DC electric motors can be used as both motors and generators. However, the operation as a generator is limited, since the power rectifier sources generate continuous voltage in a controlled way, from the alternating network.
The development of alternating current (AC) drive techniques and the economic advantage have favored the replacement of DC motors with induction motors, which are driven by frequency inverters.
The DC motor is composed of two magnetic structures, the stator and the rotor Morse 321317 40NP O/L. The stator is composed of a ferromagnetic structure with poles where the coils are wound. The rotor is an electromagnet consisting of an iron core with windings on its surface formed by a switch.
The function of the switch is to invert the current in the rotation phase, so that the developed torque is always in the same direction. Switching consists of changing a switch blade, where the coils are connected in series and during that switching the coil is short circuited by the brushes. This helps to release the stored energy before the current flows in the opposite direction.