A no-load test is performed on a transformer to determine_______________?
A. core loss
B. copper loss
C. efficiency
D. magnetising current
E. magnetising current and loss
Harmonics in transformer result in___________?
A. increased core losses
B. increased I2R losses
C. magnetic interference with communication circuits
D. all of the above
A transformer can have regulation closer to zero___________?
A. on full-load
B. on overload
C. on leading power factor
D. on zero power factor
What will happen if the transformers working in parallel are not connected with regard to polarity ?
A. The power factor of the two trans-formers will be different from the power factor of common load
B. Incorrect polarity will result in dead short circuit
C. The transformers will not load in proportion to their kVA ratings
D. none of the above
Which of the following parts of a transformer is visible from outside ?
A. Bushings
B. Core
C. Primary winding
D. Secondary winding
A. to provide coupling between primary and secondary
B. to increase the magnitude of mutual flux
C. to decrease the magnitude of mag-netizing current
D. to provide all above features
Which of the following is not a routine test on transformers ?
A. Core insulation voltage test
B. Impedance test
C. Radio interference test
D. Polarity test