The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jun. 12, 1990
Filed:
Jun. 23, 1988
Harold V Clark, Los Altos, CA (US);
Ampex Corporation, Redwood City, CA (US);
Abstract
A system for controlling a pulse-driven dc motor includes a pulsed grounding switch, an inductor connected between the pulsed grounding switch and the armature of the dc motor, and a tracking circuit connected across the inductor. The control system further includes a variable resistor that provides a series path through the inductor for dissipating generated armature current from the motor. In operation, the resistance provided by the variable resistor depends upon the counter emf generated by the motor and upon transient voltages induced across the inductor when the pulsed grounding switch is periodically opened and closed. More particularly, the variable resistor provides minimal resistance when the back emf of the motor is low and provides increasing resistance as the back emf of the motor increases.