A VFD (Variable Frequency Drive) is an automation device which is used to control the speed of the motor. Nowadays, due to use of PLC in industrial automation panels, a variable speed motor will be required to be handled by PLC. But, due to VFD in between; the PLC will control VFD first and then the motor will be controlled by the VFD. This is the most basic thing that many beginners fail to understand on why a VFD needs to be controlled by a PLC in order to handle the operation of motor.
