Transformers Electrical Engineering Quiz Questions - Set 13 - ObjectiveBooks

Transformers Electrical Engineering Quiz Questions - Set 13

Practice Test: Question Set - 13

1. When a given transformer is run at its rated voltage but reduced frequency, its
    (A) Flux density remains unaffected
    (B) Iron losses are reduced
    (C) Core flux density is reduced
    (D) Core flux density is increased

2. A transformer can have regulation closer to zero
    (A) On full-load
    (B) On overload
    (C) On leading power factor
    (D) On zero power factor

3. The path of a magnetic flux in a transformer should have
    (A) High resistance
    (B) High reluctance
    (C) Low resistance
    (D) Low reluctance

4. The no load current in a transformer lags behind the applied voltage by an angle of about
    (A) 180°
    (B) 120°
    (C) 90°
    (D) 75°

5. The thickness of laminations used in a transformer is usually
    (A) 0.4 mm to 0.5 mm
    (B) 4 mm to 5 mm
    (C) 14 mm to 15 mm
    (D) 25 mm to 40 mm

6. The leakage flux in a transformer depends upon
    (A) Load current
    (B) Load current and voltage
    (C) Load current, voltage and frequency
    (D) Load current, voltage, frequency and power factor

7. Which winding of the transformer has less cross-sectional area?
    (A) Primary winding
    (B) Secondary winding
    (C) Low voltage winding
    (D) High voltage winding

8. The secondary winding of which of the following transformers is always kept closed?
    (A) Step-up transformer
    (B) Step-down transformer
    (C) Potential transformer
    (D) Current transformer

9. Which of the following is the most likely source of harmonics in a transformer?
    (A) Poor insulation
    (B) Overload
    (C) Loose connections
    (D) Core saturation

10. In a given transformer for a given applied voltage, losses which remain constant irrespective of load changes are
    (A) Hysteresis and eddy current losses
    (B) Friction and windage losses
    (C) Copper losses
    (D) None of the above

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