| 摘要 |
PURPOSE:To obtain a positive braking operation without reverse rotation of a DC motor substantially by automatically completing the braking operation after the rotating speed is decelerated by the reverse braking to a predetermined speed even if load inertia is varied. CONSTITUTION:When negative voltage is applied to a terminal 9, a transsitor 2, and transistors 12, 15 in a normal-reverse control circuit 8 are conducted to cause the motor 16 to be normally rotated. When the voltage at the terminal 9 is altered to positive voltage, the transistor 2 is turned off, and the supply voltage path is interrupted, but simultaneously positive differentiated pulse is operated through a differentiating circuit 10a temporarily to turn on the transistor 3 through an inverter circuit 10. Thus, the transistors 13, 14 are conducted due to the positive voltage input of the terminal 8a, and the motor 16 is reversely braked. Since the potential at C is lower than the potential at B at this time, the transistors 4, 3 remain on. When the motor is decelerated to a value lower than a predetermined rotating speed, the potential at B is raised to cause the transistors 4, 3 to be turned off. Thus, the motor 16 is automatically interrupted. |
