The work of “reversing the electric field” of an electric motor is made by two parts: the switch and the brushes. They work together to cause the current to flow to the electromagnet and also to reverse the direction in which the electrons are flowing in a timely manner.
The switch contacts are attached to the electromagnet shaft so that they rotate together with it. The brushes are only two pieces of flexible metal or graphite.
The armature is an electromagnet with a thin wire wound around two or more poles of a metal core. It has one axis https://www.mrosupply.com/hydraulics-and-pneumatics/hose-reels/2518572_112wl-1-100_coxreels/ and the switch is connected to its axis. There are three different images of the same armor: frontal, lateral and in the direction of the axis. In the image in the direction of the axis, the coil was covered to leave the switch more prominent.
The commutator is simply a pair of plates attached to the shaft. These plates provide two connections for the electromagnet coil.
The final piece of any DC electric motor is the field magnet. The field magnet in this type of motor is formed by the housing, plus the two curved permanent magnets. An electromagnet is based on an electric motor.