US3737726A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Earth leakage detector for operating circuit interrupting means
Assignee: Heinemann Electric Ltd
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Filing: 1972-03-28
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Granted: 1973-06-05
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Expires: 1992-03-28
Abstract
Abstract A device for detecting the occurrence of an earth leak fault in a circuit the live and neutral conductors of which constitute first and second primary windings of a core-balance transformer or toroid. On the occurrence of an earth leak fault, a voltage is induced into a secondary winding on the toroid. The secondary voltage is rectified and the rectified voltage charges first and second capacitors. The second capacitor is charges to a lower voltage than the first capacitor. When the first capacitor is fully charged a first switching device is energised. This, in turn, causes a second switching device to be energised allowing the second capacitor to discharge into and operate a circuit breaker or the like. By using two capacitors in the manner described above the toroid is operated in a more efficient manner than has hitherto been possible.
Inventors
- 👤 E Tarchaiski
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 19:43
CPC Classifications
H; H02; H02H; H02H3/00; H02H3/26; H02H3/32; H02H3/33
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
121 words
An earth leakage detector for operating circuit interrupting means, comprising a core balance transformer having a tapped secondary winding, means to rectify the voltages induced in the secondary winding as a result of an unbalance to give a higher voltage and a lower voltage, a first storage device which is charged to a predetermined voltage by the higher rectified voltage, a first switching device which is energized by the first storage device when charged, a second storage device which is charged by the lower rectified voltage, and a second switching device which is energized when the first switching device is energized to enable the second storage device to discharge into and operate said circuit interrupting means via the second switching means.
Claim 2
Dependent Claim
121 words
An earth leakage detector for operating circuit interrupting means, comprising a core balance transformer having a tapped secondary winding, means to rectify the voltages induced in the secondary winding as a result of an unbalance to give a higher voltage and a lower voltage, a first storage device which is charged to a predetermined voltage by the higher rectified voltage, a first switching device which is energized by the first storage device when charged, a second storage device which is charged by the lower rectified voltage, and a second switching device which is energized when the first switching device is energized to enable the second storage device to discharge into and operate said circuit interrupting means via the second switching means.
Claim 3
Dependent Claim
29 words
An earth leakage detector as claimed in claim 1, and a variable voltage divider connected across the first storage device to adjust the sensitivity of the first switching device.
Claim 4
Dependent Claim
23 words
An earth leakage detector as claimed in claim 1, in which the first and second storage devices are charged through a common diode.
Claim 5
Dependent Claim
19 words
An earth leakage detector as claimed in claim 1, in which said first and second storage devices are capacitors.
Claim 6
Dependent Claim
27 words
An earth leakage detector as claimed in claim 4, in which the first storage device has a capacitance substantially less than that of the second storage device.
Claim 7
Dependent Claim
59 words
An earth leakage detector as claimed in claim 1, in which said secondary winding is center tapped and connected to the first storage device in such a way that the entire secondary voltage is applied thereto and connected to the second storage device in such a way that only a center-tapped portion of the secondary voltage is applied thereto.
References Cited (Backward Citations)
US3187225A
Cited
US3512045A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-06-04 | 1976-12-04 | 1977-06-05 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-06-04 | 1980-12-04 | 1981-06-05 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-06-04 | 1984-12-04 | 1985-06-05 | $7700.00 | Window Closed / Lapsed |