Patent US3777235A successfully refreshed from Google Patents.
US3777235A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Variable dc motor power source
Assignee: Power Systems Inc
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Filing: 1971-07-19
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Granted: 1973-12-04
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Expires: 1991-07-19
Abstract
Abstract Precise control of fractional horse power DC motors is provided by a DC power source having a negative feedback amplifier, the signal at the output of the amplifier being controlled by a voltage derived from a potentiometer. A pulsed voltage having a peak amplitude somewhat less than the dead band voltage threshold of the amplifier is applied to an input terminal of the amplifier for low speed control of the motor. Peak current limiting with a load compensator operates to reduce the output voltage of the power source after a short circuit is removed.
Inventors
- 👤 A Lahti
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-27 20:36
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/288; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/902; Y10S388/903; Y10S388/907; Y10S388/91; Y10S388/916
Claims Analysis
Total Claims: 16
Claim 1
Independent Claim
409 words
A variable power source for controlling a D. C. motor said source comprising: a. first means for generating a control voltage variable between a minimum level and a maximum level; b. second means for generating a series of constant amplitude pulses; c. third means operatively connected to said first and second means for summing said control voltage and said constant amplitude pulses, said constant amplitude pulses being superimposed on said control voltage and defining a combined signal, said combined signal at a first value when said control voltage is at its minimum level, said combined signal at a second value when said control voltage is at an intermediate level, said combined signal at a third level when said control voltage is at its maximum level; and d. driver means having input and output terminal means, said input terminal means operatively connected to said third means, said combined signal applied to said input terminal means, said output terminal means adapted for interconnection with said D. C. motor, said driver means having non-conducting and conducting states, said driver means in said non-conducting state when said combined signal applied to said input terminal means is at said first value, said driver means in said conducting state and a pulsed drive signal presented at said output terminal means for controlling said D. C. motor when said combined signal applied to said input terminal means is at said second value, said driver means in said conducting state and a continuous drive signal presented at said output terminal means for controlling said D.C. motor when said combined signal applied to said input terminal means is at said third value, said driver means including e. threshold means operatively connected to said third means for establishing a threshold level, the amplitude of said pulses being at a level which is smaller than said threshold level; and f. amplifier means havIng input and output terminal means, said amplifier means input terminal means operatively connected to said threshold means, said combined signal applied to said amplifier means input terminal means via said threshold means, said amplifier means output terminal means adapted for interconnection with said D. C. motor, said pulsed signal presented at said amplifier means output terminal means when said combined signal applied to said threshold means is at said second value, said continuous drive signal presented at said amplifier means output terminal means when said combined signal applied to said threshold means is at said third value.
Claim 2
Dependent Claim
409 words
A variable power source for controlling a D. C. motor said source comprising: a. first means for generating a control voltage variable between a minimum level and a maximum level; b. second means for generating a series of constant amplitude pulses; c. third means operatively connected to said first and second means for summing said control voltage and said constant amplitude pulses, said constant amplitude pulses being superimposed on said control voltage and defining a combined signal, said combined signal at a first value when said control voltage is at its minimum level, said combined signal at a second value when said control voltage is at an intermediate level, said combined signal at a third level when said control voltage is at its maximum level; and d. driver means having input and output terminal means, said input terminal means operatively connected to said third means, said combined signal applied to said input terminal means, said output terminal means adapted for interconnection with said D. C. motor, said driver means having non-conducting and conducting states, said driver means in said non-conducting state when said combined signal applied to said input terminal means is at said first value, said driver means in said conducting state and a pulsed drive signal presented at said output terminal means for controlling said D. C. motor when said combined signal applied to said input terminal means is at said second value, said driver means in said conducting state and a continuous drive signal presented at said output terminal means for controlling said D.C. motor when said combined signal applied to said input terminal means is at said third value, said driver means including e. threshold means operatively connected to said third means for establishing a threshold level, the amplitude of said pulses being at a level which is smaller than said threshold level; and f. amplifier means havIng input and output terminal means, said amplifier means input terminal means operatively connected to said threshold means, said combined signal applied to said amplifier means input terminal means via said threshold means, said amplifier means output terminal means adapted for interconnection with said D. C. motor, said pulsed signal presented at said amplifier means output terminal means when said combined signal applied to said threshold means is at said second value, said continuous drive signal presented at said amplifier means output terminal means when said combined signal applied to said threshold means is at said third value.
