DC motors are widely used to drive various equipment. The speed and torque produced in a DC motor depends on a variety of factors.

EO 1.1

Using the right-hand rule for motors, DETERMINE the direction of the magnetic field, direction of current flow, or force on a conductor.

EO 1.2

STATE the function of torque in a direct current motor and how it is developed.

EO 1.3

DESCRIBE how Counterelectromotive Force (CEMF) is developed in a DC motor.

EO 1.4

DESCRIBE the relationship between field current and magnetic field size in a DC motor.

EO 1.5

STATE the function of the CEMF that is developed in a DC motor.

EO 1.6 EO 1.7

DESCRIBE how the speed of a DC motor is adjusted.

DESCRIBE the relationship between armature current and torque produced in a DC motor.

Inducing a Force on a Conductor

There are two conditions which are necessary to produce a force on a conductor.

The conductor must be carrying current.

The conductor must be within a magnetic field.

When these two conditions exist, a force will be applied to the conductor, which will attempt to move the conductor in a direction perpendicular to the magnetic field. This is the basic theory by which all DC motors operate.