CRANKING MOTOR CONSTRUCTION
FIGURE 19. TYPICAL STARTING MOTOR.
The vehicle cranking motor has only one job to do, which is to turn the crankshaft at a speed fast
enough to start the engine. Since there are many different types and sizes of engines, there are
many types and sizes of cranking motors. The common starter motor used on military vehicles
consists of the following five main assemblies: armature, field and frame, commutator-end head,
drive-end housing, and drive mechanism. The field windings, frame, and armature are almost the
same as in the generator which you have already studied, except that in the starter motor the
windings are much heavier in order to carry a lot of current. The commutator-end head houses the
brush holders, brushes, and a bearing. The drive-end houses the drive mechanism and usually the
mounting flange to mount the starter to the engine.