Direct current machines are energy transfer devices. These machines can function as either a motor or a generator. DC motors and generators have the same basic construction, differing primarily in the energy conversion. To better understand the operation and construction of DC machines, a few basic terms must be understood.

EO 1.4STATE the purpose of each of the following components of a DC machine:

a. Armature b. Rotor c. Stator d. Field

Armature

The purpose of the armature is to provide the energy conversion in a DC machine (refer to Figure 2).

In a DC generator, the armature is rotated by an external mechanical force, such as a steam turbine. This rotation induces a voltage and current flow in the armature. Thus, the armature converts mechanical energy to electrical energy.

In a DC motor, the armature receives voltage from an outside electrical source and converts electrical energy into mechanical energy in the form of torque.

Figure 2 Basic DC Machine