Do you lose torque with a VFD?
Will the torque decrease after the motor is added to the frequency converter? First, we need to analyze this problem theoretically.
Under the control of the frequency converter, the motor frequency and voltage will change, thereby achieving the effect of energy saving and consumption reduction. The frequency converter controls the motor speed and torque by continuously adjusting the output frequency. What needs to be noted here is that the frequency modulation ratio of the frequency converter is not linearly related to the motor speed. Generally speaking, when the motor operates at rated voltage and frequency, the torque is the rated torque. Under the regulation of the inverter, the voltage and frequency of the motor when running are not the rated voltage and frequency. Therefore, the actual output torque will be smaller.
In addition, the error of the frequency converter will also affect the torque output. The control algorithm of the frequency converter is calculated based on instantaneous speed, instantaneous voltage and current. Factors such as wiring and cable impedance may interfere with the signal transmission of the inverter, thus affecting the accuracy and stability of the torque output.
Next, we verify this theory from the perspective of practical application. For some equipment that requires high-precision control, such as industrial machinery, elevators, etc., frequency converters are usually used to control motors. In this case, the torque output will be affected by factors such as the inverter control algorithm and signal transmission, resulting in a reduction in torque. In some other applications, such as ventilation equipment, water pumps, etc., high-precision control is generally not required. Therefore, after the motor is added to the frequency converter, the impact of torque reduction is small or even negligible.
Generally speaking, after the motor is added to the frequency converter, the torque output will be affected to a certain extent. The specific impact depends on factors such as the accuracy of the inverter control algorithm, the stability of signal transmission, and the specific application requirements of the equipment.