The DC electric machine was for some time the most appropriate solution to problems in which it was essential to vary the speed during operation, and because of the simplicity to change the speed with this type of electric motor, which can be obtained by varying the continuous supply voltage or varying the intensity of the magnetic field. This has resulted in its widespread use in the past. In addition, in situations where only continuous power supplies were arranged, it was more feasible to use a DC machine than to convert DC to AC, using electric motors that are powered by an alternating current. skirtboard rubber
The DC machine has two main parts: the stator and the rotor. The stator and rotor are separated by the air gap. The stator is the part of the machine that is stationary, that is, has no movement. The rotor is the moving or rotating part. Both stator and rotor are built using ferromagnetic materials and it is necessary to increase the flow density and thereby decrease the size of the machine.