| 摘要 |
PURPOSE:To prevent the excessive running in the reverse direction at deceleration by employing a speed sensor utilizing a one-phase pulse generator which does not sense the direction an AC tachogenerator, and realizing four-quadrant running of the induction motor. CONSTITUTION:In the case a speed setter 6 having two polarities is employed, the speed reference is converted into the one-way voltage V2 by an absolute-value converter 20. The output V1 of the speed reference setter is supplied to a polarity identifying unit 30, where the polarity is identified. Then, a logic 40 is added, and a forward running signal F is obtained. The output of the polarity identifying unit 30 is connected to the circuits of SR, F, and R in the figure as a reverse running signal R. Thus, an induction motor can be run in the forward and reverse directions at the speed reference having two polarities. If the output of an AC tachogeneator is rectified and used instead of a pulse generator, a frequency-voltage converter can be omitted. |
