DER-637, Possibility of using, 60Hz input? Posted by: LEE WOO JIN on Tue, 03/09/2021 Hi. DER-637 is written, Condition of input, 140 ~ 320V, 50Hz. Can I apply this design at 220V, 60Hz? If not, Is there any guide to accommodate for the 60Hz? Log in or register to post comments Comments Hi Lee Woo Jin, Using 60Hz as line frequency can still be applied but the THD and power factor will be affected. It was not tested on the design. If these parameters were affected and not able to meet your desired criteria, the input filtering components should be redesigned or optimized to meet the target requirements.