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:
Apr. 08, 1997
Filed:
Feb. 09, 1995
Ramin Younessi, Tigard, OR (US);
Brian Houghton, Fort Collins, CO (US);
Woodward Governor Company, Fort Collins, CO (US);
Abstract
A limited angle torque motor and control circuit are adapted to convert an electrical demand signal of varying magnitude into a motor shaft position relating to the magnitude of the demand signal. More particularly, a bidirectional motor is provided having two stator coils wound in phase opposition, so that the torques produced by the currents in the opposedly wound coils are summed such that the coil having the greater current controls the direction of rotor rotation. A position sensor provides feedback of the present shaft position; the magnitude of the feedback signal being indicative of motor shaft position. Finally, an electronic control circuit which is responsive to both the demand signal and the shaft position signal is provided and has two outputs for simultaneously driving the current in each respective stator coil. A summing means is included in the control circuit for combining the shaft position signal and demand signal so as to produce an error signal. The error signal, in turn, is input to a modulator that creates a differential between the two control circuit outputs to drive the two stator coil currents, thereby causing the motor shaft to rotate toward the desired shaft position.