CS/B.Tech(PWE-Old)/SEM-4/EE-401/2012
2012
ELECTRICAL MACHINES
Time Allotted : 3 Hours Full Marks : 70
The figures in the margin indicate full marks.
Candidates are required to give their answers in their own words
as far as practicable.
GROUP – A
( Multiple Choice Type Questions )
1. Choose the correct alternatives for any ten of the following :
10x1 = 10
i) A commutator in a d.c. generator can convert
a) a.c. to d.c. b) d.c. to a.c.
c) pulsating to d.c. d) none of these.
ii) In Swinburne’s method for the determination of
efficiency of a d.c. machine
a) the no load losses are calculated and the copper
losses are measured
b) the no load losses are measured and the copper
losses are calculated
c) both the no load losses and the copper losses are
measured
d) none of these.
iii) Best electric drive for locomotive is
a) squirrel cage induction motor
b) d.c. shunt motor
c) synchronous motor
d) d.c. series motor.
iv) Why are the transformer core made up of laminated
sheet ?
a) To reduce eddy current loss
b) To reduce hysteresis loss
c) To reduce frequency
d) None of these.