What is output frequency sync to mains?

this always used in inverters and UPS As in standby UPS And line interactive UPS ,the output frequency must be always track the input frequency as it supply the load from utility in standby mode, for any change that will affect the load .

as example the frequency of the utility was with permitted values say 58Hz and suddenly the main power cutout, so UPS must be on same frequency so when convert to backup stored power mode ,the load doesn't affected and power continue to supply the load from the batterys through inverter , so output frequency must be always synchronized to utility frequency (mains) in case of any fault happened, hope i answered your question.

Sherif Salah

R & D Engineer at Arrow Electronics

Egypt