Deemed University 2009 A.M.I.E.T.E Electronics

g. Nuclear power station is normally used for

(A) peak load. (B) base load.
(C) avg. load. (D) any load.

h. A distance relay measures

(A) Difference in voltage. (B) Difference in impedance.
(C) Difference in current. (D) Difference in phase.

i. The efficiency of an induction motor under blocked rotor test conditions is

(A) 0.00%. (B) 100%.
(C) 60%. (D) 94%.

j. Welding is not done directly from the supply mains as

(A) Its voltage is too high.
(B) It is impracticable to draw heavy currents directly from the supply mains.
(C) Its voltage remain fluctuating.
(D) None of the above.



ans any 5 ques. out of 8 ques..
every ques. carries 16 marks.


Q.2 a. elaborate the various losses in a transformer? State and prove the condition for maximum efficiency of a transformer. (8)

b. A 100 kVA, 1100/230 V, 50 Hz transformer has an HV winding resistance of 0.1 O and a leakage reactance of 0.4 O. The LV winding resistance of 0.006 O and a leakage reactance of 0.01 O. obtain the equivalent winding resistance, reactance and impedance referred to the HV and LV sides. (8)

Q.3 a. discuss in brief the followings:
(i) In what condition is an synchronous machine referred to as a synchronous condenser?
(ii) Why is synchronous machine non self starting? How can it be made self starting? (4+4)

b. A 440 V, 50 Hz, ?-connected synchronous generator has a direct axis reactance of 0.12 O/phase and a quadrature axis reactance of 0.075 O/phase the armature resistance being negligible. The generator is supplying 1000A at 0.8 lagging pf.

Earning:   Approval pending.