Claim 3
Dependent Claim
312 words
A variable power source for generating a drive signal for controlling a DC motor, said source comprising: a. rectifying means; b. control means operatively connected to said rectifying means for generating a variable control voltage variable between a minimum level and a maximum level; c. generator means operatively connected to said rectifying means for generating a series of fixed amplitude pulses; d. summing means operatively connected to said control means and said generating means for summing said control voltage and pulses, said pulses being superimposed on said control voltage and defining a combined signal, said combined signal at a first value when said control voltage is at its minimum level, said combined signal at a second value when said control voltage is at an intermediate level, said combined signal at a third value when said control voltage is at its maximum level; e. threshold means operatively connected to said summing means, said threshold means establishing a threshold level, said combined signal at said first value being less than said threshold level, said combined signal at said second and third levels being greater than said threshold level; and f. amplifier means having input and output terminal means, said input terminal means operatively connected to said threshold means, said output terminal means adapted for interconnection with the motor, said amplifier means having conducting and non-conducting states, said amplifier means being in the non-conducting state when said combined signal applied to said threshold means is at said first value, said amplifier means being in said conducting state and pulsed driving signals being presented at said output terminal means when said combined signal applied to said threshold means is at said second value, said amplifier means being in said conducting state and continuous drive signals being presented at said output terminal means when said combined signal applied to said threshold means is at said third value.
Claim 4
Dependent Claim
312 words
A variable power source for generating a drive signal for controlling a DC motor, said source comprising: a. rectifying means; b. control means operatively connected to said rectifying means for generating a variable control voltage variable between a minimum level and a maximum level; c. generator means operatively connected to said rectifying means for generating a series of fixed amplitude pulses; d. summing means operatively connected to said control means and said generating means for summing said control voltage and pulses, said pulses being superimposed on said control voltage and defining a combined signal, said combined signal at a first value when said control voltage is at its minimum level, said combined signal at a second value when said control voltage is at an intermediate level, said combined signal at a third value when said control voltage is at its maximum level; e. threshold means operatively connected to said summing means, said threshold means establishing a threshold level, said combined signal at said first value being less than said threshold level, said combined signal at said second and third levels being greater than said threshold level; and f. amplifier means having input and output terminal means, said input terminal means operatively connected to said threshold means, said output terminal means adapted for interconnection with the motor, said amplifier means having conducting and non-conducting states, said amplifier means being in the non-conducting state when said combined signal applied to said threshold means is at said first value, said amplifier means being in said conducting state and pulsed driving signals being presented at said output terminal means when said combined signal applied to said threshold means is at said second value, said amplifier means being in said conducting state and continuous drive signals being presented at said output terminal means when said combined signal applied to said threshold means is at said third value.
Claim 5
Dependent Claim
36 words
The variable power source as claimed in claim 3 including current limiter means operatively connected to said input terminal means for clamping said amplifier means when a short circuit is presented at said output terminal means.
Claim 6
Dependent Claim
58 words
The variable power source claimed in claim 3 wherein said control means includes: a. variable impedance means operatively connected between said rectifying means and said summing means for controlling the level of said control voltage; and b. means operatively connected to said rectifying means and variable impedance means for providing a stable voltage to said variable impedance means.
Claim 7
Dependent Claim
17 words
The variable power source as claimed in claim 4 wherein said variable impedance means is a potentiometer.
Claim 8
Dependent Claim
41 words
The variable DC power source as claimed in claim 3 wherein said generator means includes differentiating means operatively connected between said rectifying means and said summing means, a half wave rectified signal generated by said rectifying means being differentiated into pulses.
Claim 9
Dependent Claim
24 words
The variable DC power sources as claimed in claim 6 wherein said differentiating means is a capacitor, said capacitor being AC coupled to ground.
Claim 10
Dependent Claim
156 words
The variable DC power sources as claimed in claim 3 wherein said amplifier means includes: a. first transistor means havinG base means, collector means, and emitter means, said control voltage having pulses superimposed thereon being applied to said base means of said first transistor; b. second transistor means having base means, collector means, and emitter means, said collector means of said first transistor means connected to said base means of said second transistor means; and c. third transistor means having base means, collector means, and emitter means, said base of said third transistor means connected to said emitter means of said second transistor means; d. said collector means of said first transistor means resistively connected to said rectifier means, said emitter means of said second transistor means resistively connected to said rectifier means, and said emitter means of said third transistor means connected directly to said rectifier means, said amplifier means defining negative feedback amplifier means.
