The secondary winding of which of the following transformers is always kept closed?
A. Step-up transformer
B. Step-down transformer
C. Potential transformer
D. Current transformer
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
Which of the following is the main advantage of an auto-transformer over a two winding transformer?
A. Hysteresis losses are reduced
B. Saving in winding material
C. Copper losses are negligible
D. Eddy losses are totally eliminated
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
A transformer core is laminated to__________?
A. reduce hysteresis loss
B. reduce eddy current losses
C. reduce copper losses
D. reduce all above losses
A. primary side
B. secondary side
C. low voltage side
D. high voltage side
The transformer oil should have _______ volatility and _______ viscosity?
A. low,low
B. high,high
C. low,high
D. high,low