| 摘要 |
PURPOSE:To prevent a breakage of a tap by a method wherein a difference in numbers of revolutions between driving and driven portions is compared with a predetermined preset value and an abnormal alarm signal is output. CONSTITUTION:When a difference in numbers of revolutions between driving portion 13 and a driven portion 16 is not exceeding a peset value in a differentiator 27, a comparator 29 will not output and an alarm circuit 30 will not be operated. On the other hand, when a tap 18 is overloaded and the revolution thereof is reduced, an output of the differentiator 27 is compared in the comparator 29, an output of the comparator 29 is input into the alarm circuit 30 and an abnormal alarm signal is output. The alarm circuit 30 is preset in a readily operatable condition by a trigger circuit 31. |
