Transformer MCQ Quiz - Set 09 - ObjectiveBooks

Transformer MCQ Quiz - Set 09

Practice Test: Question Set - 09


1. Star/star transformers work satisfactorily when
    (A) Load is unbalanced only
    (B) Load is balanced only
    (C) On balanced as well as unbalanced loads
    (D) None of the above

2. Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in
    (A) Short-circuiting of the secondaries
    (B) Power factor of one of the transformers is leading while that of the other lagging
    (C) Transformers having higher copper losses will have negligible core losses
    (D) Loading of the transformers not in proportion to their kVA ratings

3. During open circuit test of a transformer
    (A) Primary is supplied rated voltage
    (B) Primary is supplied full-load current
    (C) Primary is supplied current at reduced voltage
    (D) Primary is supplied rated kVA

4. Reduction in core losses and increase in permeability are obtained with transformer employing
    (A) Core built-up of laminations of cold rolled grain oriented steel
    (B) Core built-up of laminations of hot rolled sheet
    (C) Either of the above
    (D) None of the above

5. To step 120 V ac up to 900 V ac, the turns ratio must be
    (A) 75
    (B) 750
    (C) 7.5
    (D) 0.13

6. Which of the following acts as a protection against high voltage surges due to lightning and switching?
    (A) Horn gaps
    (B) Thermal overload relays
    (C) Breather
    (D) Conservator

7. An open-circuit test on a transformer is conducted primarily to measure
    (A) Insulation resistance
    (B) Copper loss
    (C) Core loss
    (D) Total loss

8. A certain transformer has 400 turns in the primary winding and 2,000 turns in the secondary winding. The turns ratio is
    (A) 0.2
    (B) 0.4
    (C) 5
    (D) 25

9. Minimum voltage regulation occurs when the power factor of the load is
    (A) Unity
    (B) Lagging
    (C) Leading
    (D) Zero

10. In a transformer the energy is conveyed from primary to secondary
    (A) Through cooling coil
    (B) Through air
    (C) By the flux
    (D) None of the above

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