Variable Frequency Drives (VFDs) is an electronic device that converts an alternating current of one frequency to another frequency that gives an opportunity to run the AC motors in variable speed and also provide an opportunity for saving power on many industrial applications.
It is a green saving product that matches the amount of workload on a motor to the amount of energy it needs to power that amount of work. It saves power in multiple ways and the degree of saving depends upon the applications, the drive features, and the drive set-up. There are some ways that VFD is used to save power across industries:
Built-in Power Factor Correction
There are many facilities that have power factor correction capacitors at the service and they also put them there only to escape a Power Factor (PF) penalty from the electric utility. They are wasting power back at the load because of low power factor and a power factor corrected device eliminates all or nearly all of this waste.
Built-in Harmonics Correction
Harmonics waste energy and also cause a motor to run hotter and sometimes a lot hotter and rendering the motor to be less efficient. Correct for excess harmonics and your motor lasts longer and uses less energy.
This feature is a standard VFD feature and when properly set-up, it will not only extend the life of the motor but also reduces its power usage and the deadly effect on the whole distribution system across the line.
Speed Control on the Input
It’s really application-specific. You still want the gearbox for torque multiplication, and something a variable frequency drive can’t give you. You can save power if you simply reduce the motor speed rather than dissipating the work already done by the motor.
Continuous Drive Instead of ON/OFF
This is also an application-specific; for example, a motor is oversized to meet some idea of a maximum load but in reality, is never there. The motor cycles on and off and the variable frequency drive effectively right-size the motor to the load, actually driving by throttling it back.
A VFD is able to save power with the help of the above effective ways and it saves power because it consumes the power that’s needed across different application usage points.