TRANSFORMER MCQS SET 27

TRANSFORMER MCQS SET 27

1. The highest voltage for transmitting electrical power in India is
(a) 33 kV.        (6) 66 kV           (c) 132 kV         (d) 400 kV
Ans: d
 

2. In a transformer the resistance between its primary and secondary is
(a) zero        (b) 1 ohm          (c) 1000 ohms            (d) infinite
Ans: d
 

3. A transformer oil must be free from
(a) sludge      (b) odour         (c) gases         (d) moisture
Ans: d
 

4. A Buchholz relay can be installed on
(a) auto-transformers           (b) air-cooled transformers
(c) welding transformers         (d) oil cooled transformers
Ans: d
 

5. Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds
(a) 50°C         (b) 80°C          (c) 100°C            (d) 150°C
Ans: d
 

6. The main reason for generation of harmonics in a transformer could be
(a) fluctuating load                (b) poor insulation
(c) mechanical vibrations            (d) saturation of core
Ans: d
7. Distribution transformers are generally designed for maximum efficiency around
(a) 90% load          (b) zero load          (c) 25% load       (d) 50% load 

Ans: d
 

8. Which of the following property is not necessarily desirable in the material for transformer core?
(a) Mechanical strength              (b) Low hysteresis loss
(c) High thermal conductivity        (d) High permeability
Ans: c
 

9. 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
Ans: b
 

10. Delta/star transformer works satisfactorily when
(a) load is balanced only           (b) load is unbalanced only
(c) on balanced as well as unbalanced loads
(d) none of the above
Ans: c