You don't want to find your data lost when the mains power supply gets cut off suddenly?
UPS  (Uninterruptible Power Supply) helps to maintain continuity of power to the servers and
workstations as well as standalone PCs and helps to save the data. UPS also protects the
computer  system from power brownouts,swells, sags, and interface.UPS power supplies switch
on automatically to provide continuous and uninterrupted power to the computer systems.

Components of the UPS

When the mains power supply fails the UPS automatically provides power to the computer system.
It is attached to the Servers, workstations or standalone computers where sensitive work is carried
on and who need protection from power failures. The main components of the UPS are :

1) DC Battery Array or pack.
2) Electronic charger circuit.
3) Converter circuit.

Besides this there are also circuits for automatically changing over from battery to the load and
vice-versa.


Working of UPS - Online UPS and Offline UPS

1) Online UPS --

In on-line UPS the main input AC voltage is converted into low Value DC voltage and then converted
back by means of the inverter to the high value AC voltage. The low value DC voltage is used to
charge the batteries. Even in case the main supply is available the power is supplied to the computer
systems through the UPS. In case of power failure the DC Voltage is supplied by the batteries. It
comes back automatically to the normal status when the main supply recovers. In general online
UPS is used in servers, mini or main frame computer systems.

2) Offline UPS --

In offline UPS battery charger and inverter are two separate parts, doing their jobs independently.
When the power is available through the mains the battery charger is only charging the battery and
the inverter is on stand-by mode. In case of mains power supply interruption the batteries are
connected to the inverter through a relay change over and the current is supplied to the computer
systems. It supplies raw power and does not regulate the input frequency. In this system backup
 time is very low.



Technical specifications:

How will you select the UPS: there are a few technical specifications which you can check.

1. There should be an audible alarm in case of Mains failure, low battery or overload conditions.

2. There must be visual leds for power-on, backup-on or overload.

3. Back up time must be at least half hour - for saving all the data.

4. The input/output voltage range must be wide so that it can absorb any fluctuations.

5. Batteries should be good and maintenance free.

6. Charging time of batteries must be small.

7. UPS should be noiseless.

8. It should have the proper capacity to sustain the load of the entire system.