PURPOSE: To suppress a torque ripple to the minimum limit and to particularly improve a wow and flutter for starting a tape by reducing the maximum voltage applied at the time of driving it with a constant current lower than a voltage applied at the time of driving it with a constant voltage.
CONSTITUTION: When a reel is rotated in a range of available rotating speed, transistors Q1, Q6 hold OFF, and a constant current is supplied by a circuit having an amplifier A2, and transistors Q2, Q3, Q4, Q5 to a reel motor 14. Since a transistor Q7 is turned ON, Zener diodes Dz, Dz' (Dz'<Dz) are connected in parallel. Thus, the maximum value of the voltage applied to the motor 14 is determined by the diode Dz'. When the reel is decelerated from the available speed, the transistor Q1 is turned ON after the amplifier A1 is latched. Accordingly, the transistor Q7 is turned OFF, and a constant voltage is applied to the motor 14 by the diode Dz.
HITOMI TADASHI
TSUKIHASHI AKIRA
HAYASHI ATSUO
SANYO ELECTRIC CO