8/12/2019 DEA MODEL I
1/2
SRI CHANDRASEKHARENDRA SARASWATHI VISWA MAHAVIDYALAYA
(University Established Under Section III of the UGC Act,
1956)
DEPARTMENT OF ELECTRICAL AND ELECTRONICS ENGINEERING
MODEL QUESTION PAPER
Course & Branch: B.E Par! T"#e$ % EEE
Cre"!: '
Se#es!er: (I
Su)*ec! Coe: +., To!a- Mars: +/
DESIGN OF ELECTRICAL APPARATUS
Ans0er ALL !he Ques!"ons 1 2 3, 4 +/ Mars$
1. Explain the procedure for calculating leakage reactance in
transformer in detail. (12)
(Or)
2. Determine the apparent flux density in the teeth of a DC
Machine hen the real fluxdensity is 2.1! "#$m2% slot pitch 2&
mm% slot idth 1' mm and the gross core length of
'.! m. he num#er of *entilating ducts is +% each 1' mm ide. he
magneti,ing force
for a flux density of 2.1! "#$m2 is !!''' -$m. he iron stacking
factor is '.. (12)
. Deri*e the output e/uation of a DC machine. (12)
(Or)
+. Determine the diameter and length of armature core for a !!
k"% 11'0% 1''' rpm%+ poleshunt generator% assuming specific
electric and magnetic loadings of 2''' amp.cond. $
m and '.! "# $ m2respecti*ely. he pole arc should #e a#out '3 of
pole pitch andlength of core a#out 1.1 times the pole arc. -llo 1'
ampere for the field current and
assume a *oltage drop of + *olts for the armature circuit.
4pecify the inding to #e used
and also determine suita#le *alues for the num#er of armature
conductors and slots. (12)
!. Deri*e the output e/uation of 5.6 transformers. (12)
(Or)
. he tank of 12!' 70-% natural oil cooled transformer has the
dimensions length% idth
and height as '.! x 1.!! x 1.&! m respecti*ely. he full load
loss 8 1.1 7"% loss
dissipation due to radiations 8 " $ m259C% loss dissipation due
to con*ection 8.! " $
m29C% impro*ement in con*ection due to pro*ision of tu#es 8 +'3%
temperature rise 8+'9C% length of each tu#e 8 1m% diameter of tu#e
8 !'mm. :ind the num#er of tu#es for
this transformer. ;eglect the top and #ottom surface of the tank
as regards the cooling.
(12)
