In open-loop operation, the inverter outputs the specified frequency, while the motor's speed fluctuates within the range of the rated slip rate (1%-5%) during operation with a load. In situations where precise control accuracy at high speeds is required, even when there are changes in load, and the motor needs to operate close to the specified speed, a variable-frequency drive equipped with a PG feedback function (optional accessory) can be utilized along with selecting the closed-loop vector control mode.