US3864612A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Firing angle retardation control
Assignee: Individual
•
Filing: 1973-03-09
•
Granted: 1975-02-04
•
Expires: 1993-03-09
Abstract
Abstract In a full wave rectified control circuit for a D-C motor comprising two banks of silicon controlled rectifiers for forward and reverse operation, there is provided a pulse generating system which is responsive to an error signal and which applies a firing pulse to each of the control SCR''s at varying times during the input cycle in order to vary the power input to the motor. The pulse generating system provides for overlap in the conduction periods of the forward and reverse banks of SCR''s and provides each bank with a firing angle of up to 240* of the input waveform.
Inventors
- 👤 James Sidney Whited
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 23:28
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/292; H02P7/293
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
127 words
A control system for a D-C motor as described in claim 1 wherein the control circuit and rectifying network comprises: A. an isolating power transformer connected to the power supply having first and second output terminals and a center tap, the center tap being connected directly to one side of the motor; B. said first bank of forward conducting SCR''s including first and second forward current passing SCR''s connected to the first and second transformer terminal respectively and to the other side of the motor through a smoothing inductance; and C. said second bank of reverse conducting SCR''s including first and second reverse current passing SCR''s connected to the first and second transformer terminals respectively, and to the other side of the motor through a smoothing inductance.
Claim 2
Dependent Claim
14 words
a second transistor which is turned off by the conduction of the first transistor,
Claim 3
Dependent Claim
15 words
a first capacitor which is short circuited to ground by conduction of the second transistor,
Claim 4
Dependent Claim
52 words
A control system for a D-C motor as described in claim 2 wherein the pulse generator system is comprised of two substantially identical channels, one providing firing pulses for the first and second forward current passing SCR''s and the other providing firing pulses for the first and second reverse current passing SCR''s.
Claim 5
Dependent Claim
40 words
A control system for a D-C motor as described in claim 3 wherein there is provided a separate timing means for each channel, providing each pulse generator channel with an operating range of greater than 180* of the input waveform.
Claim 6
Dependent Claim
10 words
a constant current source connected to charge the first capacitor,
Claim 7
Dependent Claim
11 words
a second capacitor which is charged by the error signal means,
Claim 8
Dependent Claim
34 words
A control system for a D-C motor as described in claim 1 wherein the timing means comprises a capacitor network which effectively stretches the positive portion of the input waveform to greater than 180*.
Claim 9
Dependent Claim
96 words
A control system for a D-C motor operable from an alternating current input power supply comprising: A. a control circuit connected to the power supply and to the motor to provide rectified power to the motor; B. a gated rectifying network in the control circuit which is rendered conductive by firing pulses; C. a pulse generating system which provides firing pulses to the gated rectifying network; D. means to supply to the pulse generator system an error signal which represents the difference between actual motor speed and desired motor speed; E. said pulse generating system including:
Claim 10
Dependent Claim
45 words
a programmable unijunction transistor having its anode connected to the first capacitor and having its gate connected to said second capacitor such that it will fire when said first capacitor is charged to a value more positive than the charge on said second capacitor, and
Claim 11
Dependent Claim
68 words
a pulsing circuit which transmits firing pulses to the gated rectifying network when the programmable unijunction transistor is fired; and F. means for developing a timing signal referenced to the alternating current input signal, said timing signal means coupled to the pulse generating system to provide for the generation of firing pulses over an operating range unrestricted by the zero crossover point of the alternating current input signal.
References Cited (Backward Citations)
US3624837A
Cited
US3731172A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1978-02-03 | 1978-08-05 | 1979-02-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-03 | 1982-08-05 | 1983-02-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-03 | 1986-08-05 | 1987-02-04 | $7700.00 | Window Closed / Lapsed |