Transformers - Study Mode

[#121] The value of flux involved m the e.m.f. equation of a transformer is
Correct Answer

(C) maximum value

Explanation

Solution: The value of flux involved in the e.m.f. equation of a transformer is Given by: E = 4.44 * f * N * Φmax where: E is the induced e.m.f. f is the frequency of the AC supply N is the number of turns in the coil Φmax is the maximum flux The e.m.f. equation of a transformer involves the maximum value of the magnetic flux (Φmax) because the equation is derived based on the peak value of the sinusoidal flux waveform. Therefore, the correct answer is Option C: maximum value.

[#122] In a given transformer for given applied voltage, losses which remain constant irrespective of load changes are
Correct Answer

(C) hysteresis and eddy current losses

[#123] The changes in volume of transformer cooling oil due to variation of atmospheric tem-perature during day and night is taken care of by which part of transformer
Correct Answer

(A) Conservator

[#124] Star/star transformers work satisfactorily when
Correct Answer

(B) load is balanced only

[#125] Delta/star transformer works satisfactorily when
Correct Answer

(C) on balanced as well as unbalanced loads