How does a VFD control the speed of an AC motor?
A. By changing the voltage and frequency of the power supplied to the motor
B. By adjusting the mechanical load on the motor
C. By changing the size of the motor
D. By adjusting the resistance of the motor
Answer:A
How does a VFD control the speed of an AC motor?
A. By changing the voltage and frequency of the power supplied to the motor B. By adjusting the mechanical load on the motor C. By changing the size of the motor D. By adjusting the resistance of the motor
Explanation: A VFD controls the speed of an AC motor by adjusting the voltage and frequency of the power supplied to the motor. By increasing the voltage and frequency, the VFD can increase the speed of the motor, and by decreasing the voltage and frequency, the VFD can decrease the speed of the motor. This is achieved by changing the input voltage and frequency to the inverter section of the VFD, which then applies the appropriate voltage and frequency to the motor.