Automotive Electrical and Electronic Systems Classroom Manual Fifth Edition Update by John F. Kershaw

Starting System Operation 193
Figure 9-26.
Brush end and end housing.
Figure 9-24.
Starter motor housing.
Figure 9-27.
Pole shoes and field windings in housing.
Figure 9-25.
The motor frame is a path for flux lines.
One end of the housing holds one of the two
bearings or bushings in which the armature shaft
turns. On most motors, it also contains the
brushes that conduct current to the armature
(Figure 9-26). This is called the brush, or commutator,
end housing. The other end housing
holds the second bearing or bushing in which the
armature shaft turns. It also encloses the gear
that meshes with the engine flywheel. This is
called the drive end housing. The drive end
housing often provides the engine-to-motor
mounting points. These end pieces may be made
of aluminum because they do not have to conduct
magnetic flux.
The magnetic field of the starter motor is
provided by two or more pole shoes and field
windings. The pole shoes are made of iron and
are attached to the frame with large screws
(Figure 9-27). Figure 9-28 shows the paths of
magnetic flux lines within a four-pole motor.
The field windings are usually made of a heavy