US3569831A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Over-frequency alarm
Assignee: General Electric Co
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Filing: 1968-08-28
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Granted: 1971-03-09
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Expires: 1988-08-28
Abstract
Abstract An electrical circuit adapted to compare an externally sensed frequency with a reference frequency for giving an indication when the former exceeds the latter via voltage and current phase relationship utilizing a phase shifting inductance, a resonant circuit and a transformer having a core of square loop material, a dual primary winding and an alarm connected to its secondary winding.
Inventors
- 👤 Richard K Davis
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-28 12:01
CPC Classifications
G; G01; G01P; G01P3/00; G01P3/42; G01P3/56; G01P3/60; G05; G05B; G05B1/00; G05B1/01; G05B1/02
Claims Analysis
Total Claims: 2
Claim 1
Independent Claim
115 words
A circuit for comparing an input signal of varying frequency with a reference frequency including a pair of signal channels for accepting said signal simultaneously, a direct current excited square loop core transformer having a pair of differentially connected primary windings, one winding for each said channel and arranged to receive the outputs of said channels; a secondary winding on said transformer; and phase shifting means including means resonating at said reference frequency in one of said channels for displacing its signal 180* from the signal of the other channel whereby an input signal of reference frequency produces an output from said secondary, said secondary winding connected with an indicating device of said reference frequency.
Claim 2
Dependent Claim
115 words
A circuit for comparing an input signal of varying frequency with a reference frequency including a pair of signal channels for accepting said signal simultaneously, a direct current excited square loop core transformer having a pair of differentially connected primary windings, one winding for each said channel and arranged to receive the outputs of said channels; a secondary winding on said transformer; and phase shifting means including means resonating at said reference frequency in one of said channels for displacing its signal 180* from the signal of the other channel whereby an input signal of reference frequency produces an output from said secondary, said secondary winding connected with an indicating device of said reference frequency.
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) | 1974-03-08 | 1974-09-07 | 1975-03-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-03-08 | 1978-09-07 | 1979-03-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-03-08 | 1982-09-07 | 1983-03-09 | $7700.00 | Window Closed / Lapsed |