Safe And Effective Frequency converter,frequency converter,frequency to voltage converter,voltage to frequency converter,siemens vfds,frequency changer,A frequency converter is an electrical device that converts current at one frequency to another. Modern frequency converter inverters use a technique called “Pulse Width Modulation” (PWM) to regulate voltage and frequency. Purchase an inverter to change 110v/120v 60Hz to 208v/220V/230V/240V 50Hz through a built-in transformer, up to 400Hz, converting fixed hertz to variable hertz power.