Most starter motors are series motors. They are called series motors because the rotating loop and
the windings around the magnetic poles are connected in one (series) path. The current flowing
through the loop also flows through the windings. In an actual motor, the windings around the
pole shoes are called field windings because they help produce the magnetic field. The purpose of
the field winding is to produce a strong magnetic field so that the loop will receive a more powerful
push. The poles are curved so the conductors of the loop can pass as close as possible to the poles
as they move past. Since the magnetic field is strongest near the poles, the conductors in the loops
are given a stronger push.
In an actual cranking motor, there are many rotating loops all assembled into an armature. The
armature consists of a shaft on which a laminated iron core and commutator are mounted. The
loops, or windings, of the armature are mounted in the core and are insulated from one another
and from the core. The commutator segments have riser bars, like the generator, to which the
ends of the armature windings are connected by soldering.