As energy conservation, optimization and asset management become topics that have finally come to the forefront and become priority to systems in our industry; many have not made the changes to reflect the epiphany that has been realized. In other words, you know something needs to be done and it is beneficial, but your system, municipality, or plant just has not implemented the technology. An easy way to start energy conservation is by installing variable frequency drives (VFD) on pumps, motors and other equipment. A VFD is merely a power conversion device that converts the fixed voltage and frequency of incoming power to a variable voltage and frequency output to provide the variable speed capabilities. If the motor is operating at half the speed and producing full torque, the motor is outputting half of its rated power. Consequently, if the motor is running at full speed and producing half torque, the motor is also outputting half of its rated power.
There are several different types of VFDs. The pulse width modulation is the most popular. It is effective over a large range from ½ hp. to 500 hp. motors. They are affordable and reflect the least amount of harmonics back to its power source. The highest efficiencies have been recorded between 92 -96 percent. The following video describes what VFDs are and exactly how they save you money.