Top 350+ Solved Electrical Machine 1 MCQ Questions Answer
Q. Which of the following does not change in a transformer ?
a. Current
b. Voltage
c. Frequency
d. All of the above
Q. In a transformer the energy is conveyed from primary to secondary
a. through cooling coil
b. through air
c. by the flux
d. none of the above
Q. A transformer core is laminated to
a. reduce hysteresis loss
b. reduce eddy current losses
c. reduce copper losses
d. reduce all above losses
Q. The degree of mechanical vibrations produced by the laminations of a transformerdepends on
a. tightness of clamping
b. gauge of laminations
c. size of laminations
d. all of the above
Q. The no-load current drawn by transformer is usually what per cent of the full-loadcurrent ?
a. 0.2 to 0.5 per cent
b. 2 to 5 per cent
c. 12 to 15 per cent
d. 20 to 30 per cent
Q. The path of a magnetic flux in a transformer should have
a. high resistance
b. high reluctance
c. low resistance
d. low reluctance
Q. No-load on a transformer is carried out to determine
a. copper loss
b. magnetising current
c. magnetising current and loss
d. efficiency of the tr
Q. Sumpner's test is conducted on trans-formers to determine
a. temperature
b. stray losses
c. all-day efficiency
d. none of the above
Q. The permissible flux density in case of cold rolled grain oriented steel is around
a. 1.7 Wb/m2
b. 2.7 Wb/m2
c. 3.7 Wb/m2
d. 4.7 Wb/m2
Q. The efficiency of a transformer will be maximum when
a. copper losses = hysteresis losses
b. hysteresis losses = eddy current losses
c. eddy current losses = copper losses
d. copper losses = iron losses
Q. No-load current in a transformer
a. lags behind the voltage by about 75°
b. leads the voltage by about 75°
c. lags behind the voltage by about 15°
d. leads the voltage by about 15°
Q. The purpose of providing an iron core in a transformer is to
a. provide support to windings
b. reduce hysteresis loss
c. decrease the reluctance of the magnetic path
d. reduce eddy current losses
Q. Which of the following is not a part of transformer installation ?
a. Conservator
b. Breather
c. Buchholz relay
d. Exciter
Q. While conducting short-circuit test on a transformer the following side is shortcircuited
a. High voltage side
b. Low voltage side
c. Primary side
d. Secondary side