Electromagnetic DC motor by stator poles, rotor (armature), commutator (commonly known as the commutator), brush, housings and bearings, and
Electromagnetic direct current motor stator poles (main magnetic pole) formed by core and excitation windings. According to the excitation (the old standard is called magnetizing) methods can be divided into separately excited DC motor, shunt DC motor, his excited DC motor and the DC motor. Due to different excitation modes, the stator poles of magnetic flux (produced by the excitation coil of the stator poles of power) the laws are different.
Of the series excitation direct-current motor excitation winding and rotor winding through the brushes and commutator series, and armature current of excitation current is proportional to the stator magnetic flux increases with the increase of excitation current, torque is proportional to the square of the armature current, speed increases with the torque or current and rapidly declining. Its rated torque starting torque up to 5 times more than short-time overload torque can be more than 4 times times the rated torque, speed change rate, high no-load speed (usually does not allow it to run under no load). Through the use of external resistors in series with series winding (or parallel), or the series winding connected in parallel then come to adjust speed.
