US3648151A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Chopper circuit
Assignee: Sevcon Engineering Ltd
•
Filing: 1969-08-07
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Granted: 1972-03-07
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Expires: 1989-08-07
Abstract
Abstract A variable mark-space ratio pulse controller in which a main thyristor for controlling the supply of direct current to a load is commutated by discharge of a capacitor occuring immediately on reversal of the charge thereon so that the use of a separate thyristor which is turned on to pass discharge current from the commutating capacitor to commutate the main thyristor is avoided.
Inventors
- 👤 David Gurwicz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 22:22
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; Y; Y10; Y10S; Y10S388/00; Y10S388/907; Y10S388/917; Y10S388/919
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
159 words
A variable mark-space ratio pulse controller which comprises a main thyristor for controlling the supply of direct current to a load, a commutating capacitor, an inductor in series with the capacitor, a first path in series with the capacitor and inductor, and a second path disposed in parallel with the first path, wherein the first and second paths are provided by a triac device, the gate of which is connected in said first path to provide uncontrolled unidirectional conduction of current through the gate and semiconductor layers of the triac in a direction opposed to the direction of current flow through the main thyristor, the gate of the triac device further being connected to a supply of triggering pulses which renders the triac conductive in the same direction as that of current flow through the main thyristor, the triac thereby functioning both as a diode in one current direction and as a controlled rectifier in the other current direction.
Claim 2
Dependent Claim
159 words
A variable mark-space ratio pulse controller which comprises a main thyristor for controlling the supply of direct current to a load, a commutating capacitor, an inductor in series with the capacitor, a first path in series with the capacitor and inductor, and a second path disposed in parallel with the first path, wherein the first and second paths are provided by a triac device, the gate of which is connected in said first path to provide uncontrolled unidirectional conduction of current through the gate and semiconductor layers of the triac in a direction opposed to the direction of current flow through the main thyristor, the gate of the triac device further being connected to a supply of triggering pulses which renders the triac conductive in the same direction as that of current flow through the main thyristor, the triac thereby functioning both as a diode in one current direction and as a controlled rectifier in the other current direction.
Claim 3
Dependent Claim
29 words
A controller as claimed in claim 1 disposed in series with a load comprising one of a DC series motor and the field windings of a DC shunt motor.
References Cited (Backward Citations)
US3242352A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-03-07 | 1975-09-06 | 1976-03-07 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-03-07 | 1979-09-06 | 1980-03-07 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-03-07 | 1983-09-06 | 1984-03-07 | $7700.00 | Window Closed / Lapsed |