| 摘要 |
PURPOSE:To smoothly re-start operation after instantaneous stop, by resetting the output of a magnetic flux regulating means slowly at the point of time when the residual flux of a motor is reduced to come to a specified value or less on the instantaneous stop, and after that, by applying a magnetic flux command value and a frequency command value to. CONSTITUTION:When the residual flux of an induction motor 10 comes to a value approximating zero or lese on instantaneous stop and the output of signal H is generated from a logical circuit 34, then a PWM inverter 9 and the induction motor 10 are combined with each other. When a time is beyond the limit of the time set by a timer 35, than the output of a first slow reset circuit 36 starts increasing, and the amplitude of a magnetic flux command value starts increasing from zero. By a current transformer 22, current to the induction motor 10 is detected, and via a frequency changing circuit 23, to an acceleration or deceleration arithmetic circuit 2, the change of a frequency command value is commanded. |
