| 摘要 |
PURPOSE:To protect an inverter-composed element against a damage due to an overcurrent by judging whether the frequency supplied by an inverter to a motor is a predetermined value or not to prevent an improper frequency from being supplied to the motor. CONSTITUTION:The rotating speed per unit time of a minimum inertial moment, i.e., the maximum change rate of the frequency corresponding to the real rotating speed of a rotor is stored. When there is a variation in the frequency transiently larger than this change rate, this frequency is ignored to eliminate the damage of the inverter due to the overcurrent. |
