Transformers

The efficiency of a transformer, under heavy loads, is comparatively low because_______________?

A. copper loss becomes high in proportion to the output
B. iron loss is increased considerably
C. voltage drop both in primary and secondary becomes large
D. secondary output is much less as compared to primary input

The maximum load that a power transformer can carry is limited by its________________?

A. temperature rise
B. dielectric strength of oil
C. voltage ratio
D. copper loss

The hum in a transformer is mainly attributed to______________?

A. load changes
B. oil in the transformer
C. magnetostriction
D. mechanical vibrations

A. poor insulation
B. Overload
C. loose connections
D. Core saturation

If a transformer is continuously operated the maximum temperature rise will occur in_______________?

A. core
B. windings
C. tank
D. any of the above

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

Which of the following loss in a transformer is zero even at full load ____________?

A. Core loss
B. Friction loss
C. Eddy current loss
D. Hysteresis loss

Negative voltage regulation is indicative that the load is___________?

A. capacitive only
B. inductive only
C. inductive or resistive
D. none of the above

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

If the supply frequency to the transformer is increased,”the iron loss will__________?

A. not change
B. decrease
C. increase
D. any of the above