifications
H; H02; H02H; H02H11/00; H02H11/001
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
179 words
In a system for supplying electric current through a power circuit including a flexible cable from a fixed source location including a power circuit interrupter to a remote load location in an environment characterized by the presence of undesired stray conductive paths between said locations, a discrete ground conductor extending between said source and load locations, means normally passing a signal current through said ground conductor between said locations, means responsive to presence of said signal current for monitoring the integrity of said ground conductor, said signal responsive means actuating said circuit interrupter to disconnect said power circuit whenever said signal current falls below a predetermined minimum magnitude, and nonlinear impedance means connected between said ground conductor and said stray paths at at least one of said locations, said impedance means being effective to ensure that at least said predetermined minimum magnitude of signal current flows through said ground conductor when the conductor Is intact, whereby said circuit interrupter does not unnecessarily interrupt said power circuit as a result of current flow through stray paths shunting said ground conductor.
Claim 2
Dependent Claim
179 words
In a system for supplying electric current through a power circuit including a flexible cable from a fixed source location including a power circuit interrupter to a remote load location in an environment characterized by the presence of undesired stray conductive paths between said locations, a discrete ground conductor extending between said source and load locations, means normally passing a signal current through said ground conductor between said locations, means responsive to presence of said signal current for monitoring the integrity of said ground conductor, said signal responsive means actuating said circuit interrupter to disconnect said power circuit whenever said signal current falls below a predetermined minimum magnitude, and nonlinear impedance means connected between said ground conductor and said stray paths at at least one of said locations, said impedance means being effective to ensure that at least said predetermined minimum magnitude of signal current flows through said ground conductor when the conductor Is intact, whereby said circuit interrupter does not unnecessarily interrupt said power circuit as a result of current flow through stray paths shunting said ground conductor.
Claim 3
Dependent Claim
31 words
The power system as specified in claim 1 wherein said non-linear impedance means exhibits a high impedance for low signal levels therethrough and a low impedance for high signal levels therethrough.
Claim 4
Dependent Claim
34 words
The power system as specified in claim 2 wherein said load device comprises electrical equipment mounted on a frame and wherein said non-linear impedance means is connected between said ground conductor and said frame.
Claim 5
Dependent Claim
46 words
The power system as specified in claim 2 wherein said system includes a grounding resistor connected between a neutral terminal of said power circuit and said ground conductor at said source location and said non-linear impedance means is connected between said terminal and an earth connection.
Claim 6
Dependent Claim
120 words
The power system as specified in claim 3 wherein said non-linear impedance means comprises a first, second, third, fourth and fifth diodes arranged in a bridge configuration, the cathodes of said first and third diodes being connected together and to the anode of said fifth diode, the anode of said fourth and second diodes being connected together and to the cathode of said fifth diode, the anode of said first diode being connected to the cathode of said fourth diode at a second point, the anode of the third diode being connected to the cathode of said second diode at a third point, said second point being connected to said ground conductor, said third point being connected to said frame.
Claim 7
Dependent Claim
122 words
The power system as specified in claim 4 wherein said non-linear impedance means comprises a first, second, third, fourth and fifth diodes arranged in a bridge configuration, the cathodes of said first and third diodes being connected together and to the anode of said fifth diode, the anode of said fourth and second diodes being connected together and to the cathode of said fifth diode, the anode of said first diode being connected to the cathode of said fourth diode at a second point, the anode of the third diode being connected to the cathode of said second diode at a third point, said second point being connected to said neutral terminal and said third point being connected to said earth connection.
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) | 1976-04-23 | 1976-10-23 | 1977-04-24 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-04-23 | 1980-10-23 | 1981-04-24 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-04-23 | 1984-10-23 | 1985-04-24 | $7700.00 | Window Closed / Lapsed |