The Standby On-Line Hybrid is the
topology used for many of the UPS under 10kVA which are labeled
"online." The standby DC to DC converter from the battery is switched
on when an AC power failure is detected, just like in a standby UPS. The
battery charger is also small, as in the standby UPS. Due to capacitors in the
DC combiner, the UPS will exhibit no transfer time during an AC power failure.
This design is sometimes fitted with an additional transfer switch for bypass
during a malfunction or overload. Figure 3 illustrates this topology.

