Practice Test: Question Set - 15
1. The transformer laminations are insulated from each other by
- (A) Mica strip
- (B) Thin coat of varnish
- (C) Paper
- (D) Any of the above
2. Which of the following does not change in an ordinary transformer?
- (A) Frequency
- (B) Voltage
- (C) Current
- (D) Any of the above
3. In a transformer the tapings are generally provided on
- (A) Primary side
- (B) Secondary side
- (C) Low voltage side
- (D) High voltage side
4. The value of flux involved m the e.m.f. equation of a transformer is
- (A) Average value
- (B) r.m.s. value
- (C) Maximum value
- (D) Instantaneous value
5. The dielectric strength of transformer oil is expected to be
- (A) 1 kV
- (B) 33 kV
- (C) 100 kV
- (D) 330 kV
6. Transformer breaths in when
- (A) Load on it increases
- (B) Load on it decreases
- (C) Load remains constant
- (D) None of the above
7. Which of the following is not a part of transformer installation?
- (A) Conservator
- (B) Breather
- (C) Buchholz relay
- (D) Exciter
8. When secondary of a current transformer is open-circuited its iron core will be
- (A) Hot because of heavy iron losses taking
place in it due to high flux density
- (B) Hot because primary will carry heavy current
- (C) Cool as there is no secondary current
- (D) None of above will happen
9. Which of the following protection is normally not provided on small distribution transformers?
- (A) Over-fluxing protection
- (B) Buchholz relay
- (C) Over-current protection
- (D) All of the above
10. The hum in a transformer is mainly attributed to
- (A) Load changes
- (B) Oil in the transformer
- (C) Magnetostriction
- (D) Mechanical vibrations
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