charging issue

Discussion in 'General Electronics Chat' started by shahnawaz, May 29, 2012.

  1. shahnawaz

    Thread Starter Active Member

    Dec 30, 2008
    37
    0
    hi all,

    i am testing a 2kva UPS and facing one problem. so need your help.
    actually the UPS is consists of a 2kva transformer, FET circuits, and an overload circuit. when i gives commercial power to UPS then UPS battery charger charges the battery very well. but if i gave another 5KVA UPS output to this 2kva UPS as Commercial input then the charger does not charge the battery. i cant understand why the battery charger does not work on that input 220 vac taken from another 5kva UPS. please remember that the 5kva UPS output is a square wave.

    thanks for the help in advance.
     
  2. #12

    Expert

    Nov 30, 2010
    16,270
    6,784
    You answered your own question.

     
  3. shahnawaz

    Thread Starter Active Member

    Dec 30, 2008
    37
    0
    please explain. i can naot understande what u meant.
     
  4. #12

    Expert

    Nov 30, 2010
    16,270
    6,784
    A square wave does naot have the peak voltage of a sine wave.
    A square wave can naot be rectified to get the peak voltage of a sine wave.
    Naot achieving the peak voltage will naot charge the battery.
     
  5. strantor

    AAC Fanatic!

    Oct 3, 2010
    4,302
    1,988
    you're naot powering the 5KVA UP with the output of the 2KVA UPS are you?
     
    #12 likes this.
  6. #12

    Expert

    Nov 30, 2010
    16,270
    6,784
    He's trying to use a 5KVA, square wave output, to charge the battery in a 2KVA UPS. The problem is that a square wave does not have the same peak voltage as a sine wave of similar RMS voltage. After rectification, the peak voltage is not high enough.

    ps, I always give a "Thanks" for an LOL.
     
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