The ERV 500 series of electronic speed controllers provide an effective means of regulation for voltage controllable single-phase AC motors. It’s categorized according to the ERVs specification i.e. ERV with HRW or PHE & ERV with AC or EC motors. All controllers are electronic based and has ON/OFF switching option along with speed control. It controls the fan voltage by PWM signals to regulate the output voltage with the minimum power loss. It is very highly efficient speed regulator with the precise step regulation using a potentiometer.