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Question
What is the formula for calculating Transformer Losses & 
Efficiency. I want to compare the Transformer efficiency at 
different loading condition.
 Question Submitted By :: Electrical-Engineering
I also faced this Question!!     Answer Posted By  
 
Answer
# 1
Efficiency = (Output/Input)*100
&
Output (KW)= KVA * Power Factor
Input = Output + Iron losses + Copper losses
Iron losses are due to Primary voltage so remains constant
can be calculated by open circuit test
Copper losses are due to secondary current I*I*R
can be calculated by short circuit test
Exp: Full load copper losses 800 W
1/2 load copper losses will be 200 watts
 
Is This Answer Correct ?    239 Yes 64 No
Kashifhabib
 
Answer
# 2
Efficiency = (Output/Input)*100
output=(x)(KVA * Power Factor)
input=(x)(KVA * Power Factor)+(X)^2 copperlosses+core losses

the volue of x depend on load
x=1 for full load
x=0.75 for (3/4)th load
x=0.5 for half load
x=0.25 for quarter load

copper losses are variable losses and iron losses are
constant losses.

at the time of full load copperlosses=iron losse
Full load copper losses 800 W
half load copper losses=(X)^2 copperlosses
x=0.5 for half load
=(0.5)^2 *400
=0.25*400
half load copper losses=200
 
Is This Answer Correct ?    126 Yes 52 No
Vinod Parasa
 
 
 
Answer
# 3
POWER Transformer is 55MVA, 27/11.5KV ,efficiency =99.49

Find the Losses of Transformer
 
Is This Answer Correct ?    39 Yes 16 No
N.makali
 
Answer
# 4
Efficiency =
(Output/Output+Iron losses+Copper losses)*100
Iron losses = No load test,
Copper losses = Short circuit test
Regulation = (Impedance voltage/Rated input voltage)*100
Impedance voltage = Short circuit test(Voltage drop)
 
Is This Answer Correct ?    39 Yes 23 No
S.ravi
 
Answer
# 5
go for two tests
open and short circuits tests
From the open, u compute the core power loss and from the
short, u get copper losses. then the formula is
efficiency = output/ (output + the above two losses)
SIMPLE
 
Is This Answer Correct ?    14 Yes 11 No
Prof Dr Lehaz Kakakhel
 

 
 
 
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