Hi friends, this post is about transformer objectives. These are some of the questions asked in previous question papers of Gate, IES and other competitive exams. check out and comment if you have any doubts.....
1) The flux in transformer core
A) increases with load
B) decreases with load
C) remains constant irrespective of load
D) none of the above
Ans:C
2) When a transformer is operating on no-load, the primary applied voltage is approximately balanced by
A) primary induced emf
B) secondary induced emf
C) terminal voltage across the secondary
D) voltage drop across the resistance and reactance
Ans:A
3) In a transformer, zero voltage regulation at full load is
A) not possible
B) possible at unity power factor load
C) possible at leading power factor load
D) possible at lagging power factor load
Ans:C
4) In a 3-phase, 5KV, 5MVA system, what is the base impedence?
A) 5 ohms
B) 50 ohms
C) 500 ohms
D) 0.5 ohms
Ans:A
5) In the transformer circuit mode, the core loss is represented as a
A) series resistance
B) series inductance
C) shunt resistance
D) shunt inductance
Ans:C
6) The inductive reactance of a transformer depends on
A) electromotive force
B) magnetomotive force
C) magnetic flux
D) leakage flux
Ans:D
7) Power transformed from primary to secondary depends up on
A) number of primary turns
B) number of secondary turns
C) current transformation ratio
D) magnetic coupling between primary and secondary windings
Ans:D
8) The phasor diagram of a transformer on load can be drawn only if we know
A) equivalent circuit parameters of the transformer
B) load current
C) load pf
D) all of the above
Ans:D
9) The mutual flux in a loaded transformer can be varied by varing
A) primary current
B) load impedance
C) secondary current
D) reluctance of the magnetic path
Ans:D
10) Full-load voltage regulation of a power transformer is zero when power factor of the load is near
A) unity and leading
B) zero and leading
C) zero and lagging
D) unity and lagging
Ans:A
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