What is a Variable Frequency Drive?
A Variable Frequency Drive (VFD) is a power conversion device. The VFD converts a basic fixed frequency, fixed voltage sin-wave power to a variable frequency, variable voltage output used to control speed of induction motors.
A VFD controls the speed of an AC induction motor by controlling the power (voltage and frequency) that supplies the motor. By reducing the motor speed to match the needs of the application, VFDs have the potential to significantly save energy and reduce operating costs for a variety of motor driven applications.
How does a VFD Work?
Frequency (or hertz) is directly related to the motor’s speed (RPMs). In other words, the faster the frequency, the faster the RPMs go. If an application does not require an electric motor to run at full speed, the VFD can be used to ramp down the frequency and voltage to meet the requirements of the electric motor’s load. As the application’s motor speed requirements change, the VFD can simply turn up or down the motor speed to meet the speed requirement.