Patent US3723843A successfully refreshed from Google Patents.
US3723843A
Expired / Lapsed
US
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Electrical braking for a d.c. servo motor control circuit
Assignee: Texas Instruments Inc
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Filing: 1971-01-05
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Granted: 1973-03-27
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Expires: 1991-01-05
Abstract
Abstract A circuit is disclosed for controlling operation of a DC shunt field motor that is utilized to drive a variable load, and stop the motor so that the load is accurately positioned at a preselected location. Logic circuitry controls the motor speed to a regulated low speed when the load approaches the desired location. An integrator circuit controls application of dynamic braking to stop the motor when the load is correctly located.
Inventors
- 👤 S Pearson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-04 20:28
CPC Classifications
G; G05; G05D; G05D3/00; G05D3/12; G05D3/14; G05D3/16; G06; G06K; G06K17/00; G06K17/0016
Claims Analysis
Total Claims: 9
Claim 1
Independent Claim
144 words
A d.c. motor control circuit for driving a motor at selectable speeds and stopping the motor at a precise position comprising in combination: a. logic input means for controlling operation of said d.c. motor; b. sources of plus and minus full wave rectified unfiltered drive power; c. circuit means for connecting said drive power to said motor in response to a first logic signal at said input means for driving said motor at maximum speed; d. speed regulator means responsive to a second logic signal at said input means for driving said motor at preselected low speed; and e. integrator means responsive to a third logic signal at said input means for converting motor speed into motor rotation distance, said integrator means controlling the time at which dynamic braking is applied to said d.c. motor to stop motor operation at a precise predetermined position.
Claim 2
Dependent Claim
144 words
A d.c. motor control circuit for driving a motor at selectable speeds and stopping the motor at a precise position comprising in combination: a. logic input means for controlling operation of said d.c. motor; b. sources of plus and minus full wave rectified unfiltered drive power; c. circuit means for connecting said drive power to said motor in response to a first logic signal at said input means for driving said motor at maximum speed; d. speed regulator means responsive to a second logic signal at said input means for driving said motor at preselected low speed; and e. integrator means responsive to a third logic signal at said input means for converting motor speed into motor rotation distance, said integrator means controlling the time at which dynamic braking is applied to said d.c. motor to stop motor operation at a precise predetermined position.
Claim 3
Dependent Claim
86 words
A D.C. motor control circuit as set forth in claim 1 wherein said speed regulator means comprises: a. speed sensing means for providing a first voltage proportional to the actual speed of said motor during low voltage portions of said drive power; and b. detection means for comparing said first voltage with a second voltage proportional to a preselected low speed, said detection means selectively applying power for dynamic braking action as required to regulate the speed of said motor to correspond with said preselected speed.
Claim 4
Dependent Claim
111 words
A d.c. motor control circuit as set forth in claim 2 wherein said speed sensing means comprises a transistor and at least one capacitor connected in series across the armature of said motor, the base of said transistor being electrically connected to one terminal of said armature by resistor means, the emitter of said transistor being connected to the other terminal of said armature and the collector being coupled to said one terminal by capacitor means wherein said transistor is biased into conduction by said resistor means during low voltage portions of said drive power, said capacitor means being operative to store said first voltage proportional to the actual motor speed.
Claim 5
Dependent Claim
69 words
A d.c. motor control circuit as set forth in claim 2 wherein said detection means comprises means for generating said second voltage proporational to said preselected low speed and transistor means for comparing the amplitude of said first and second voltages, said transistor means effecting operation of dynamic braking means when said first voltage is larger and applying drive power to said motor when said second voltage is larger.
Claim 6
Dependent Claim
33 words
A d.c. motor control circuit as set forth in claim 4 wherein said means for generating said second voltage comprises a voltage divider resistor circuit connected across said negative and positive power supplies.
Claim 7
Dependent Claim
45 words
A d.c. motor control circuit as set forth in claim 4 wherein said dynamic braking means comprise a transistor connected directly across the armature of said d.c. motor, said transistor when biased on effectively shunting the armature of said motor to effect dynamic braking thereof.
Claim 8
Dependent Claim
105 words
A d.c. motor control circuit as set forth in claim 1 wherein said integrator means comprises in combination a voltage to current conversion circuit, said circuit converting a voltage proportional to actual motor speed into a current proportional to actual motor speed, and capacitor means for storing said current, the voltage of said capacitor means effectively representing the integral of said current, said capacitor voltage being proportional to distance of rotation of said motor and being operable to provide an enable signal to effect dynamic braking after a predetermined distance of motor rotation to thereby accurately stop said motor rotation at a precise predetermined location.
Claim 9
Dependent Claim
53 words
A motor control circuit as set forth in claim 7 wherein said voltage to current converter comprises a transistor and resistor circuit, a voltage proportional to actual motor speed being applied to the base of said transistor to vary the current flowing through said resistor in proportion to the amplitude of said voltage.
References Cited (Backward Citations)
US3037157A
Cited
US3541418A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1976-03-26 | 1976-09-25 | 1977-03-27 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-03-26 | 1980-09-25 | 1981-03-27 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-03-26 | 1984-09-25 | 1985-03-27 | $7700.00 | Window Closed / Lapsed |