| 摘要 |
PURPOSE:To effectively automatically restart many hysteresis motors after a power source is recovered by detecting a counter-electromotive force of a common section of the motors at the time of a power interruption, resetting the output frequency of a VVVF inverter, and operating the inverter with the frequency at the time of recovery of the power source. CONSTITUTION:A power source interruption is detected by a power source interruption detector 2 at the time of a power interruption, a power source interruption signal is output to a controller 3, and a VVVF inverter 1 is stopped. A counter-electromotive force of a common section of hysteresis motors 4a, 4n is input to a counter-electromotive force detector 6 through a transformer 14, and a rotating speed obtained by the detector 6 is output to a frequency setter. At the time of recovery from the power source interruption, the signal is eliminated, and the inverter 1 is operated without load. An average current vector difference detector 5 judges whether an abnormal signal is detected or not. If the abnormal signal is not detected, a switch 10 is applied by an application signal from a load application controller thereby to automatically restart it. |
