A phenomenon observed in dynamo armatures. At full loads the hysteresis
decreases. The effect is thus expressed by S. P. Thompson. “When an
armature core is rotated in a strong magnetic field, the magnetization
of the iron is being continually carried through a cycle, but in a
manner quite different from that in which it is carried when the
magnetizing force is periodically reversed, as in the core of a
transformer. Mordey has found the losses by hysteresis to be somewhat
smaller in the former case than in the latter.”