Browse  |   Placement Papers  |   Company  |   Code Snippets  |   Certifications  |   Visa Questions Post Question  |   Post Answer  |   My Panel  |   Search  |   Articles  |   Topics  |   ERRORS new
 Do you have a collection of Interview Questions and interested to share with us!! Please send that collection to along with your userid / name. ThanQ

 Categories >> Engineering >> Electrical Engineering

 Civil Engineering Interview Questions (2985) Mechanical Engineering Interview Questions (3261) Electrical Engineering Interview Questions (13159) Electronics Communications Interview Questions (2344) Chemical Engineering Interview Questions (407) Aeronautical Engineering Interview Questions (76) Bio Engineering Interview Questions (16) Metallurgy Interview Questions (79) Industrial Engineering Interview Questions (162) Instrumentation Interview Questions (2308) Automobile Engineering Interview Questions (104) Mechatronics Engineering Interview Questions (38) Marine Engineering Interview Questions (43) Power Plant Engineering Interview Questions (69) Engineering AllOther Interview Questions (1185)
Question
```What is the formula for calculating Transformer Losses &
Efficiency. I want to compare the Transformer efficiency at
Question Submitted By :: Piyush Rana
I also faced this Question!!     Rank Answer Posted By

Re: What is the formula for calculating Transformer Losses & Efficiency. I want to compare the Transformer efficiency at different loading condition.
# 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 ? 220 Yes 57 No
Kashifhabib
[Orient Energy Systems Pakistan]

Re: What is the formula for calculating Transformer Losses & Efficiency. I want to compare the Transformer efficiency at different loading condition.
# 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

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
=(0.5)^2 *400
=0.25*400

 Is This Answer Correct ? 113 Yes 49 No
Vinod Parasa

Re: What is the formula for calculating Transformer Losses & Efficiency. I want to compare the Transformer efficiency at different loading condition.
# 3
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 ? 38 Yes 19 No
S.ravi

Re: What is the formula for calculating Transformer Losses & Efficiency. I want to compare the Transformer efficiency at different loading condition.
# 4
POWER Transformer is 55MVA, 27/11.5KV ,efficiency =99.49

Find the Losses of Transformer

 Is This Answer Correct ? 33 Yes 13 No
N.makali

Re: What is the formula for calculating Transformer Losses & Efficiency. I want to compare the Transformer efficiency at different loading condition.
# 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 ? 13 Yes 9 No
Prof Dr Lehaz Kakakhel

  Question Asked @ Answers Other Electrical Engineering Interview Questions whats the necessary to correct the power factor using capacitive banks in industries? 2 conditions for parallel operation of dc generators 1 Can I parallel 1 MVA generator with 1kVA Generator? if V, F, Ph Seq and Ph angles are same 2 What is effect of low pf on HT supply. 6 The advantage of free wheeling diode in a Full Ware rectifier is -reduces the harmonics -Supplies the voltage at negative vlotage GNFC 3 what is the difference between arc and spark Jindal 2 How voltage step down is done? IOCL 3 A rotor of an induction machine is delta connected. Now is there any necessacity to short the slip rings? TCS 8 what is multiplying factor of a energy meter connected with a CT ratio of 600/5 and voltage at 415 volts. 1 What should be value of Circuit breaker operating time and tripping time? 5 I hv a question regarding power factor improvement just after transformer. I request you to reply me plzz. thank you sir. My friend has a small unit of fabrication. in his factory the main load is a welding machine, lathe machine, grinding machine. this load is not continuous type. now our electricity board has installed 16 KVA, 11000/433 V transformer for our factory. In the energy meter (trivector meter) at LV side of transformer, i hv seen power factor value of 0.15 only when only 3 KW load was flowing. Further electricity board has suggested to install 4 KVAR capacitor at LV side after energy meter. Now my question is that if we permanantly install and switch on 4 KVAR capacitor after energy meter, during some load on transformer and also without any load on transformer, wht will be the power factor shown in energy meter?i dont want to get any penalty by electricity board, so plz suggest me if i can permanantly install and switch on the 4 kvar capacitor or not at LV side of transformer just after energy meter? Thank you again and awaiting for ur positive reply soon. 8 what is entropy? NTPC 3 For more Electrical Engineering Interview Questions Click Here