Interpoles are additional poles which are placed between the main
poles in a dc machines. These poles are designed to counteract the
effects of armature reaction in the dc machines.

Interpoles are placed at the geometric mean axis. They are wound byconductors which are connected in series to the main armature winding.

The polarity of the interpoles is the same of the next approaching pole.

The chief function of the interpoles is to compensate the reactanceemf and to minimize sparking across the brushes.