Transformers free Model online Quiz Test2

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1. The use of higher flux density in the transformer design _____.
reduces weight per kVA	reduces iron losses
reduces copper losses	increases part load efficiency

2. The chemical used in breather for transformer should have the quality of _____.
ionizing air	absorbing moisture
cleansing the transformer oil	cooling the transformer oil

3. The chemical used in breather is ______.
asbestos fibre	silica sand
sodium chloride	silica gel

4. The transformer ratings are usually expressed in terms of _____.
volts	amperes
kW	kVA

5. The noise resulting from vibrations of laminations set by magnetic forces, is termed as _____.
magnetostrication	boo
hum	zoom

6. Hysteresis loss in a transformer varies as CBmax = maximum flux density)
Bmax	Bmax1-6
Bmax1-83	B max

7. Material used for construction of transformer core is usually _____.
wood	copper
aluminium	silicon steel

8. The thickness of laminations used in a transformer is usually _____.
0.4 mm to 0.5 mm	4 mm to 5 mm
14 mm to 15 mm	25 mm to 40 mm

9. The function of conservator in a transformer is _____.
to project against'internal fault	to reduce copper as well as core losses
to cool the transformer oil	to take care of the expansion and contraction of transformer oil due to variation of temperature of sur-roundings

10. The highest voltage for transmitting electrical power in India is _____.
33 kV	66 kV
132 kV	400 kV

11. In a transformer the resistance between its primary and secondary is _____.
zero	1 ohm
1000 ohms	infinite

12. A transformer oil must be free from _____.
sludge	odour
gases	moisture

13. A Buchholz relay can be installed on _____.
auto-transformers	air-cooled transformers
welding transformers	oil cooled transformers

14. Gas is usually not liberated due to dissociation of transformer oil unless the oil temperature exceeds
50°C	80°C
100°C	150°C

15. The main reason for generation of harmonics in a transformer could be _____.
fluctuating load	poor insulation
mechanical vibrations	saturation of core

16. Distribution transformers are generally designed for maximum efficiency around _____.
90% load	zero load
25% load	50% load

17. Which of the following property is not necessarily desirable in the material for transformer core ?
Mechanical strength	Low hysteresis loss
High thermal conductivity	High permeability

18. Star/star transformers work satisfactorily when _____.
load is unbalanced only	load is balanced only
on balanced as well as unbalanced loads	none of the above

19. Delta/star transformer works satisfactorily when _____.
load is balanced only	load is unbalanced only
on balanced as well as unbalanced loads	none of the above

20. Buchholz's relay gives warning and protection against _____.
electrical fault inside the transformer itself	electrical fault outside the transformer in outgoing feeder
for both outside and inside faults	none of the above