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
The core used in high frequency transformer is usually___________?
A. copper core
B. cost iron core
C. air core
D. mild steel core
Hysteresis loss in a transformer varies as CBmax = maximum flux density) ?
A. Bmax
B. Bmax1-6
C. Bmax1-83
D. B max
The no-load current drawn by transformer is usually what per cent of the full-load current ?
A. 0.2 to 0.5 per cent
B. 2 to 5 per cent
C. 12 to 15 per cent
D. 20 to 30 per cent
When secondary of a current transformer is open-circuited its iron core will be__________?
A. hot because of heavy iron losses taking place in it due to high flux density
B. hot because primary will carry heavy current
C. cool as there is no secondary current
D. none of above will happen
Helical coils can be used on___________?
A. low voltage side of high kVA transformers
B. high frequency transformers
C. high voltage side of small capacity transformers
D. high voltage side of high kVA rating transformers
The dielectric strength of transformer oil is expected to be______________?
A. lkV
B. 33 kV
C. 100 kV
D. 330 kV