| 摘要 |
PURPOSE:To enable the excessive speed of a motor to be suppressed without stopping the motor, by decelerating the motor when the present acceleration rate of the motor becomes greater than an acceleration rate at the time of normal rotation. CONSTITUTION:On every sampling pulse constant-time, a speed is detected, and a difference between a speed before one sampling and the momentary value of a present motor-speed is computed by a subtracter 11, and an acceleration rate is computed. When the acceleration rate is greater than an acceleration rate at a normal time, then the output of overspeed state signal 14 is generated. Then, subject to the generated output of signal 17 that the present speed of a motor 19 is greater than a reference speed, the output of deceleration command signal 22 that the speed of the motor 19 is decelerated up to the reference speed is generated. As a result, before the motor comes to an overspeed, the motor is decelerated, and as it is, working can be continuously performed. |
