Practice Test: Question Set - 14
1. If a transformer is switched on to a voltage more than the rated voltage
- (A) Its power factor will deteriorate
- (B) Its power factor will increase
- (C) Its power factor will remain unaffected
- (D) Its power factor will be zero
2. The no-load current drawn by transformer is usually what per cent of the full-load current?
- (A) 0.2 to 0.5 percent
- (B) 2 to 5 percent
- (C) 12 to 15 percent
- (D) 20 to 30 percent
3. A transformer transforms
- (A) Voltage
- (B) Current
- (C) Power
- (D) Frequency
4. Spacers are provided between adjacent coils
- (A) To provide free passage to the cooling oil
- (B) To insulate the coils from each other
- (C) Both (A) and (B)
- (D) None of the above
5. The highest voltage for transmitting electrical power in India is
- (A) 33 kV
- (B) 66 kV
- (C) 132 kV
- (D) 400 kV
6. Silicon steel used in laminations mainly reduces
- (A) Hysteresis loss
- (B) Eddy current losses
- (C) Copper losses
- (D) All of the above
7. Open circuit test on transformers is conducted to determine
- (A) Hysteresis losses
- (B) Copper losses
- (C) Core losses
- (D) Eddy current losses
8. The secondary of a current transformer is always short-circuited under operating conditions because it
- (A) Avoids core saturation and high voltage
induction
- (B) Is safe to human beings
- (C) Protects the primary circuit
- (D) None of the above
9. The maximum load that a power transformer can carry is limited by its
- (A) Temperature rise
- (B) Dielectric strength of oil
- (C) Voltage ratio
- (D) Copper loss
10. Buchholz's relay gives warning and protection against
- (A) Electrical fault inside the transformer
itself
- (B) Electrical fault outside the transformer in
outgoing feeder
- (C) For both outside and inside faults
- (D) None of the above
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