| 摘要 |
PURPOSE:To prevent a power hunting phenomenon and a power backing phenomenon which cause a counterelectromotive force of a hysteresis motor (HM) by controlling an inverter so that the remaining magnetic flux of the HM is demagnetized at the instantaneously stopping time. CONSTITUTION:An input current Ii is detected as a current signal I'1 by an inverter input current detecting CT16-1, rectifier 16-2 and voltage signal converter resistor 16-3. A setter 17 is set to a slight input current signal Igamma by considering the stability and a current to a fan. A comparator 18 applies an output to a switching controller 19 when I'1-Igamma>0. The controller 19 outputs a holding signal to a switching circuit 20 according to the output of a power interruption detector 14, and switches the set inverter output voltage value from a rated voltage setter 9-1 to an instantaneous stopping time voltage setter 21. The set value E''gamma of the setter 21 is set to a value lower than the counterelectromotive voltage of the HM group 6. |
