| 摘要 |
PURPOSE:To prevent a motor from becoming an overrotation by flowing a current to generate a torque of reverse direction in a motor when the speed of the motor becomes higher than the set value. CONSTITUTION:A speed detection pulse signal F from a speed detector 28 is applied to an input terminal 10, and monostable multivibrators 14, 16 output pulse signals MM2, MM3 of pulse widths T2, T3 synchronized with the pulse signal F. When the period T0 of the signal F is larger than the set value T1, the output Q of a flip-flop 12 becomes ''L'', and the output Q' becomes ''H'', and the signals MM3 and a rotation command signal to be applied to a terminal 29 are input to a controller 22 as they are. If becoming T0<T1, the output of the flip-flop 12 is inverted, and the signal MM2 and the rotation command signal are inverted and inputted to the controller 2. |
