DRIVE SPEED CONTROLLER FOR MOTOR

摘要

PURPOSE:To improve control response by providing a sub-rotor having a smaller diameter than that of a rotor and provided with a reflector, then detecting rotation of the sub-rotor through a rotation detector comprising a LED and a phototransistor and carrying out servo control based on an detected output. CONSTITUTION:Rotary torque of a motor 6 is transmitted from a rotor 1 through a belt 12 to a sub-rotor 11 and the rotary torque produced in the sub- rotor 11 is transmitted through a belt 2 to a flywheel 8 thus rotating a capstan arranged coaxially and feeding a tape. At this time, light emitted from a LED 4b is projected to a reflector 3 and the reflected light is picked up by a phototransistor 4a thus detecting the rotation of the sub-rotor 11. When the output is fed back to a servo circuit 5, rotary speed of the sub-rotor 11 is maintained constant and thereby the rotary speed of the motor is maintained constant.