How to Control Motor Speed Using VFD? How it Help in Energy Efficiency?

What is a VFD?

What is a VFD?A VFD (Variable Frequency Drive) is a type of motor controller. It drives an electric motor by varying the frequency and voltage supplied to the electric motor. There are many other names of VFD that are variable speed drive, adjustable speed drive, adjustable frequency drive, AC drive, inverter, and Microdrive.

It can be used to change the out speed of an AC motor by adjusting the input frequency into the motor. By using a variable frequency drive with an AC motor, speed can be adjusted easily and this is the most common reason for using them. VFD allows the minimum and maximum speed to be adjusted, an application is running at.

How VFD (Variable Frequency Drive) Control the Speed of an AC Motor?

There are three factors that can alter an AC motor speed that is a number of poles, frequency and load and below, I’m discussing these three sections:

  • Magnetic Poles
    AC motors have magnetic poles as part of their construction and it cannot change after they are built and the speed of the AC motor will remain relatively consistent regardless of the application’s torque.
  • Frequency
    When the motor is run you can control the speed of an AC motor by changing the frequency. If the motor is not provided to run on the necessary frequency provided then it’s recommended to simply change the frequency of the motor that could cause many issues including overheating and loss of power. By changing the frequency of the motor, Variable frequency drives can change the speed of an AC motor and it also doesn’t sacrifice the speed of the motor. It’s done by porting the speed port of an AC motor drive.
  • Load
    When you choose a VFD to use with a motor then the right selection of it will depend on the operation load requirement of the application. In this application, the higher the load and more torque, higher the current draw of the motor will be needed. It means the VFD is rated by their continuous output current, and for the optimal performance it is important to select a drive with adequate current available to the motor.These are the processes of controlling the speed of an AC motor by using VFD (variable Frequency Drive), and thereby these make for a highly important energy efficient necessity for electrical motors across industries.