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US 4,375,609 AGranted
Analog/digital drive speed control circuit
AssigneeAbex Corporation
InventorRobert F. Wolf
Life of this patent
Estimating the term…
Abstract
A speed control circuit has a comparator which compares a voltage signal which is indicative of the actual speed of a shaft with a digital reference which is indicative of the desired speed of the shaft. If the actual speed is different than the desired shaft speed, a bi-directional control mechanism is operated in one direction or the other to adjust the actual speed of the shaft. The operation of the bi-directional control mechanism is periodically interrupted to increment the amount the actual shaft speed is changed to prevent overshoot of the desired speed.
Claims10
A speed control circuit comprising a device having a rotatable shaft,
- means for generating a voltage signal which is proportional to the rotational speed of the shaft,
- a digital voltmeter having a binary coded decimal output,
- means for supplying the voltage signal to the digital voltmeter,
- a digital comparator having a greater than output signal and a less than output signal,
- means for supplying the output of the digital voltmeter to the digital comparator,
- means for generating a reference which indicates a desired shaft speed,
- means for supplying the reference to the digital comparator,
- a bi-directional control mechanism for changing the speed of the shaft,
- first means for operating the bi-directional control mechanism in one direction to cause the speed of the shaft to increase,
- second means for operating the bi-directional control mechanism in the other direction to cause the speed of the shaft to decrease,
- first means for connecting the comparator greater than output signal to the second operating means,
- second means for connecting the comparator less than output signal to the first operating means,
- wherein the comparator examines the voltage signal with respect to the reference and the greater than output signal is actuated to cause the second operating means to decrease the speed of the shaft when the voltage signal indicates the shaft speed is greater than the desired speed and the less than output signal is actuated to cause the first operating means to increase the speed of the shaft when the voltage signal indicates the shaft speed is less than the desired speed, and
- means for disabling the first and second operating means to thereby limit the time of operation of the first and second operating means.
11 more elements
Dependencies are inferred from the claim text.