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Transformer Problem

  1. Aug 9, 2010 #1
    Hi friends

    If I have three phase 250 kva Transformer, 440 input and 220 output then
    Can I say that it can bear 568.2 amp current or 1136.3 amps?
  2. jcsd
  3. Aug 9, 2010 #2


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    Your transformer can provide 250kva to a load. So you'd have 250kva/220v.

    Assuming your "output" is where the load is attached.
  4. Aug 9, 2010 #3
    It can bear 328 amp current in input side(440 V) and 656 amps in output(220V).

    S input=S output
    Last edited: Aug 10, 2010
  5. Aug 10, 2010 #4

    how can you calculate. you use S=VI
  6. Aug 10, 2010 #5


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    I probably should wait for m.s.j to answer here. S = 3 phase VA (volt-amps) = V*I*sqrt(3). Sorry I didn't include the sqrt(3)=1.73 required in the equation since you were asking about 3 phase.
    I totally missed that the OP said "three phase". Thanks for the sqrt(3).
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