Difference between Inverter and UPS

Discussion in 'Computer Accessories' started by gardencityboy, Jun 19, 2008.

  1. gardencityboy

    gardencityboy New Member

    I have seen many companies which sell UPS and Inverter
    What is the exact difference b/w a UPS and an inverter

    I know both of them convert DC to AC but what is the exact difference

    I was going through the SU-KAM website and they sell both UPS and invertor, not sure what is the difference
  2. just4kix

    just4kix Guardian Angel Staff Member

    The basic difference in layman's terms is:

    While both provide backup power during mains outage, with the UPS the switch is instantaneous whereas with the Inverter there is a gap of a second or two. This gap is OK for household gadgets such as lights, fans, fridge, etc. but not OK for computers.

    In technical terms:

    UPS: The mains power comes to the UPS. The AC is converted to DC and this DC is constantly charging the battery. The output of the battery is fed to the Sine wave inverter and it converts DC to AC and this feeds the equipment. Since power out is always drawn from the battery, there is no time lag when mains swicthes off; it justs stops the battery from being charged and the UPS continues to supply power till the battery runs out.

    Inverter: The mains power comes to the Inverter. This is directly sent to the output but the AC is also converted to DC and this DC is constantly charging the battery. A sensor and relay mechanism checks whether the mains is ON or OFF. When the main switches OFF, the relay actuator triggers to switch from mains to inverter. Rest is same like the UPS. Because of this sensor and relay, there is a gap between triggering.

    UPS involves more costly circuitary and is therefor more expensive to make and sell.
  3. gardencityboy

    gardencityboy New Member

    Thanks a lot
    you have made it crystal clear
  4. Admin

    Admin Administrator Staff Member

    Thanks for the valuable info :)
  5. player

    player New Member

    cheers to just4kix!!!
  6. aktmnr

    aktmnr New Member

    Just to add to this valuable info UPS provides the pure sine wave AC but this is not in the case of Inverter so there are chances that Inverter might damage the complex electronic circuitry of computer.
  7. gardencityboy

    gardencityboy New Member

    Actually there are inverters from SU KAM which come with pure sine wave, so no problems with that
  8. aktmnr

    aktmnr New Member

    Yep and thats why they even claim in their Ads that you can use it to run computers...
  9. player

    player New Member

    these inverters are called online UPS and they are very costly comparing to normal sinewave inverters
  10. just4kix

    just4kix Guardian Angel Staff Member

    ... as long as there is no delay in switchover.

    You know what ... now the major cost in a UPS or Invertor is not the device itself but the batteries. It appears that batteries have become extremely expensive. From what I heard, now batteries' cost is almost 70% is an invertor that gives 1 KVA backup for 4 hours.
  11. just4kix

    just4kix Guardian Angel Staff Member

    The guy who maintains the inverters in our apartment block has advised me a small 500VA UPS for my projector. He told me that in case of sudden power interruption, my projector will switch off at full lamp heat and consequently damage the lamp or reduce its life. Also, the UPS will by itself act as a voltage stablizer.
  12. gardencityboy

    gardencityboy New Member

    i agree with you
    i just inquired about the UPS and SU KAM said that a local batter UPS will cost Rs 13000 for 800 VA and Rs 17000 for Exide battery, which is huge difference
  13. anniiee

    anniiee New Member

    That was the good one:cool:!!!
  14. madhu2008

    madhu2008 New Member

    thanks a lot for valuable information
  15. pothi

    pothi Member

    My situation is somewhat unique. I bought a UPS (with 10+ min backup) along with my laptop. Then due to frequent power cuts, I was forced to get a better backup. Then I bought an inverter with 10+ hours back up. What I have done with the inverter and UPS is this,

    The Main Power Supply -> Inverter -> UPS -> PC/Laptop.

