Description:

• The frequency of the motor supply voltage is changed by a frequency converter using a U/F scalar control method to adjust the rotational speed.
• The rotational speed is controlled by varying the frequency of the power supply to the motor windings.
• The voltage supplied to the motor terminals can be modified in accordance with the frequency changes in order to maintain almost constant torque.
• Thus, the only thing a scalar frequency converter can do is supply the motor terminals with voltage at a particular frequency.
• The motor shaft's rotation speed is not directly proportional to frequency because of slip, which is the difference between the speed of the shaft's rotation and the speed of the motor's field.