POSITIONERINGSDRIVANORDNING

摘要

The drive shaft of a motor can be coupled to an output shaft by an electromagnetically activated friction clutch. The output shaft can be braked by an electromagnetically activated friction brake. The motor drive shaft rotates at constant speed. The rotary speed of the output shaft is regulated by negative-feedback action to maintain a selected value, by activating the clutch and brake alternately as necessary. The activating signals for the clutch and brake are pulse-width-modulated activating signals. The output shaft can be stopped in at least one predetermined angular position when commanded to do so. The movable parts of the brake and clutch are of minimal mass, and the speed-regulating system includes a speed feedback transducer system of very high resolution.