Electrical Machine - IES Academy
Electrical Machine - IES Academy
Electrical Machine - IES Academy
You also want an ePaper? Increase the reach of your titles
YUMPU automatically turns print PDFs into web optimized ePapers that Google loves.
India’s No. 1<br />
<strong>IES</strong> <strong>Academy</strong><br />
Transformer<br />
Chapter-1<br />
0.95 = 50× 1×<br />
1<br />
GATE-16. Ans. (c) η2wdg<br />
=<br />
50+w +w<br />
∴<br />
Cu<br />
i<br />
Cu<br />
w + w = 2.631<br />
i<br />
150<br />
For auto transformer, η = = 98.276%<br />
150 + 2.631<br />
GATE-17. Ans. (a)<br />
GATE-18. Ans. (d) KVA Rating = 25 × 400 = 1000 × 10 = 10000 KVA<br />
GATE-19. Ans. (d) p.u impedance = 0.02 + 0.07 j<br />
Base impedance referred to primary<br />
Z = Z ×Z = (0.02 + 0.07 j) (3630 Ω ) = (72.6 + j254.1)<br />
Ω<br />
GATE-20. Ans. (d)<br />
GATE-21. Ans. (c)<br />
(p.u)<br />
Base<br />
NBA<br />
Inductance = 1<br />
(proportional to A… cross section) when cross section<br />
becomes half, inductance becomes half.<br />
GATE-22. Ans. (d)<br />
GATE-23. Ans. (d)<br />
1<br />
GATE-24. Ans. (b) p.u leakage impedance α<br />
KVA<br />
∴ 500KVA × 0.05 = 250KVA × X<br />
GATE-25. Ans. (c)<br />
2<br />
<strong>IES</strong>-1. Ans. (b) P ∞V ⇒ P ( at 330V)<br />
e<br />
Previous Year <strong>IES</strong> Answer<br />
e<br />
2<br />
⎛330<br />
⎞<br />
= ⎜ × 50=112.5W<br />
220<br />
⎟<br />
⎝ ⎠<br />
<strong>IES</strong>-2. Ans. (b)<br />
<strong>IES</strong>-3. Ans. (d) Copper loss = (1/2) 2 × 6400 = 1600 W<br />
www.iesacademy.com E-mail: iesacademy@yahoo.com Page-50<br />
25, 1 st Floor, Jia Sarai, Near IIT. New Delhi-16 Ph: 011-26537570, 9810958290
Change language