Question

While conducting OCC, in order to avoid hysteresis loop, in which direction If should be increased?

(a) -ve direction

(b) +ve direction

(c) In any direction

(d) In both direction there exists hysteresis loop

I have been asked this question in homework.

I'd like to ask this question from No Load with On Load Characteristics of DC Generator in division DC Generator of DC Machines

Answer 1

Right answer is (b) +ve direction

For explanation I would say: In conducting the OCC test, If must be raised gradually only in the forward direction otherwise the curve would exhibit local hysteresis loops. In OCC at If =0 there exists small residual voltage shown by non-zero Voc.