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US3723813A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Alarm circuit for monitoring the primary winding of a neutralizing transformer and its grounding connection
Assignee: Individual
•
Filing: 1972-01-17
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Granted: 1973-03-27
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Expires: 1992-01-17
Abstract
Abstract A remote alarm and indicating circuit for the primary of a neutralizing transformer utilizing an oscillator to produce balanced opposing signals in the primary and grounding circuits. These signals also flow through the coils of a differential relay in such a manner that if the ground circuit opens or if there is an appreciable change in its impedance or resistance, on the order of 5 percent or more, the differential relay will operate denoting such an occurrence.
Inventors
- 👤 G Allen
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 09:34
CPC Classifications
H; H02; H02H; H02H1/00; H02H1/0007; H02H1/003; H02H11/00; H02H11/001; H02H9/00; H02H9/08
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
131 words
A monitor circuit for monitoring the primary winding ground circuit of a neutralizing transformer comprising a differential relay having a first and a second winding and means operable upon an unbalance in current flowing through said first and second windings. A local oscillator having a first and a second output circuit, means for connecting said first output circuit in series with said first winding and said primary winding and said second output circuit in series with said second winding and said primary winding so as to produce a substantially equal and opposite current flow in said first and said second windings and an unbalance in the current flow in said first and said second windings upon a change in the impedance of the primary winding ground circuit of the neutralizing transformer.
Claim 2
Dependent Claim
131 words
A monitor circuit for monitoring the primary winding ground circuit of a neutralizing transformer comprising a differential relay having a first and a second winding and means operable upon an unbalance in current flowing through said first and second windings. A local oscillator having a first and a second output circuit, means for connecting said first output circuit in series with said first winding and said primary winding and said second output circuit in series with said second winding and said primary winding so as to produce a substantially equal and opposite current flow in said first and said second windings and an unbalance in the current flow in said first and said second windings upon a change in the impedance of the primary winding ground circuit of the neutralizing transformer.
Claim 3
Dependent Claim
50 words
A monitor circuit as set forth in claim 1, wherein said ground circuit includes a local ground connected to one side of the primary winding and a remote ground connected to the other side of the primary winding, said remote ground being located outside the influence of the local ground.
Claim 4
Dependent Claim
38 words
A monitor circuit as set forth in claim 2, wherein said means for connecting said first and said second windings includes separate circuits including a balancing potentiometer connected in series with one of said first and second windings.
Claim 5
Dependent Claim
154 words
A remote monitor circuit for monitoring the primary winding ground circuit of a substation neutralizing transformer comprising a local substation ground circuit for said primary winding and a remote ground circuit for said primary winding, said remote ground circuit having a ground established outside the influence of the substation ground, a differential relay having a first and a second winding, first means connecting Said first winding in series with the neutralizing transformer primary winding, second means connecting said second winding in series with the neutralizing transformer primary winding, means for applying to said first and second winding a current flow to produce opposing forces, said relay including a switch adapted to be operated from a first position corresponding to substantially equal and opposite opposing forces to a second position corresponding to an unbalance of the opposing forces resulting from a change in the impedance of the primary winding ground circuit of the neutralizing transformer.
Claim 6
Dependent Claim
154 words
A remote monitor circuit for monitoring the primary winding ground circuit of a substation neutralizing transformer comprising a local substation ground circuit for said primary winding and a remote ground circuit for said primary winding, said remote ground circuit having a ground established outside the influence of the substation ground, a differential relay having a first and a second winding, first means connecting Said first winding in series with the neutralizing transformer primary winding, second means connecting said second winding in series with the neutralizing transformer primary winding, means for applying to said first and second winding a current flow to produce opposing forces, said relay including a switch adapted to be operated from a first position corresponding to substantially equal and opposite opposing forces to a second position corresponding to an unbalance of the opposing forces resulting from a change in the impedance of the primary winding ground circuit of the neutralizing transformer.
Claim 7
Dependent Claim
19 words
A remote monitor circuit as set forth in claim 4, wherein said differential relay is remote from said substation.
Claim 8
Dependent Claim
84 words
A remote monitor circuit as set forth in claim 4, wherein said remote ground circuit comprises a cable connected between one end of the primary winding and a remote ground point, said local ground circuit comprising a direct connection to the substation ground from the other end of the primary winding, said cable being connected in series with the ground circuit of said primary winding by said first means and in parallel with the ground circuit of said primary winding by said second means.
References Cited (Backward Citations)
US3641393A
Cited
US3676737A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |