What Is The Advantage of Online UPS over Off Line UPS?

The main difference between Online UPS and Offline UPS is that Online UPS provides power with the help of a rectifier and inverter combination. It simultaneously provides power to load as well as the battery so that battery can be charged to supply power in case of power failure.

Advantages of Online UPS:

• It provides isolation between main supply and load.

• Since inverter is always ON, the quality of load voltage is free from distortion

• All the disturbances of supply such as blackout, brownouts, spikes etc are absent in the output.

• Voltage regulation is better

• Transfer time is practically zero since inverter is always ON.

Disadvantages of Online UPS:

• Overall efficiency of UPS is reduced since inverter is always ON.

• The wattage of the rectifier is increased since it has to supply power to inverter as well as charge battery

• Online UPS is costlier than other Uninterruptible Power Supply Systems.

Applications of Online UPS:

• Induction motor drives and similar other motor control applications.

• Intensive care units, medical equipments.

Advantages of Offline UPS:

• Offline UPS has high efficiencies, since charger is not continuously on.

• The power handling capacity of charger is reduced.

• Offline UPS are not very costly.

• Internal control is simpler in offline Uninterruptible Power Supply.

Disadvantage of Offline UPS:

• Since offline UPS provides mains supply when it is present, the output contains voltage spikes, brownouts, blackouts.

• There is finite transfer time from mains to inverter when mains supply fails.

• Output of offline Uninterruptible Power Supply is not perfectly reliable.

Applications of Offline UPS:

• Computers, printers, scanners etc use offline UPS.

• Server,workstation,data center.