The electric motor of direct current and the most traditional rotary converter of electric power, having reached the final constructive characteristics already in the last quarter of century XIX. The basic structure of a conventional DC machine has two physically diverse parts 3/4 hp motors that are associated with two very specific electrical circuitry.
The stator housing the inductor poles, the auxiliary poles and eventually the compensating windings and the rotor that accommodates the coils associated with the power conversion and the switch blades. The inductor poles which are so called because they induce voltages in the rotor coils, have the geometry of protruding poles and are surrounded by coils of the inductor field winding.
The auxiliary poles, much smaller physically than the main inductors, are fixed between them and, for this reason, called interpolates, are also surrounded by coils and have the main function of canceling out the magnetic flux that eventually appears in the interpolar region, due to the armature chain and, for this reason, are connected in series with the armature. The coils that make up the field winding, once driven by direct current, generate the inductive magnetic flux.