An On-line UPS is a type of uninterruptible power supply that utilizes either a
double or delta conversion technology. With double conversion, network
equipment does not receive electricity directly from the AC outlet. Instead, AC
power travels to a rectifer, where it becomes DC power. Next, it travels to the
battery, and then an inverter. After inversion back to AC, the power is
delivered to equipment. With this online UPS device process, computing
equipment receives continually clean power. With delta conversion, a certain
amount of power is sent to run computers, routers and other equipment directly.
This creates an energy efficient online UPS system where some of the power
skips the processing steps.