US3573583A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Dc motor speed control system
Assignee: National Aeronautics and Space Administration
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Filing: 1969-12-16
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Granted: 1971-04-06
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Expires: 1989-12-16
Abstract
Abstract A motor speed control circuit wherein a signal proportional to the IR drop of the armature is utilized to drive a self-excited inverter to obtain a feedback voltage equal to the IR drop of the armature. The feedback voltage is added as a positive feedback to a constant DC voltage to form the input to a unity gain amplifier. The last stage of the amplifier is in series with the armature of the motor. The speed at which the motor operates is controllable by means of varying the value of the constant DC voltage.
Inventors
- 👤 William M Mccampbell
- 👤 Hershel M Nance
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-26 19:15
CPC Classifications
H; H02; H02P; H02P7/00; H02P7/06; H02P7/18; H02P7/24; H02P7/28; H02P7/285; H02P7/29; H02P7/291; Y; Y10; Y10S; Y10S388/00; Y10S388/90; Y10S388/902
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
125 words
A motor control system comprising: an electric motor; a unity voltage gain amplifier connected to said motor for controlling the voltage applied to the armature of said motor; first control means to apply a selectively variable DC voltage to the input of said amplifier to selectively vary the voltage applied to said armature; a variable resistor connected in series with said armature circuit; a self-excited inverter having an input connected across said resistor for converting the DC voltage drop across said resistor to an AC voltage of increased magnitude; rectifier means connected to the output of said inverter for converting said AC output to a DC voltage; and means for applying said DC voltage to the input of said amplifier as a positive feedback voltage.
Claim 2
Dependent Claim
125 words
A motor control system comprising: an electric motor; a unity voltage gain amplifier connected to said motor for controlling the voltage applied to the armature of said motor; first control means to apply a selectively variable DC voltage to the input of said amplifier to selectively vary the voltage applied to said armature; a variable resistor connected in series with said armature circuit; a self-excited inverter having an input connected across said resistor for converting the DC voltage drop across said resistor to an AC voltage of increased magnitude; rectifier means connected to the output of said inverter for converting said AC output to a DC voltage; and means for applying said DC voltage to the input of said amplifier as a positive feedback voltage.
Claim 3
Dependent Claim
15 words
The apparatus of claim 1 wherein said amplifier comprises a 2-stage transistor emitter follower amplifier.
Claim 4
Dependent Claim
24 words
The apparatus of claim 1 wherein said selectively variable DC voltage applied to the input of said amplifier is variable over a continuous range.
Claim 5
Dependent Claim
49 words
The apparatus of claim 1 wherein: said first control means includes a source of DC voltage; a resistor and Zener diode connected in series across said DC source; a potentiometer connected across said Zener diode; and said potentiometer having a movable tap coupled to the input of said amplifier.
Claim 6
Dependent Claim
20 words
The apparatus of claim 1 wherein said variable resistor has a resistance substantially smaller than the resistance of said armature.
Claim 7
Dependent Claim
46 words
The apparatus of claim 4 wherein said movable tap is connected to one side of a coupling resistor, the other side of said resistor being connected to the input of said amplifier and wherein the output of said rectifier means is connected across said coupling resistor.
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) | 1974-04-05 | 1974-10-05 | 1975-04-06 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-05 | 1978-10-05 | 1979-04-06 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-05 | 1982-10-05 | 1983-04-06 | $7700.00 | Window Closed / Lapsed |