FEB 2018
ELECTRICIAN
THEORY
SEMESTER-4
PART-1
1. If a
slot consists of one coil
side then
the winding is called-
a) Double layer winding
a) Double layer winding
b) Full
pitch winding
c) Single
layer winding
d) Short
pitch winding
Answer:- b) Full pitch winding
2. A
capacitor start, capacitor run
single
phase induction motor is
basically
a
a) AC
series motor
b) DC
series motor
c) 2
phase induction motor
d) 3
phase induction motor
Answer:- c) 2 phase induction
motor
3. The
starting torque of a capacitor
start
motor is -
a) Zero
a) Zero
b)Low
c) Same
as rated torque
d) More
than rated torque
Answer:- b)Low
4. The
starling capacitor of a single phase motor is - .
a) Electrolytic capacitor
a) Electrolytic capacitor
b)
Ceramic capacitor
c) Paper
capacitor
d) None of
the above.
Answer:- a) Electrolytic capacitor
5. The
motor used in household
refrigerators
is -
a) DG series motor
a) DG series motor
b) DC
shunt motor
c)
Universal motor
d) Single
phase induction
motor.
Answer:- d) Single phase
induction motor
6. A
capacitor start single phase
induction
motor will usually
have a
power factor of
a) Unity
a) Unity
b) 0.8
leading
c)0.6
leading
d) 0.6
lagging
Answer:- d) 0.6 lagging
7. The
short coming of repulsion
motor is
-
a) Variation of speed with load
a) Variation of speed with load
b) Low
power factor
c)
Tendency to spark at brushes
d) All of
these
Answer:- d) All of these
8. A
ceiling fan of 1400 mm sweep
will have
motor rating of
a) 10 to 15 waits
a) 10 to 15 waits
b) 50 to
70 watts
c) 120 to
180 watts
b) 250 to
500 watts.
Answer:- c) 120 to 180 watts
9. Which
of the following
applications
would need the
smallest
size of motor?
a) Domestic motor
a) Domestic motor
b)
Electric clock
c) Table
fan
d) Sewing
machine
Answer:- b) Electric clock
10. Which
of the following is
not a
bio-mass source?
a) Gobar
gas
b) Coal
c) Wood
d)
Nuclear energy
Answer:- d) Nuclear energy
11. The source of energy of
the sun
is__
a)
Nuclear fission
b)
Chemical reaction
c).
Nuclear fusion
d)
Photoelectric effect
Answer:-c). Nuclear fusion
12. Which motor would you
select
for vacuum cleaners?
a) Universal motor .
a) Universal motor .
b)
Repulsion motor
c)
Hysteresis motor
d)
Reluctance motor.
Answer:- a) Universal motor
13. The advantage of*salient
poles in
an alternator is -
a) Reduce
noise
b)
Reduced windage loss
c)
Adoptability to low and
medium speed operation
d) Reduce
bearing loads
and noise.
Answer:- c) Adoptability to low
and
medium speed operation
14. Major share of power
generated
in India is through
which
means-
a) Hydroelectric power plants
a) Hydroelectric power plants
b)
Nuclear power plants
c)
Thermal power plants
d) Gas
turbine power plants
Answer:- ) Thermal power plants
15. A three phase alternator has
a phase
sequence of RYB for is
three output
voltages for
clockwise rotation. Now if the
clockwise rotation. Now if the
alternator
is rotated anticlockwise,
the phase
sequence will be
a) RYB
b) RBY
c) BYR
d) None
of these
Answer:- b) RBY
16. In an
alternator, voltage
drops
occurs in -
a)
Armature resistance only
b)
Armature resistance and
leakage reactance
c)
Armature resistance, leakage
reactance and armature reaction
d)
Armature resistance, leakage
reactance,
armature reaction and earth
Answer:- c) Armature resistance,
leakage reactance and armature
reaction
17. The
power Factor of an alternator
depends
on -
a) Load
b) Speed of rotor
c) Core
losses
d)
Armature losses
Answer:- a) Load
18. The frequency of voltage
generated
by. an alternator having
8 poles
and rotating at 250 rpm is
a) 60 Hz
b)50Hz
c)25Hz
c)25Hz
d) 16 2/3
Hz
Answer:- d) 16 2/3 Hz
19. A
winding is having number of
slots is
greater than number of polos,
then this winding is
called-
called-
a)
Concentrated winding
b)
Distributed winding
c) Full
pitch winding
d)
Integrated slot winding
Answer:- b) Distributed winding
20.
Synchronous motor can
operate
at -
a)
Lagging power factor only
b)
Leading power factor only
c) Unity
power factor only
d)
Lagging, leading and unity
power factor only
Answer:- d) Lagging, leading
and unity
power factor only
21. The
damping winding in a
synchronous
motor is generally used
a) To
provide starting torque only
b) To
reduce noise level
c) To
reduce eddy currents
d) To
prevent hunting and provide
the
starting torque
Answer:- d) To prevent hunting and
provide
the starting torque
22. The
back emf set up in ihe stator
of a
synchronous motor will depend on
a) Rotor
speed only
b) Rotor
excitation only
c) Rotor
excitation and rotor speed
d)
Coupling angle, rotor speed and
Answer:- b) Rotor excitation only
23. In a
synchronous motor, damper
winding
is provided to -
a)
Stabilize rotor motion
b)
Suppress rotor oscillations
c)
Develop necessary starting torque
d) Both
(a) & (c)
Answer:- d) Both (a) & (c)
24. Advantage of 'hydro-electric
power
station is
-
a) Low
operating cost
b) Free
from pollution problems
c) No
fuel transportation problems
d) All of
these
Answer:- d) All of these
25. An
Auto-transformer (which has
only one
winding) may be used as a
a) Step-Up Transformer
a) Step-Up Transformer
b)
Step-Down Transformer
c) Both
(a) & (b)
d) None
of the above
Answer:- c) Both (a) & (b)
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