    So when the power fails, I still have power (I mean without any delay) from UPS for my PC/laptop. Of course, the UPS would be off for a fraction of a second before it gets power from inverter when the power goes off from the mains.
  16. gurusam

    gurusam New Member

    Hmm nice trick pothi..
  17. tejiyas

    tejiyas New Member


    I made another post asking the answer to the question originally discussed in the first post of this thread. Thanks.

    So if I understand this correctly, if you have a regular su-kam type of sineway inverter but no ups, when the main goes off the computer will also go off. On my su-kam there is a choice of PC. I did not want to experiment using it yet till I discussed it here. If I switch the inverter to PC, then still there will be a slight gap in time, my computer will shut down if there is no regular UPS? Am I right or wrong. The second thing I read is that the regular sine wav inverters do not out pure sinewave dc and thus can damage the computer. Those who are tech smart can confirm or correct me please. Thanks.

    I have a second question that I bought a proview ups. It is 600VA. I have a desktop computer with a 17"CRT, and 2 hard drives. The UPS proview never lasted more than 3 minutes. Is this normal for proview, or really wrong? I keep reading that other guys get 15 minutes of up time with a similar setup as I have.

    Last question is that my inverter has a 165G Tata battery with six regular cells and is 600V. Right now if I keep on just the computer and one light I get max of 2 hours. Is this right or is my battery on the way out. The guy we bought it from is, well, not my choice the next time.

    Many thanks
  18. sinstoic

    sinstoic New Member

    Difference between UPS and Inverters

    A Uninterruptible Power Supply (UPS) broadly consists of:

    1. Rectifier (Charger) - To convert AC Power (from Power Grid) to DC Power (to charge Battery)

    2. Inverter - To convert DC Power (from Battery) to AC Power (to power load i.e., electrical and electronic equipment.)

    3. Controller - To control functions of Rectifier (Charger) and Inverter. (i.e., when to start or stop charging battery, when to start or stop power from battery to load, how fast to change from Grid Power to Battery Power and so on)

    An Inverter broadly consists of:

    1. Inverter - To convert DC Power (from Battery) to AC Power (to power load i.e., electrical and electronic equipment.)

    2. Controller - To control functions of Inverter. (i.e., when to start or stop power from battery to load and so on)

    Inverters are usually used with Solar Photovoltaic Cells/Modules (Solar Panels) or Windmills, which directly generate DC Power to charge batteries and therefore no Rectifiers are required.

    Batteries be directly charged via Battery Chargers. Typically, hawkers in India use Inverters to power light sources. At the end of the day, they give their batteries for charging.


    1. Change over time from Grid Power to Battery Power is typically set to less than 10 milliseconds to avoid sensitive electronic equipment and computers from rebooting. As change over time is set in Controller, both UPS and Inverters can run sensitive electronic equipment and computers.

    2. DC Power from Battery is converted to AC Power for load in either Pure Sine (Sinusoidal) Wave (Waveform) or Modified Sine Wave. Pure Sine Wave is ideal and recommended for increasing life of electrical and electronic equipment and is a must for sensitive electronic equipment. Modified Sine Wave damages electrical and electronic equipment over a period of time and generates humming noise from load during operation. Both UPS and Inverters can generate either Pure Sine Wave or Modified Sine Wave.


    Indians typically call a device:


    • when it has a built-in battery

    • when it has a short backup duration

    • when it is used in Office

    • when it is not used for lighting purposes

    • when it is used for computers

    • when it does not reboot computer

    • when its output is pure sine wave


    • when it has an external battery

    • when it has a long backup duration

    • when it is used in Home

    • when it is used for lighting purposes

    • when it is not used for computers

    • when it reboots computer

    • when its output is modified sine wave

    Sometimes Inverters with the above features are incorrectly called Invertors (word not in dictionary).

    Published with permission from Mr. Kamath, Archenergy, Mysore
    Source: Archenergy - www . archenergy . in
    Last edited: Sep 13, 2009
  19. meetdilip

    meetdilip The Wizard

    Good one................
  20. imrock

    imrock The Master

    an inverter has a long battery back up whereas ups has little.

    also ups is computer ups but inverter is home ups.

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