Conservator
Breather
Bushings
Buchholz relay
Answer is Right!
Answer is Wrong!
Transformers
22. The magnetising current of a transformer is usually small because it has
small air gap
large leakage flux
laminated silicon steel core
fewer rotating parts
Answer is Right!
Answer is Wrong!
Detailed SolutionThe magnetising current of a transformer is usually small because it has
23. Power transformers are generally designed to have maximum efficiency around
no-load
half-load
near full-load
10% overload
Answer is Right!
Answer is Wrong!
Detailed SolutionPower transformers are generally designed to have maximum efficiency around
24. Efficiency of a power transformer is of the order of
100 per cent
98 per cent
50 per cent
25 per cent
Answer is Right!
Answer is Wrong!
Detailed SolutionEfficiency of a power transformer is of the order of
25. Which winding in a transformer has more number of turns?
Low voltage winding
High voltage winding
Primary winding
Secondary winding
Answer is Right!
Answer is Wrong!
Detailed SolutionWhich winding in a transformer has more number of turns?
26. Which of the following properties is not necessarily desirable for the material for transformer core?
Low hysteresis loss
High permeability
High thermal conductivity
Adequate mechanical strength
Answer is Right!
Answer is Wrong!
27. Noise level test in a transformer is a
special test
routine test
type test
none of the above
Answer is Right!
Answer is Wrong!
28. In a transformer routine efficiency depends upon
supply frequency
load current
power factor of load
both (B) and (C)
Answer is Right!
Answer is Wrong!
Detailed SolutionIn a transformer routine efficiency depends upon
29. 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
Answer is Right!
Answer is Wrong!
Detailed SolutionStar/star transformers work satisfactorily when
30. When secondary of a current transformer is open-circuited its iron core will be
hot because of heavy iron losses taking place in it due to high flux density
hot because primary will carry heavy current
cool as there is no secondary current
none of above will happen
Answer is Right!
Answer is Wrong!
Detailed SolutionWhen secondary of a current transformer is open-circuited its iron core will be