Douglas E Webster

US Patent:

43743528, Feb 15, 1983

Filed:

Jul 21, 1981

Appl. No.:

6/285588

Inventors:

Douglas G. Webster - Saratoga CA

Assignee:

Veeco/Macronetics Inc. - Sunnyvale CA

International Classification:

H02P 324

US Classification:

318762

Abstract:

A three-terminal network which electrically senses the time at which the voltage applied to an AC induction motor is removed and concurrently therewith utilizes energy which was previously stored in a capacitor to effect eddy-current braking of the AC induction motor is disclosed. The disclosed system may be utilized to quickly, i. e. , within two revolutions, brake a two-terminal shaded-pole induction motor, or a two-terminal unidirectional split-phase motor, or a three-terminal bidirectional split-phase motor.

US Patent:

44490828, May 15, 1984

Filed:

Dec 17, 1981

Appl. No.:

6/331873

Inventors:

Douglas G. Webster - Saratoga CA

International Classification:

G05B 500

US Classification:

318326

Abstract:

In a system for controlling within a very tight tolerance the speed of a DC motor, a first servo loop servos the motor to a speed which is close to ideal but not perfect. A second servo loop, operating in concert with the first servo loop, acts as a vernier or fine tuning adjustment to add any necessary correction needed to bring the motor into substantially perfect positional alignment. The first servo loop utilizes ramp and velocity feedback techniques to achieve constant acceleration by tracking or following a speed command signal profiled to have a linear velocity ramp portion and a final constant velocity portion where acceleration terminates and speed remains constant. Once the motor has accelerated up to the desired speed the second servo loop begins to function in concert with the first servo loop. The second servo loop utilizes "phase-lock" techniques wherein a phase error signal is derived by comparing the phase of a reference signal generated from a crystal oscillator with the phase of a digital tachometer signal obtained from the motor.

US Patent:

40741966, Feb 14, 1978

Filed:

Aug 2, 1976

Appl. No.:

5/710566

Inventors:

Douglas G. Webster - Saratoga CA

International Classification:

G01P 348

US Classification:

324166

Abstract:

A speedometer-odometer apparatus is described comprising an encoding apparatus for generating pulses as a function of the distance a vehicle is moved, a calibrating apparatus and an indicating circuit means for visually indicating the distance and speed of the movement. Coupled between the encoding apparatus and the indicating circuit means, the calibrating apparatus is provided for controlling the number of pulses delivered to the indicating circuit means from the encoding apparatus so that the indicating circuit means will provide a predetermined output when the vehicle in which the apparatus is mounted is moved a predetermined distance. For providing a highly accurate and direct readout of the distance, there is provided, in the indicating circuit means and coupled to the output of the calibrating apparatus, a plurality of division circuits. The division circuits are provided for dividing the output of the calibrating means so as to provide a direct readout of the distance the vehicle moves to an accuracy of at least one part in ten thousand. For providing an indication of the speed of the vehicle there is also provided, coupled to the output of the calibrating means, a time base generator, a second plurality of division circuits and latches.