US3775591A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Oven heater element control circuit
Assignee: Motors Liquidation Co
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Filing: 1972-12-26
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Granted: 1973-11-27
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Expires: 1992-12-26
Abstract
Abstract A switching circuit for a heating element including a power triac in series with the heater element between one line of an alternating current source and neutral. The power triac is controlled from a pilot triac connected in series with an RC network between the control electrode of the power triac and neutral. The pilot triac is triggered a short time interval after the zero crossing of the AC source and the capacitor is alternately charged in opposite directions with the charge accumulation of the capacitor being utilized to trigger the power triac.
Inventors
- 👤 R Gould
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-22 22:20
CPC Classifications
H; H03; H03K; H03K17/00; H03K17/13; H03K17/136; G; G05; G05D; G05D23/00; G05D23/19; G05D23/1906; G05D23/1913; G05D23/1917; G05D23/20; G05D23/24; H05; H05B; H05B1/00; H05B1/02; H05B1/0227; H05B1/0252; H05B1/0258; H05B1/0261; H05B1/0263
Claims Analysis
Total Claims: 4
Claim 1
Independent Claim
156 words
A circuit for controlling the current flow through a load from an A.C. voltage source having first and second line terminals and a grounded neutral terminal comprising; first and second gate controlled bilateral semi-conductor switch means having first and second load terminals and a control gate terminal; means connecting the load terminals of said first switch means in series with said load between said first and second line terminals of said source; a series resistance capacitance network connecting the gate terminal of said first switch means to said first load terminal of said second switch means, means connecting said second load terminal of said second switch means to said neutral terminal of said source; neutral referenced control circuit means for developing a series of output trigger pulses synchronized with the zero crossover voltage point of said source; and means applying the output of the control circuit means to the gate terminal of said second switch means.
Claim 2
Dependent Claim
156 words
A circuit for controlling the current flow through a load from an A.C. voltage source having first and second line terminals and a grounded neutral terminal comprising; first and second gate controlled bilateral semi-conductor switch means having first and second load terminals and a control gate terminal; means connecting the load terminals of said first switch means in series with said load between said first and second line terminals of said source; a series resistance capacitance network connecting the gate terminal of said first switch means to said first load terminal of said second switch means, means connecting said second load terminal of said second switch means to said neutral terminal of said source; neutral referenced control circuit means for developing a series of output trigger pulses synchronized with the zero crossover voltage point of said source; and means applying the output of the control circuit means to the gate terminal of said second switch means.
Claim 3
Dependent Claim
194 words
A circuit for controlling the supply of an alternating current voltage source to an electric oven, said circuit comprising: an oven heating element, a first triac connected in series with said heating element and having a reference terminal connected to a first line terminal of said source and its other load terminal connected with said heating element, means connecting the other side of said heating element to the second line terminal of said source; a second triac and an RC circuit connected in series between the gate terminal of said first triac and the neutral terminal of said source; control circuit means including a zero crossover detector connected between one-line terminal of said source and the neutral terminal of said source for providing a series of pulses synchronized with a zero crossover voltage point of said source, means for setting a desired temperature in said oven, means for sensing the temperature of said oven, and means responsive to the output of said zero crossover detector for triggering said second triac a predetermined time interval subsequent to the zero crossover point of said source whenever the temperature of said oven is below the set temperature.
Claim 4
Dependent Claim
194 words
A circuit for controlling the supply of an alternating current voltage source to an electric oven, said circuit comprising: an oven heating element, a first triac connected in series with said heating element and having a reference terminal connected to a first line terminal of said source and its other load terminal connected with said heating element, means connecting the other side of said heating element to the second line terminal of said source; a second triac and an RC circuit connected in series between the gate terminal of said first triac and the neutral terminal of said source; control circuit means including a zero crossover detector connected between one-line terminal of said source and the neutral terminal of said source for providing a series of pulses synchronized with a zero crossover voltage point of said source, means for setting a desired temperature in said oven, means for sensing the temperature of said oven, and means responsive to the output of said zero crossover detector for triggering said second triac a predetermined time interval subsequent to the zero crossover point of said source whenever the temperature of said oven is below the set temperature.
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) | 1976-11-26 | 1977-05-28 | 1977-11-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-11-26 | 1981-05-28 | 1981-11-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-11-26 | 1985-05-28 | 1985-11-27 | $7700.00 | Window Closed / Lapsed |