| 摘要 |
PURPOSE:To reduce braking load to a motor by applying a short brake with a short brake means and changing over the direction of rotation of the motor. CONSTITUTION:An adding circuit 6 adds a phase comparison signal PC and a speed control signal FV. A comparator 7 converts an output from the adding circuit 6 into a PWM control signal on a threshold level control signal. A drive signal FW/RV is brought to L when a motor 20 is forward rotated, and to H when the motor 20 is reversely rotated. Since sudden braking load is applied to the motor 20 when the direction of rotation is changed over instantaneously, a short brake is applied by bringing a short brake signal SBK to L and short- circuiting transistors 13 and 14. The direction of rotation is changed over. |
