| 摘要 |
PURPOSE:To enable to operate a cage by an inverter even at the abnormal time of the speed signal by generating a speed command signal as a direct frequency instruction signal by a converter when a speed signal becomes abnormal. CONSTITUTION:When a speed signal Vt is normal, a converter 11E is contacted at a terminal b. When the speed signal Vt is abnormal, the converter 11E is contacted at the terminal a, and a frequency command signal Vf becomes the speed command signal Vp. A voltage command signal Vp becomes converted by a function generator 11D from the speed command signal Vp. Even if the speed signal Vt becomes abnormal during feeding of a cage, the speed signal Vt at this time is not necessary and an inverter can be operated. |
