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US3772569A
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Ground fault protective system
Assignee: Rucker Co
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Filing: 1972-09-05
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Granted: 1973-11-13
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Expires: 1992-09-05
Abstract
Abstract Ground fault protective system including means for detecting grounding of the neutral conductor independently of the means for detecting ground faults. The secondary winding of a transformer is connected in series with the neutral conductors, and the primary winding of the transformer is energized. Grounding of the neutral conductor is detected by an increase in the primary current.
Inventors
- 👤 P Wible
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 12:09
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/16; H02H3/17; H02H3/26; H02H3/32; H02H3/33; H02H3/331
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
131 words
In a ground fault protective system for use with line and neutral conductors interconnecting a source and a load, the neutral conductor being connected to ground near the source, sensing means for monitoring the flow of current in the line and neutral conductors and providing a fault signal in the event that the current flowing toward the load is not equal to the current flowing toward the source, a transformer having a primary winding and a secondary winding, said secondary winding being connected electrically in series with the neutral conductor, means for energizing the primary winding, means connected to the primary winding for monitoring the flow of current therein and providing an alarm signal if said current exceeds a predetermined level, and circuit means responsive to the fault and alarm signals.
Claim 2
Dependent Claim
131 words
In a ground fault protective system for use with line and neutral conductors interconnecting a source and a load, the neutral conductor being connected to ground near the source, sensing means for monitoring the flow of current in the line and neutral conductors and providing a fault signal in the event that the current flowing toward the load is not equal to the current flowing toward the source, a transformer having a primary winding and a secondary winding, said secondary winding being connected electrically in series with the neutral conductor, means for energizing the primary winding, means connected to the primary winding for monitoring the flow of current therein and providing an alarm signal if said current exceeds a predetermined level, and circuit means responsive to the fault and alarm signals.
Claim 3
Dependent Claim
26 words
A ground fault protective system as in claim 1 wherein the transformer includes a core through which the neutral conductor passes to form the secondary winding.
Claim 4
Dependent Claim
25 words
A ground fault protective system as in claim 1 wherein the transformer includes an additional secondary winding connected electrically in series with the line conductor.
References Cited (Backward Citations)
US3638072A
Cited
US3611035A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-11-12 | 1977-05-14 | 1977-11-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-12 | 1981-05-14 | 1981-11-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-12 | 1985-05-14 | 1985-11-13 | $7700.00 | Window Closed / Lapsed |