STUPIDSID
Attempt any Four questions
1(a)
What are the advantages of auto transformer over two winding transformer.
5 M
1(b)
How the losses can be minimise in case of single phase transformer?
5 M
1(c)
What is Electromechanical Energy Conversion?
5 M
1(d)
Which speed control methods are used to get the speed above normal and below normal in case of DC Motor?
5 M
1(e)
List the advantages of Hopkinson's test.
5 M
2(a)
Derive the expression for torque developed in singly excited system.
10 M
2(b)
5 kVA, 200 / 400 V, 50 Hz single phase transformer gave following test result.
O.C. Test : 200 V, 0.9 A, 60 W (L. V. Side)
S.C. Test : 10 V, 6 A, 22 W (H. V. Silde)
Calculate :
(i) Efficiency and voltage regulative at full load 0.8.
(ii) Efficiency at 25 load at unity p.f.
O.C. Test : 200 V, 0.9 A, 60 W (L. V. Side)
S.C. Test : 10 V, 6 A, 22 W (H. V. Silde)
Calculate :
(i) Efficiency and voltage regulative at full load 0.8.
(ii) Efficiency at 25 load at unity p.f.
10 M
3(a)
Explain the different electrical braking methods for separately excited DC Motor.
10 M
3(b)
Two single phase transformer with equal voltage ratio having impedance of (0.819 + j 2.503) Ω and (0.8 + j 2.31) Ω with respect to secondary. If they operated in parallel how they will share the load of 3000 kw at p.f. 0.9 lagging?
10 M
4
A conductor of 4 m length moves under a magnetic field of flux density of 1.3 wb/m2 with velocity of 1.3 m/s calculate the magnitude of induced e.m.f. if conductor moves
(i) An angle of 50° to direction of field and
(ii) At 90° to axis of field.
(i) An angle of 50° to direction of field and
(ii) At 90° to axis of field.
20 M
5(a)
Explain communication in DC machine also explain the various methods of the improvement.
10 M
5(b)
Explain the characteristics of DC series and shunt motors.
10 M
6(a)
Draw and explain four point starter.
10 M
6(b)
Derive the expression for calculation demagnetising ampere turns per pole and cross mahnetisly ampere turns per pole
10 M
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