| 摘要 |
PURPOSE:To enable detecting an abnormality in speed exactly by outputting a speed abnormality signal, when the difference between the speed signal of a motor and a reference speed signal is more than a given value. CONSTITUTION:When a reference speed signal is applied to a terminal 21, a motor 25 rotates via F/V circuit 22, adder 23 and motor driving circuit 24. Also, a phase comparator 27 applies to the adder 23 a voltage corresponding to the phase difference between a frequency signal outputted from an encoder 26 and a reference speed signal frequency. On the other hand, when the speed of said motor 25 deviates from a reference speed and from tolerance limits, a speed abnormality detection signal is outputted from a comparator 30. In this manner, it is possible to perform an exact abnormality detection. |
