Q.1
When secondary of a current transformer is open-circuited its iron core will be
Q.2
Which of the following does not change in an ordinary transformer?
Q.3
When a given transformer is run at its rated voltage but reduced frequency, its
Q.4
Which of the following does not change in a transformer?
Q.5
In the transformer following winding has got more cross-sectional area
Q.6
The transformer laminations are insulated from each other by
Q.7
Buchholz's relay gives warning and protection against
Q.8
The efficiency of two identical transformers under load conditions can be determined by
Q.9
For a transformer, operating at constant load current, maximum efficiency will occur at
Q.10
The core used in high frequency transformer is usually
Q.11
A transformer transforms
Q.12
The secondary winding of which of the following transformers is always kept closed?
Q.13
If a transformer is switched on to a voltage more than the rated voltage
Q.14
In case of a double cage induction motor, the inner cage has
Q.15
If the supply frequency to the transformer is increased, the iron loss will
Q.16
In a transformer the resistance between its primary and secondary should be
Q.17
Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds
Q.18
The value of flux involved m the e.m.f. equation of a transformer is
Q.19
In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are
Q.20
Helical coils can be used on
Q.21
In a transformer the resistance between its primary and secondary is
Q.22
A transformer can have regulation closer to zero
Q.23
Power transformers are designed to have maximum efficiency at
Q.24
The transformer oil should have _____ volatility and _____ viscosity.
Q.25
The degree of mechanical vibrations produced by the laminations of a transformer depends on
Q.26
The term 'cogging' is associated with
Q.27
For given applied voltage, with the increase in frequency of the applied voltage
Q.28
In an actual transformer the iron loss remains practically constant from noload to fullload because
Q.29
The changes in volume of transformer cooling oil due to variation of atmospheric tem-perature during day and night is taken care of by which part of transformer
Q.30
Star/star transformers work satisfactorily when
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