Q.1
Auto-transformer makes effective saving on copper and copper losses, when its transformation ratio is
Q.2
Noise level test in a transformer is a
Q.3
The 'crawling' in an induction motor is caused by
Q.4
Natural air cooling is generally restricted for transformers up to
Q.5
Which of the following is the main advantage of an auto-transformer over a two winding transformer?
Q.6
Primary winding of a transformer
Q.7
The efficiencies of transformers compared with that of electric motors of the same power are
Q.8
Open circuit test on transformers is conducted to determine
Q.9
Which of the following statements regarding an idel single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect?
Q.10
Negative voltage regulation is indicative that the load is
Q.11
Which motor is preferred for use in mines where explosive gases exist?
Q.12
Which type of winding is used in 3phase shell-type transformer?
Q.13
The noise resulting from vibrations of laminations set by magnetic forces, is termed as
Q.14
The power transformer is a constant
Q.15
Sumpner's test is conducted on transformers to determine
Q.16
In a transformer routine efficiency depends upon
Q.17
No-load on a transformer is carried out to determine
Q.18
The maximum efficiency of a distribution transformer is
Q.19
Which of the following protection is normally not provided on small distribution transformers?
Q.20
The transformer ratings are usually expressed in terms of
Q.21
For the parallel operation of single phase transformers it is necessary that they should have
Q.22
The dielectric strength of transformer oil is expected to be
Q.23
A transformer oil must be free from
Q.24
Insertion of resistance in the rotcir of an induction motor to develop a given torque
Q.25
The efficiency of a transformer will be maximum when
Q.26
Losses which occur in rotating electric machines and do not occur in trans formers are
Q.27

A reflective load is a load as it appears to the source in the primary of a transformer.

  • True
  • False
Q.28

If the voltage is stepped up, the current is stepped down, and vice versa.

  • True
  • False
Q.29

A step-up transformer steps up power.

  • True
  • False
Q.30

A step-down transformer has a turns ratio less than 1.

  • True
  • False
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