Top 80+ Solved Transformers MCQ Questions Answer
Q. An ideal transformer will have maximum efficiency at a load such that
a. copper loss = iron loss
b. copper loss < iron loss
c. copper loss > iron loss
d. none of the above
Q. 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
Q. Negative voltage regulation is indicative that the load is
a. capacitive only
b. inductive only
c. inductive or resistive
d. none of the above
Q. 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
Q. 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
Q. The transformer laminations are insulated from each other by
a. mica strip
b. thin coat of varnish
c. paper
d. any of the above
Q. Which type of winding is used in 3phase shell-type transformer ?
a. Circular type
b. Sandwich type
c. Cylindrical type
d. Rectangular type
Q. During open circuit test of a transformer
a. primary is supplied rated voltage
b. primary is supplied full-load current
c. primary is supplied current at reduced voltage
d. primary is supplied rated kVA
Q. Open circuit test on transformers is conducted to determine
a. hysteresis losses
b. copper losses
c. core losses
d. eddy current losses
Q. Short circuit test on transformers is conducted to determine
a. hysteresis losses
b. copper losses
c. core losses
d. eddy current losses
Q. For the parallel operation of single phase transformers it is necessary that they shouldhave
a. same efficiency
b. same polarity
c. same kVA rating
d. same number of turns on the secondary side.
Q. The transformer oil should have _____ volatility and _____ viscosity.
a. low,low
b. high,high
c. low,high
d. high,low
Q. The function of breather in a transformer is
a. to provide oxygen inside the tank
b. to cool the coils during reduced load
c. to cool the transformer oil
d. to arrest flow of moisture when outside air enters the transformer
Q. 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
Q. The size of a transformer core will depend on
a. frequency
b. area of the core
c. flux density of the core material
d. (a) and (b) both