Computer Programming MCQs

5739 MCQs  (Page 545 of 574)

Iron loss of a transformer can be measured by____________?
A. Low power factor wattmeter
B. Unity power factor wattmeter
C. Frequency meter
D. Any type of wattmeter
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
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
In an actual transformer the iron loss remains practically constant from no load to full load because:____________?
A. Value of transformation ratio remains constant
B. Permeability of transformer core remains constant
C. Core flux remains practically constant
D. Primary voltage remains constant
An ideal transformer will have maximum efficiency at a load such that?
A. Copper loss = iron loss
B. Copper loss iron loss
D. None of the above
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
An ideal transformer is one which has_____________?
A. No losses and magnetic leakage
B. Interleaved primary and secondary windings
C. A common core for its primary and secondary windings
D. Core of stainless steel and winding of pure copper metal
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 winding of the transformer has less cross-sectional area?
A. Primary winding
B. Secondary winding
C. Low voltage winding
D. High voltage winding