Top 350+ Solved Electrical Machine 1 MCQ Questions Answer
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 thetr
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 tr
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
Q. N atural air coo ling is generally restricted for transformers up to
a. 1.5 MVA
b. 5 MVA
c. 15 MVA
d. 50 MVA
Q. A shell-type transformer has
a. high eddy current losses
b. reduced magnetic leakage
c. negligibly hysteresis losses
d. none of the above