The secondary of a current transformer is always short-circuited under operating conditions because it A) avoids core saturation and high v...

For a transformer, operating at constant load current, maximum efficiency will occur at A) 0.8 leading power factor B) 0.8 lagging power f...

Which of the following protection is normally not provided on small distribution transformers ? A) Overfluxing protection B) Buchholz rela...

Which of the following acts as a protection against high voltage surges due to lightning and switching ? A) Horn gaps B) Thermal overload ...

The noise produced by a transformer is termed as A) zoom B) humming C) ringing D) buzz Show Answer Ans: B) humming "Show An...

Which of the following is the most likely source of harmonics in a transformer? A) poor insulation B) Overload C) loose connections D) C...

If a transformer is continuously operated the maximum temperature rise will occur in A) core B) windings C) tank D) Any of the above S...

The hum in a transformer is mainly attributed to A) load changes B) oil in the transformer C) magnetostriction D) mechanical vibrations ...

The maximum load that a power transformer can carry is limited by its A) temperature rise B) dielectric strength of oil C) copper loss D...

Part of the transformer which is most subject to damage from overheating is A) iron core B) copper winding C) winding insulation D) fram...

If supply frequency of a transformer increases, the secondary output voltage of the transformer A) remains same B) increases. C) decrease...

In transformer minimum voltage regulation occurs when the power factor of the load is A) unity B) lagging C) leading D) zero Show Answ...

In a step-down transformer, there is a change of 15 A in the load current. This results in change of supply current of A) less than 15 A B...

The efficiencies of transformers compared with that of electric motors of the same power are A) about the same B) much smaller C) much hi...

Which of the following loss in a transformer is zero even at full load ? A) Hysteresis loss B) Eddy current loss C) Core loss D) Frictio...

The efficiency of two identical transformers under load conditions can be determined by A) Back-to-Back test B) Short circuit test C) Ope...

The secondary winding of which of the following transformers is always kept closed ? A) Current transformer B) Potential transformer C) A...

Which type of winding is used in 3phase shell-type transformer ? A) Cylindrical type B) Circular type C) Sandwich type D) None of Above ...

If the supply frequency to the transformer is increased, the iron loss will A) remain same B) decrease C) increase D) None of Above Sh...

In a transformer the resistance between its primary and secondary is A) 0.1 ohm B) infinite C) 1 ohm D) 1000 ohm Show Answer Ans: B...