The purpose of the rotor is to provide the rotating element in a DC machine (refer to Figure 2). In a DC generator, the rotor is the component that is rotated by an external force. In a DC motor, the rotor is the component that turns a piece of equipment. In both types of DC machines, the rotor is the armature.

Stator

The stator is the part of a motor or generator that is stationary (refer to Figure 2). In DC machines, the purpose of the stator is to provide the magnetic field. The stator in Figure 2 is provided by a permanent magnet.

Field

The purpose of the field in a DC machine is to provide a magnetic field for producing either a voltage (generator) or a torque (motor) (refer to Figure 2). The field in a DC machine is produced by either a permanent magnet or an electromagnet. Normally, electromagnets are used because they have an increased magnetic strength, and the magnetic strength is more easily varied using external devices. In Figure 2, the field is provided by the stator.

Summary

The construction of DC equipment is summarized below.

DC Equipment Construction Summary

The purpose of the armature is to provide the energy conversion in a DC machine.

The purpose of the rotor is to provide the rotating element in a DC machine.

In DC machines, the purpose of the stator is to provide the field.

The purpose of the field in a DC machine is to provide a magnetic field for producing either a voltage or a torque.

DC GENERATOR THEORY

DC generators are widely used to produce a DC voltage. The amount of voltage produced depends on a variety of factors.

EO 1.5

LIST the three conditions necessary to induce a voltage into a conductor.

EO 1.6

Using the left-hand rule of generators, DETERMINE the direction of the magnetic field, the motion of the conductor, or the direction of current induced into a conductor.

EO 1.7

DESCRIBE how terminal voltage of a DC generator is adjusted.

EO 1.8

STATE the basis behind each of the four DC generator ratings.

EO 1.9

LIST the four internal losses found in a DC generator.