Variable frequency drives are extensively used devices meant for controlling electrical energy utilization at optimum cost. These are also called variable speed drives, adjustable speed or frequency drives, AC drives, and inverters. Previously, valves and slats were used to control the flow of fluids in electric motor drives which were energy intensive. Variable frequency drives help to establish an efficient mode of controlling the electrical load. Variable frequency drives (VFD) are the most effective and efficient motor controllers in the industry today. Modern VFDs are affordable, provide smooth motor acceleration, are reliable, reduce power supply problems in the facility, and have flexibility of control. Further, the use of VFD brings the total system cost down because of the elimination of various system components which are required for valve control. Variable frequency drives are also used when three phase motors are needed to be operated from single phase power so that there is minimum wastage of power.