Patent US3754177A successfully refreshed from Google Patents.
US3754177A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Solid state controller
Assignee: LECTRON CORP
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Filing: 1972-09-05
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Granted: 1973-08-21
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Expires: 1992-09-05
Abstract
Abstract A solid state circuit for slow turn on and turn off of power to a load to limit surges and transients normally associated with the switching of large loads. A thyristor and a switching unit for turning the thyristor on and off, with a phase shift network in the switching unit for turn on time control. A radiation sensitive resistor in the phase shift network illuminated by a source in turn energized by a porportional control circuit having a time delay for build-up and decay of illumination. A two-step delay circuit, and a circuit suitable for single phase and three phase systems.
Inventors
- 👤 Reilly R O
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 13:05
CPC Classifications
H; H02; H02H; H02H9/00; H02H9/001; H02M; H02M1/00; H02M1/08; H02M1/084; H02M1/088; H02M1/092; H02M5/00; H02M5/02; H02M5/04; H02M5/22; H02M5/25; H02M5/257; H02M5/2573; H02P; H02P1/00; H02P1/16; H02P1/26; H02P1/28
Claims Analysis
Total Claims: 13
Claim 1
Independent Claim
162 words
In a circuit for controlling buildup of power to a load, the combination of: a thyristor for connection in circuit between line and load, said thyristor having a control element; a switching unit connected to said control element for turning said thyristor on and including a phase shift network for varying the time of thyristor turn on, said network including a first resistor having a resistance varying as a function of received radiation; a first radiation source connected in circuit with a first current control unit, with radiation from said first source directed to said first resistor; a first RC delay circuit for said first current control unit for increasing current through said current control unit to said first radiation source; a voltage source; and means for connecting said voltage source across said first delay circuit for charging the capacitance thereof, with the current to said first radiation source increasing as said capacitance charges to increase the on time of said thyristor.
Claim 2
Dependent Claim
162 words
In a circuit for controlling buildup of power to a load, the combination of: a thyristor for connection in circuit between line and load, said thyristor having a control element; a switching unit connected to said control element for turning said thyristor on and including a phase shift network for varying the time of thyristor turn on, said network including a first resistor having a resistance varying as a function of received radiation; a first radiation source connected in circuit with a first current control unit, with radiation from said first source directed to said first resistor; a first RC delay circuit for said first current control unit for increasing current through said current control unit to said first radiation source; a voltage source; and means for connecting said voltage source across said first delay circuit for charging the capacitance thereof, with the current to said first radiation source increasing as said capacitance charges to increase the on time of said thyristor.
Claim 3
Dependent Claim
44 words
A circuit as defined in claim 1 wherein said current control unit includes a transistor with emitter and collector in series with said first radiation source, with said first delay circuit connected to the transistor base for controlling current in said first radiation source.
Claim 4
Dependent Claim
13 words
A circuit as defined in claim 1 whereiN said thyristor is a triac.
Claim 5
Dependent Claim
17 words
A circuit as defined in claim 1 wherein said controlled rectifier comprises two thyristors connected in parallel.
Claim 6
Dependent Claim
43 words
A circuit as defined in claim 1 for operation with a three phase system and including three of said thyristors and switching units, with radiation from said first radiation source directed to the first resistors of each of the three switching unit networks.
Claim 7
Dependent Claim
49 words
A circuit as defined in claim 5 including a closed container, with the first resistors of each of the three phase shift networks mounted in the walls of said container, and with said first radiation source mounted within said container spaced substantially equally from each of the first resistors.
Claim 8
Dependent Claim
28 words
A circuit as defined in claim 6 wherein said container has a square cross section with four faces, with said first resistors mounted in three of said faces.
Claim 9
Dependent Claim
111 words
A circuit as defined in claim 1 including: a second resistor in said phase shift network and having a resistance varying as a function of received radiation; a second radiation source connected in circuit with a second current control unit, with radiation from said second source directed to said second resistor; a second RC delay circuit for said second current control unit for increasing current through said unit to said second radiation source; and means for connecting said voltage source across said second delay circuit for charging the capacitance thereof, with the current to said second radiation source increasing as said capacitance charges to increase the on time of said thyristor.
Claim 10
Dependent Claim
26 words
A circuit as defined in claim 8 with said phase shift network connected across said thyristor and with said first and second resistors connected in parallel.
Claim 11
Dependent Claim
20 words
A circuit as defined in claim 8 including means connecting said second current control unit to said first delay circuit.
Claim 12
Dependent Claim
52 words
A circuit as defined in claim 10 wherein said second current control unit and radiation source and said second phase shift network including said second resistor are selected such that fully charging the capacitance of said second delay circuit turns said thyristor on only for a portion of the available on time.
Claim 13
Dependent Claim
54 words
A circuit as defined in claim 8 wherein said second current control unit and radiation source and said second phase shift network including said second resistor are selected such that fully charging the capacitance of said second delay circuit turns said thyristor on at a predetermined and adjustable phase angle of each half cycle.
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) | 1976-08-20 | 1977-02-19 | 1977-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-08-20 | 1981-02-19 | 1981-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-08-20 | 1985-02-19 | 1985-08-21 | $7700.00 | Window Closed / Lapsed |