Material used for construction of transformer core is usually___________________?
Material used for construction of transformer core is usually___________________?
A. wood
B. copper
C. aluminium
D. silicon steel
Material used for construction of transformer core is usually___________________?
A. wood
B. copper
C. aluminium
D. silicon steel
A transformer can have regulation closer to zero___________?
A. on full-load
B. on overload
C. on leading power factor
D. on zero power factor
The efficiencies of transformers compared with that of electric motors of the same power are____________?
A. about the same
B. much smaller
C. much higher
D. somewhat smaller
E. none of the above
Which of the following statements regarding an idel single-phase transformer having a turn ratio of 1 : 2 and drawing a current of 10 A from 200 V A.C. supply is incorrect?
A. Its secondary current is 5 A
B. Its secondary voltage is 400 V
C. Its rating is 2 kVA
D. Its secondary current is 20 A
E. It is a step-up transformer
Transformer breaths in when_______________?
A. load on it increases
B. load on it decreases
C. load remains constant
D. none of the above
The permissible flux density in case of cold rolled grain oriented steel is around__________?
A. 1.7 Wb/m2
B. 2.7 Wb/m2
C. 3.7 Wb/m2
D. 4.7 Wb/m2
When a given transformer is run at its rated voltage but reduced frequency, its____________?
A. flux density remains unaffected
B. iron losses are reduced
C. core flux density is reduced
D. core flux density is increased