VFD stands for variable frequency drive. While selecting a VFD, various kinds of things have to be taken into consideration, though the most important factors remain current and voltage selections. Depending on the selections, there are different names for the drives like adjustable speed drive, variable speed drive, inverter and micro drive. With innumerable variable frequency drive dealers in the market, it is important to choose the right product so that your purpose is served in the best manner. The main function of a VFD is to convert an ac power source to a dc power source. The speed control part of the drive utilizes the dc voltage for creating dc pulses in varying frequencies for driving the output motor at varying speeds.