Contactless switch for motor driven rheostats and transformers - has photoelectric chopper discs and bistable circuits

摘要

The contractless switch for motor-driven rheostats and variable transformers comprises a DC motor coupled via gearing and clutch to a shaft driving the rheostat. Mounted on the shaft are three chopper discs with adjustable apertures. Associated with each disc are pairs of light-emitting diodes and photo-detectors, the first disc having a double arrangement. The outputs from the photo-detectors are taken to bistable circuits. The bistables operate relays whose contacts control the motor reversal and stopping operations. Control of motor speed is via setting potentiometers and current limiting amplifiers connected in the supply to the motor.