Claim 11
Dependent Claim
287 words
A variable DC power source for generating a signal for controlling a fractional horse power DC motor, said source comprising: a. rectifying means; b. control means operatively connected to said rectifying means for generating a control voltage variable between a minimum level and a maximum level; c. generator means operatively connected to said rectifying means for generating a series of fixed amplitude pulses, said pulses superimposed on said control voltage; d. threshold means for establishing a threshold level, said threshold means operatively connected to said control means, said threshold level being greater than the amplitude of said pulses, said control voltage having said pulses superimposed thereon applied to said threshold means; e. amplifier means operatively connected to said threshold means for generating drive signals, said amplifier means having input and output terminal means, said control voltage having said pulses superimposed thereon being applied to said input terminal means via said threshold means, said drive signals controlling the fractional horse power DC motor, said drive signals presented at said output terminal means when the level of said control voltage havin said pulses superimposed thereon exceeds said threshold level, said drive signals being pulsed signals when said control voltage is at an intermediate level, said drive signals being continuous signals when said control voltage is at its maximum level; f. load compensating means operatively connected to said input terminal means for controlling the amplitude of said drive signals as a function of output current; and g. current limiting means defining positive feedback means operatively connected between said amplifier means output terminal means and said control means, said current limiting means operating to reduce said drive signals at said output terminal means when the load current exceeds a preset level.
Claim 12
Dependent Claim
287 words
A variable DC power source for generating a signal for controlling a fractional horse power DC motor, said source comprising: a. rectifying means; b. control means operatively connected to said rectifying means for generating a control voltage variable between a minimum level and a maximum level; c. generator means operatively connected to said rectifying means for generating a series of fixed amplitude pulses, said pulses superimposed on said control voltage; d. threshold means for establishing a threshold level, said threshold means operatively connected to said control means, said threshold level being greater than the amplitude of said pulses, said control voltage having said pulses superimposed thereon applied to said threshold means; e. amplifier means operatively connected to said threshold means for generating drive signals, said amplifier means having input and output terminal means, said control voltage having said pulses superimposed thereon being applied to said input terminal means via said threshold means, said drive signals controlling the fractional horse power DC motor, said drive signals presented at said output terminal means when the level of said control voltage havin said pulses superimposed thereon exceeds said threshold level, said drive signals being pulsed signals when said control voltage is at an intermediate level, said drive signals being continuous signals when said control voltage is at its maximum level; f. load compensating means operatively connected to said input terminal means for controlling the amplitude of said drive signals as a function of output current; and g. current limiting means defining positive feedback means operatively connected between said amplifier means output terminal means and said control means, said current limiting means operating to reduce said drive signals at said output terminal means when the load current exceeds a preset level.
Claim 13
Dependent Claim
52 words
The variable DC power source as claimed in claim 10 wherein said generator means includes a first capacitor operatively connected to said rectifier means, control means, and amplifier means, said first capacitor operating to differentiate a half wave rectified signal generated by said rectifier means into a series of fixed amplitude pulses.
Claim 14
Dependent Claim
68 words
The variable DC power source as claimed in claim 10 wherein said first capacitor is AC coupled to ground via a second capacitor, said second capacitor operating to ensure that said half wave rectifier AC signal generated by said rectifying means is differentiated and pulses are formed, said pulses being superimposed on said control voltage, said second capacitor having approximately five times the capacitance of said first capacitor.
Claim 15
Dependent Claim
52 words
The variable DC power source as claimed in claim 11, including switch means, said second capacitor resistively connected to ground through said switch means, said second capacitor being discharged through said switch means to ground when said switch means is energized, the discharging of said second capacitor operating as a braking signal.
Claim 16
Dependent Claim
168 words
The variable DC power sources claimed in claim 12 wherein said amplifier means includes: a. first transistor means having base means, collector means, and emitter means, said control voltage having pulses superimposed thereon being applied to said base means of said first transistor; b. a third capacitor serially connected between said base and collector means of said first transistor means for high frequency stabilization of said amplifier means; c. second transistor means having base means, collector means, and emitter means, said collector means of said first transistor means connected to said base means of said second transistor means; and d. third transistor means having base means, collector means, and emitter means, said base means of said third transistor means connected to said emitter means of said second transistor means; e. said collector means of said first and second transistor means resistively connected to said rectifier means, said emitter means of said third transistor means connected directly to said rectifier means, said amplifier means defining negative feedback amplifier means.
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) | 1976-12-03 | 1977-06-04 | 1977-12-04 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-03 | 1981-06-04 | 1981-12-04 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-03 | 1985-06-04 | 1985-12-04 | $7700.00 | Window Closed / Lapsed |