adspace


what is the role of impedance in transformer?based on
secondary f.l.current(139 amps) and impedance(4.07) of
415/415v of 100 kva transformer. what is the primary
current?

Answer Posted / ma.amulraaj,b.e. mba.,

It is %impedance Voltage.In Transformer,%impedance Voltage plays significant role .Here 100KVA,11KV /415 V.


Full load current Sec .current= VA / 1.732x V (Sec.Voltage)


=(100x 1000 )/(1.732x415 ) =139 Amps, ok


Full load current Primary .current= VA / 1.732x V (Primary
Voltage)


=(100 x 1000)/(1.732 x 11000)
=5.25 Amps

Here ,the full load secondary current is 139 Amps,the rated secondary voltage is 415 V,we can do Short circuit test by applying secondary voltage 415 V,we cannot get the full load secondary current,due to impedance of Transformer.Then we have to raise the secondary voltage gradually, at particular voltage it delivered the full load secondary current,note down the voltage say 440V.From that voltage we have to find out % impedance.440 /11000 = 4% %Z=4.0 %.As this case %Z=4.07,ie. it is (4.07 x11000)/100 =447.7 V.It means This transformer may delivered a full load current at 447V.


This % Impedance may vary from Transformer to Transformer.

Is This Answer Correct ?    3 Yes 1 No



Post New Answer       View All Answers


Please Help Members By Posting Answers For Below Questions

I want single line diagram for AMF & DG syncronizing panel

7287


i m in need of current rating chart of heavy duty pvc/xlpe, cu/al cables. can somebody provide me? if yes, plz send me at ashish_patel111@yahoo.com

2093


Why squirrel cage motor can only use with low starting loads ?

2172


# 4 hi friends i m from electrical branch and seeking for tech. + apti. both papers of hpcl plz get it available as soon as possible my email id is sumit_lig189@yahoo.co.in

2083


please send me latest & previous years question papers for IOCL Technical level questions

1958


I am going to appear RRB Sr. Section Engineer Exam, Electrical. Can you send me previous year questions of RRB Electrical engineer. specially Section Engineer questions. my email id is likerahulworld@gmail.com

1901


I am apply the AAI. So i want electrical sample question paper in technical with answer my id is vijayjobsmart@gmail.com

2795


Draw the vector diagram and condition for the following: 1) Dyn1 2) Ynd0 3) YnYn0

3755


where can i get vijaya electricals limited in hyderabad interview auestions can u give me the website address plz

2228


I have 2500KVA transformer delta/star,13.8KV/380V provided with LV 4000A breaker. Already I have 2300KW motor feeder with a full load 90%. Is it possible to connect another 1600A from that breaker? If so how the calculation is done?

3883


please send the last 5 years {{{JUNIOR ENGINEER - ELECTICAL, ELECTRONICS RRB CHENNAI and secundrabad}}} TECHNICAL question papers TO MY EMAIL ID dinesh100701@gmail.com

2269


i want bhel placement paper for electrical if anybody having pl send to my id kavitha867@myway.com immediately

2067


Electrical Engineering

2161


HAI SENT HPCL APTITUDE QUESTION PAPER, MY EMAIL ID IS angus_eee04@rediffmail.com,angus_eee04@yahoo.com

2352


I NEED RRB SYLABUS FOR JE ELECTRICAL ,PLEASE SEND TO MY E- MAIL ID joo28_eee@yahoo.co.in

2930