Two transformers are connected in parallel. These transformers do not have equal percentage impedance. This is likely to result in____________?
(A) short-circuiting of the secondaries
(B) power factor of one of the transformers is leading while that of the other lagging
(C) transformers having higher copper losses will have negligible core losses
(D) loading of the transformers not in proportion to their kVA ratings
During short circuit test iron losses are negligible because of _____________?
(A) the current on secondary side is negligible
(B) the voltage on secondary side does not vary
(C) the voltage applied on primary side is low
(D) full-load current is not supplied to the transformer
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
Power transformers are generally designed to have maximum efficiency around__________?
(A) no-load
(B) half-load
(C) near full-load
(D) 10% overload
Which winding of the transformer has less cross-sectional area?
(A) Primary winding
(B) Secondary winding
(C) Low voltage winding
(D) High voltage winding
Silicon steel used in lamination’s mainly reduces___________?
(A) hysteresis loss
(B) eddy current losses
(C) copper losses
(D) all of the above
Delta/star transformer works satisfactorily when______________?
(A) load is balanced only
(B) load is unbalanced only
(C) on balanced as well as unbalanced loads
(D) none of the above
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
Which of the following property is not necessarily desirable in the material for transformer core ?
(A) Mechanical strength
(B) Low hysteresis loss
(C) High thermal conductivity
(D) High permeability
Noise level test in a transformer is a______________?
(A) special test
(B) routine test
(C) type test
(D) none of the above