What is full form of UPS ?

UPS means Uninterrupted Power Supply. It is used for electronic instruments where continuous (or uninterrupted) power supply is required.  It consists of one rectifier, battery &an inverter. Inverters are of various types – On Line, Off Line etc.

Rectifier–

The function of Rectifier is to convert AC into DC & provides battery charging voltage. Its output is connected with battery.

Battery –

The function of battery is to store DC energy in it. Its output is connected with the inverter through a static switch which operates when power goes off.

Inverter –

It converts DC into AC when AC power goes off. It is connected with load.

Working principle –

When normal AC supply is available, load is connected with normal AC supply. AC supply is also connected with rectifier & rectifier converts AC into DC & provides charging voltage for battery. And battery gets charged & DC energy is stored in it. When power goes off, battery is connected with inverter through a static switch (which is off when normal AC power is available) & DC is converted into AC & immediately load gets alternate AC supply. When normal AC supply resumes, the static switch gets open & battery is disconnected with inverter & load is again connected with normal AC supply. Also discharged battery is charged again through rectifier.

 

There are two types of UPSs –  1) Off Line UPS  2) On Line UPS

OFF LINE UPS –

When normal AC supply is available, load is connected with AC mains & batteries are charged (through battery charger) from AC mains to maintain a rated voltage. But when power fails, battery is connected with inverter & inverter converts DC into AC & which is fed to load. When AC supply is restored, battery is disconnected from inverter & load is again connected with normal AC supply. And this procedure is repeated.

ON LINE UPS –

In this case, load is always fed from AC which is coming from inverter. Normal AC supply is connected with charger, charger charges the battery & battery is directly connected with inverter & inverter converts DC into AC.  And load is connected with inverter.