Transient Commutation Characteristics of Small-Sized DC Motor

Abstract

In the recent direct current (dc) motor whose speed is precisely controlled, it is necessary to maintain a good commutation characteristic in the transient state where the armature current changes abruptly. In this paper, the authors clarify theoretically and experimentally the relations between the transient behavior of the commutating flux in a commutating zone in the interpole airgap and the commutation characteristics, where the experiment is done by using a small-sized dc motor. Also, they experimentally confirm that the initial delay of the transient response of the commutating flux to the abrupt change of the armature current deteriorates the transient commutation characteristics, and that the deteriorated initial commutation characteristics are improved by intensifying the interpole exciting magnetomotive force. Furthermore, the authors suggest that it is necessary to analyse experimentally and theoretically in detail the transient behaviors of the magnetic fluxes in the commutating zone, the yoke and so on, which relate closely to the transient commutation characteristics.