| 摘要 |
PURPOSE:To shorten a rise time by providing an accelerating time constant changing circuit, thereby stepwisely accelerating of an induction motor. CONSTITUTION:When a speed setting voltage Vm is raised, a slip increases, and the current of an induction motor 3 increases. When this current exceeds the current limit value for deciding the switching point of the accelerating time constant of a current limit setter 13, a comparison discriminator 14 is operated to operate the contact output group of a sequence circuit 15. A slow starting circuit 12 outputs a speed command voltage V by the input from a speed setter 11 and the operation of the contact group of the circuit 15 while stepwisely changing the accelerating time constant to an inverter. In this manner, when an overcurrent is produced as shown, the acceleration is temporarily stopped for the prescribed time, and is again operated. |
