What's online UPS?

An online UPS uses a "double conversion" method of accepting AC input, rectifying to DC for passing through the  rechargeable battery then inverting back to 120 V/230 V AC for powering the protected equipment. In an online UPS, the input AC is charging the backup battery source which provides power to the output inverter, so the failure  of the input AC won't cause activation of the transfer switch. That is to say, if a power loss occurs, the rectifier will simply drop  out of the circuit and the batteries will keep the power steady and unchanged. No transfer time during the failure. When power  is restored, the rectifier will resume carrying most of the load and begin charging the batteries, though the charging current  may be limited to prevent the high-power rectifier from overheating the batteries and boiling off the electrolyte. Although the initial cost of an online UPS system is greater than a line interactive system, the total cost of ownership (TCO) is  generally lower as the batteries tend to last longer.

Specializing in online UPS NASN Power provides a number of online double conversion UPS systems including rack mount options, tower version, from 1kVA to 1000kVA with a vast array of applications and features. Ranges include high frequency and low frequency type.