Online Double Conversion

Double Conversion On-Line UPS is the same as the Standby UPS except that the primary power path is the inverter instead of the AC mains. In the design of Double Conversion On-Line operation, failure of the input AC does not cause activation of the transfer switch, because the input AC is not the primary source, but is rather the backup source. Therefore, during an input AC power failure, on line operation results in no transfer time. The on line mode of operation exhibits a transfer time when the power from the primary battery charger/battery/inverter power path fails. This can occur when any of the blocks in this power path fail.