Speed control system for DC motor - involves motor acting briefly as generator to obtain actual speed signal for difference control signal generation

摘要

The speed control system for a direct current motor, has its running time broken up into a sequence of alternate working and measuring intervals. During the measuring interval the motor acts as a generator whose output is used to generate a difference control signal for adjusting the speed. The ratio between the working and measuring intervals is fixed. The motor is in series with a switch controlled by a clock such that it alternates between working and measuring steps. The difference signal controls a pulse modulator for the motor power supply.