What is Uninterrupted Power Supply?

This article gives the information of “Uninterrupted Power Supply (UPS)”. UPS is a device connected between the electric power source and computer to ensure that electrical flow is not interrupted. An uninterrupted power supply (UPS) also known as an Uninterrupted Power Source or a battery backup is a device which maintains a continuous supply of electric power to connected equipment by supplying power from a separate source when utility power is not available. An alternative power source, usually a set of batteries, used to power a computer if the normal power services is interrupted or fails below acceptable levels.

A UPS can often supply power for just long enough to let you shutdown the computer in an orderly fashion. It is not designed to support long term operations. In addition to protection from short power irregularities you may need backup power. Sometimes lighting storm will or destroy power for just a second, which is enough to erase the data in computer’s temporary memory. Thus the total loss of power can be avoided with batter based power system. Such power system is called as “Uninterrupted Power Supply (UPS)”.

UPS generally protect the computer against four different power supplies:

  • Voltages surges and spikes: Times when the voltage on the line is greater than it should be.
  •  Voltage sags: when some Times comes the voltage on the line is less than it should be.
  • Total power failure: When some Times a line goes down or a fuse blows somewhere on the grid or in the building.
  • Frequency differences:  When some Times the power is oscillating at something other than 50Hertz.



There are various common power problems that UPS units are need to correct. They are as follow:

  1. Power failure: Total loss of utility power causes electrical equipment to stop working.
  2. Voltage sag: Transient (short term) under voltage causes flickering of light.
  3. Voltage spike: Transient (short term) over voltage i.e. spikes or peak causes wear or acute damage to electronic equipment.
  4. Under voltage (brownout): Low line voltage for external period of time: causes overheating of motor.
  5. Over voltage: Increased voltage for an extended period of Time: Causes light bulbs to fail.
  6. Line noise: Distortions superimposed on the power waveform: causes electromagnetic interference.
  7.  Frequency variation: Deviation from the nominal frequency (50 or 60 Hz) causes motor to increased or decreased speed.
  8. Harmonic distortion: Multiples of power frequency superimposed on the power waveform causes heating in writing and fuses.


Uninterrupted Power Supply



There are two distinct types of UPS:

  1. Offline (stand by UPS) and
  2. Line interactive (also called on line or continuous UPS)



The standby UPS is the most common type used for personal computers.  The advantage of stand by UPS or offline UPS is it having lower in cost to online UPS. And the disadvantage of stand by UPS or offline UPS is high switching is required otherwise there is possibility that cut in power and reboot the system.


The online UPS sometimes called a true UPS. In the online the primary source is the UPS’s battery and utility power is the secondary power supply.

Sourabh Bhunje

Sourabh Bhunje, B.E. IT from Pune University. Currently Working at Techliebe. Professional Skills: Programming - Software & Mobile, Web & Graphic Design, Localization, Content Writing, Sub-Titling etc. http://techliebe.com/about-us

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