Calculate efficiency at half load & unity power factor in 20 kVA, 2200 / 220 volts transformer where iron & copper losses are given

Q.  In a 20 kVA, 2200 / 220 volts transformer iron and copper losses are 300 and 400 watts respectively. Its efficiency at half load and unity power factor is
- Published on 29 Oct 15

a. 95.11%
b. 96.15%
c. 97.77%
d. 98%

ANSWER: 96.15%
 

    Discussion

  • Amrit Parajuli   -Posted on 23 Jul 21
    We have,
    Efficiency = (KVA * pf)/((KVA * pf) + losses
    For Full load, Copper loss = 400 Watts
    For Half load, Copper loss = 400/4 = 100 Watts
    So Total loss at Half load = Iron loss + copper loss = 300 + 100 = 400 Watts
    Efficiency = 20/(20 + 0.4) = 98%
  • Sushant   -Posted on 01 Sep 18
    The formula is
    Efficiency = KVA * pf / (KVA * pf + iron loss + copper loss)
  • probir mondal   -Posted on 12 Jul 18
    please help me....
  • Venkatesh   -Posted on 08 Jul 18
    What is the formula
  • Aqila   -Posted on 23 Oct 17
    Where is the solution?

Post your comment / Share knowledge


Enter the code shown above:
 
(Note: If you cannot read the numbers in the above image, reload the page to generate a new one.)