| 摘要 |
<p>PURPOSE:To realize improvement of safety in operation through emergency stop of machine operation by disconnection of electromagnetic clutch and effectuation of electromagnetic brake if power failure occurs by controlling over- excitation, normal excitation and reverse excitation of a pair of coils of electromagnetic clutch and brake. CONSTITUTION:A multivibrator 58 outputs a set signal of positive voltage when a pulse is input thereto but outputs a reset signal of level zero because it is reset to zero when a pulse is not input for the predetermined time d. Therefore, when the commercial power supply fails, a retriggerable one-shot multivibrator 58 outputs a power failure detection signal of level zero to a brake preference circuit 18a. A transistor control circuit 18 thus separates the electromagnetic clutch by reversely exciting a coil 20 of the electromagnetic clutch and simultaneously effectuates the electromagnetic brake by over-excitation of coil 32 of the electromagnetic brake. Thereby, operation of machine is urgently suspended in order to prevent a trouble of machine due to the power failure. 56:.</p> |
