| 摘要 |
PURPOSE:To detect the abnormal revolution (uncontrolled revolution) of a motor by simple constitution by using two re-triggerable monomultivibrators. CONSTITUTION:When a revolution detecting signal (a) is interrupted and a motor 1 is turned uncontrolledly, a monostable multivibrator 3 is not triggered, and an output (b) is brought to a LOW level. A monostable multivibrator 4 is not also triggered by the output (b), and an output (c) is brought to the LOW level. That is, the output (c) is acquired as the LOW level to the HIGH level at the normal time under an abnormal state at that time. When a speed control circuit 2 loses a control function and the motor 1 is rotated uncontrolledly, the period of the revolution detecting signal (a) is made smaller than 260musec, and the monostable multivibrator 3 is re-triggered and the output (b) is brought to the HIGH level. The monostable multivibrator 4 is not triggered by the output (b), and the output (c) is brought to the LOW level. That is, the output (c) at that time is also obtained as the LOW level reverse to the normal time. |
