US3663950A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Quad ac power switch with synch
Assignee: Struthers Dunn Inc
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Filing: 1970-01-19
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Granted: 1972-05-16
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Expires: 1990-01-19
Abstract
Abstract Circuit for controlling the energization of an alternatingcurrent load in which the load is electrically isolated from the controlling input. Energization of the load is controlled by a bi-directional thyristor whose gate electrode is energized with a high frequency, square-wave voltage provided by a pair of interconnected NAND gates. A synchronizing signal obtained from the alternating-current power source controls the NAND gates so that they become effective to produce a square-wave signal for the gate electrode of the thyristor as the alternating-current source goes through zero amplitude, and the thyristor again becomes cut off when the current through the load approaches zero, with the result that switching of the load is timed to occur when it will produce the fewest transients and noise throughout the system.
Inventors
- 👤 Peter G Bartlett
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 03:37
CPC Classifications
H; H02; H02M; H02M1/00; H02M1/08; H02M1/083; H03; H03K; H03K17/00; H03K17/13; H03K17/136
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
287 words
A system for selectively controlling the energization of at least one load from an alternating-current source in response to a randomly occurring input so that said load is energized only throughout the presence of said input, comprising in combination, a bi-directional thyristor having first and second anodes and a control gate electrode, first circuit means comprising a series-connected arrangement of said alternating-current source, said load, and the anodes of said thyristor, second means responsive jointly to said alternating-current source and to said input for generating an alternating voltage wave having a frequency which is a multiple of the frequency of said source, said second means comprising two NAND gates each having a first and second input and an output, said output of each gate being connected to a first input of the other gate, said second input of each gate being responsive to said input signal, said output of each said gate being connected to a respeCtive opposite terminal of the primary winding of a saturable transformer and each output also being connected to a source of positive voltage, the secondary winding of said saturable transformer being connected in series with the control gate-second anode circuit of said thyristor, said second means initiating the generation of said alternating voltage wave only upon the first occurrence of a polarity reversal in the wave form of said source subsequent to the onset of said randomly occurring input, means for applying said alternating voltage wave to the control gate-second anode circuit of said thyristor, said second means terminating the generation of said alternating voltage wave only upon the first occurrence of a polarity reversal in the wave form of said source subsequent to the termination of said randomly occurring input.
Claim 2
Independent Claim
287 words
A system for selectively controlling the energization of at least one load from an alternating-current source in response to a randomly occurring input so that said load is energized only throughout the presence of said input, comprising in combination, a bi-directional thyristor having first and second anodes and a control gate electrode, first circuit means comprising a series-connected arrangement of said alternating-current source, said load, and the anodes of said thyristor, second means responsive jointly to said alternating-current source and to said input for generating an alternating voltage wave having a frequency which is a multiple of the frequency of said source, said second means comprising two NAND gates each having a first and second input and an output, said output of each gate being connected to a first input of the other gate, said second input of each gate being responsive to said input signal, said output of each said gate being connected to a respeCtive opposite terminal of the primary winding of a saturable transformer and each output also being connected to a source of positive voltage, the secondary winding of said saturable transformer being connected in series with the control gate-second anode circuit of said thyristor, said second means initiating the generation of said alternating voltage wave only upon the first occurrence of a polarity reversal in the wave form of said source subsequent to the onset of said randomly occurring input, means for applying said alternating voltage wave to the control gate-second anode circuit of said thyristor, said second means terminating the generation of said alternating voltage wave only upon the first occurrence of a polarity reversal in the wave form of said source subsequent to the termination of said randomly occurring input.
Claim 3
Dependent Claim
110 words
The combination of claim 1 in which said second means further includes a bi-stable state flip-flop which is jointly responsive to said alternating-current source and to said input signal, said flip-flop being operated in response to each traversal of the voltage waveform of said source through zero to a respective one of its conditions dependent upon whether said randomly occurring input at such instant is present or absent, said flip-flop when in one of its conditions providing a substantially zero voltage at said second input of each of said gates and in the other of said conditions providing a positive voltage at the second input of each of said gates.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-05-16 | 1975-11-15 | 1976-05-16 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-05-16 | 1979-11-15 | 1980-05-16 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-05-16 | 1983-11-15 | 1984-05-16 | $7700.00 | Window Closed / Lapsed |