Armature-Reactions

When an armature is running in an active dynamo a series of reactions is established, the more important of which are: I. A tendency to cro -magnetize the armature. II. A tendency to spark at the brushes. III. A tendency for the armature current to demagnetize on account of the lead which has to be given to the brushes. IV. Variations in the neutral points as more or le current is taken from the machine. V. Heating of armature, both core and conductors, and of pole pieces, which heating is due to Foucault currents.