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Free download in PDF Transformers Electrical Engineering Multiple Choice Questions and Answers for competitive exams. These short objective type questions with answers are very important for Board exams as well as competitive exams. These short solved questions or quizzes are provided by Gkseries.
(1)
Which winding in a transformer has more number of turns ?
[A]
Low voltage winding
[B]
High voltage winding
[C]
Primary winding
[D]
Secondary winding
Answer: High voltage winding
(2)
Primary winding of a transformer
[A]
is always a low voltage winding
[B]
is always a high voltage winding
[C]
could either be a low voltage or high voltage winding
[D]
none of the above
Answer: could either be a low voltage or high voltage winding
(3)
A transformer cannot raise or lower the voltage of a D.C. supply because
[A]
there is no need to change the D.C. voltage
[B]
a D.C. circuit has more losses
[C]
Faraday’s laws of electromagnetic induction are not valid since the rate of change of flux is zero
[D]
none of the above
Answer: Faraday’s laws of electromagnetic induction are not valid since the rate of change of flux is zero
(4)
A transformer transforms
[A]
voltage
[B]
current
[C]
power
[D]
frequency
(5)
In the transformer following winding has got more cross-sectional area
[A]
Low voltage winding
[B]
High voltage winding
[C]
Primary winding
[D]
Secondary winding
Answer: Low voltage winding
(6)
While conducting short-circuit test on a transformer the following side is short circuited
[A]
High voltage side
[B]
Low voltage side
[C]
Primary side
[D]
Secondary side
(7)
Which of the following is not a part of transformer installation ?
[A]
Conservator
[B]
Breather
[C]
Buchholz relay
[D]
Exciter
(8)
The purpose of providing an iron core in a transformer is to
[A]
provide support to windings
[B]
reduce hysteresis loss
[C]
decrease the reluctance of the magnetic path
[D]
reduce eddy current losses
Answer: decrease the reluctance of the magnetic path
(9)
No-load current in a transformer
[A]
lags behind the voltage by about 75°
[B]
leads the voltage by about 75°
[C]
lags behind the voltage by about 15°
[D]
leads the voltage by about 15°
Answer: lags behind the voltage by about 75°
(10)
The efficiency of a transformer will be maximum when
[A]
copper losses = hysteresis losses
[B]
hysteresis losses = eddy current losses
[C]
eddy current losses = copper losses
[D]
copper losses = iron losses
Answer: copper losses = iron losses
(11)
The permissible flux density in case of cold rolled grain oriented steel is around
[A]
1.7 Wb/m2
[B]
2.7 Wb/m2
[C]
3.7 Wb/m2
[D]
4.7 Wb/m2
(12)
Sumpner’s test is conducted on trans-formers to determine
[A]
temperature
[B]
stray losses
[C]
all-day efficiency
[D]
none of the above
(13)
The dielectric strength of transformer oil is expected to be
[A]
lkV
[B]
33 kV
[C]
100 kV
[D]
330 kV
(14)
No-load on a transformer is carried out to determine
[A]
copper loss
[B]
magnetising current
[C]
magnetising current and loss
[D]
efficiency of the transformer
Answer: magnetising current and loss
(15)
The path of a magnetic flux in a transformer should have
[A]
high resistance
[B]
high reluctance
[C]
low resistance
[D]
low reluctance
(16)
The no-load current drawn by transformer is usually what per cent of the full-load current ?
[A]
0.2 to 0.5 per cent
[B]
2 to 5 per cent
[C]
12 to 15 per cent
[D]
20 to 30 per cent
(17)
The degree of mechanical vibrations produced by the laminations of a transformer depends on
[A]
tightness of clamping
[B]
gauge of laminations
[C]
size of laminations
[D]
all of the above
(18)
A transformer core is laminated to
[A]
reduce hysteresis loss
[B]
reduce eddy current losses
[C]
reduce copper losses
[D]
reduce all above losses
Answer: reduce eddy current losses
(19)
In a transformer the energy is conveyed from primary to secondary
[A]
through cooling coil
[B]
through air
[C]
by the flux
[D]
none of the above
(20)
Which of the following does not change in a transformer ?
[A]
Current
[B]
Voltage
[C]
Frequency
[D]
All of the above
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