What is the function of the commutator in a DC generator?

The function of the commutator in a DC generator is to convert the alternating current (AC) that is generated in the armature winding into direct current (DC) suitable for use in external circuits. In a DC generator, as the armature rotates within the magnetic field, it induces an alternating voltage due to electromagnetic induction. The commutator, which is connected to the armature, rectifies this alternating current by switching the connections of the winding to the external circuit at the appropriate moments in the rotation. This switching action ensures that the output current flows in one direction, making it direct current.

Understanding the role of the commutator is fundamental to recognizing how DC machines function. While other components and designs may influence voltage output or current regulation, the primary function of the commutator is its rectifying action that directly enables the creation of usable DC power from the AC induced in the generator's coils.