| 摘要 |
PURPOSE:To prevent the occurrence of hunting, etc., by storing the time until a set frequency is reached after acceleration or deceleration starting time and the frequency difference between a set frequency and the frequency at the acceleration or deceleration starting time. CONSTITUTION:The inclination S1 of an output frequency is calculated based on the output frequency difference of an inverter 2 at the preceding accelerating or decelerating time and the time required for the acceleration or deceleration and the current acceleration or deceleration is performed in accordance with the inclination S1. When the output T of a torque computing element 7 exceeds a preset limit value (on the driving side) during the acceleration, the acceleration is stopped and, when the torque T becomes equal to or smaller than the limit value, the acceleration is again started in accordance with the inclination S1. Thus a step-like acceleration curve shown by the solid line in the Figure is obtained and the time tA, actually required for the acceleration and an output frequency difference (against a set frequency fs) are stored in an appropriate storing element so as to find the inclination S1 of the next time. |
