What Is A Variable Frequency Drive?

Are you looking to lower your building's electric costs? Or how about increasing the life expectancy of your motors while simultaneously reducing the cost of maintenance? Do you have ac motors in your facility? Do these motors need a variable output? Do you use mechanical means to vary the output? If you answered yes to any of these questions, a Variable Frequency Drive (V.F.D.) or Variable Speed Drive (V.S.D.) is your answer.

A variable-frequency drive (VFD) is a system for controlling the rotational speed of an alternating current (AC) electric motor by controlling the frequency of the electrical power supplied to the motor. A variable frequency drive is a specific type of adjustable-speed drive. Variable-frequency drives are also known as adjustable-frequency drives (AFD), variable-speed drives (VSD), AC drives, microdrives or inverter drives. Since the voltage is varied along with frequency, these are sometimes also called VVVF (variable voltage variable frequency) drives.

V.F.D.'s convert three phase, 60Hz to an adjustable frequency and voltage, for controlling the speed of an induction motor. The speed of the motor is proportional to the applied frequency. The frequency is varied by the Direct Digital Control System.

Variable-frequency drives are widely used. For example, in ventilation systems for large buildings, variable-frequency motors on fans save energy by allowing the volume of air moved to match the system demand. Variable frequency drives are also used on pumps and machine tool drives.

Benefits of using a V.F.D. include:

• Soft-Start - Adjustable accelerations, reduced horsepower on initial start-up, less wear and tear on motor belts, couplings and bearings.
• Adjustable Speed - Energy savings and precision control.
• Reduction of Harmonics - While increasing power factor.
  

We carry a full line of VFD's from SquareD. If you are interested in learning more, send us an email at customer_service@midwestbas.com

Thank you for your patronage,

The MidwestBAS Team