The function of a DC motor armature

　　 Automotive Armature In the process of completing the mutual conversion of mechanical energy and electromagnetic energy in an electric motor, it is the component that plays an important and core role. For a generator set, this is the component that causes the induced electromotive force, such as the motor rotor in a DC motor, and the stator in a DC motor; for a motor, this is the component that causes the magnetic force, such as the motor rotor in a DC motor.

　　The armature is a component in the electric motor that is equipped with a coil, and the electromagnetic coil has relative movement to the electromagnetic field. In a generator set, an induced current is generated in the rotating electromagnetic coil, which generates electricity. However, in a motor, the energized coil is subjected to Ampere force in the magnetic field, and then rotates in the magnetic field.

　　 DC motors or related equipment can also be described in terms of either mechanical or electrical aspects. Although distinctly separate, these two sets of terminology are often used interchangeably or include a combination of mechanical and electrical terminology. This can cause confusion when using hybrid devices such as brushless DC motors, or when communicating between personnel accustomed to using different configurations of equipment.

　　In most generator sets, the field magnetic field is rotating and is part of the motor rotor, while the armature is stationary and is part of the motor stator. Motors and generator sets can be composed of a stationary armature and oscillating or rotating electromagnet, or a rotating armature and stationary magnetic field. The pole shoes of permanent magnets or electromagnets and the iron parts that move with the magnetic lines of force (especially if the latter serves as a switch or solenoid) can also be called armatures.

　　What causes the reduction in automotive armature reaction?

　　Because the automotive armature is wound with electromagnetic coils, every time the current flows in the electromagnetic coils, a magnetic field strength is generated in the automotive armature. This field is at an angle to the generator field, which is called the cross-magnetization of the automotive armature. The function of the automotive armature magnetic field is to distort the generator magnetic field and move the neutral plane. The neutral plane is the position where the automotive armature windings move perpendicular to the magnetic lines of force, which is why the axis located on this plane is called the magnetic neutral axis (MNA). This effect is called armature reaction and is proportional to the current flowing in the automotive armature coils.

　　The generator's carbon brushes must be located in the neutral plane; in other words, they must contact the part of the armature windings connected to the commutator that has no induced current. If the carbon brushes contact the commutator segments outside the neutral plane, it will cause a short circuit in the "energized" electromagnetic coils, resulting in arcing and power loss.

　　Without armature reaction, the magnetic neutral axis (MNA) will coincide with the geometric neutral axis (GNA). Armature reaction causes the neutral plane to shift along the direction of motion, so if the brushes are in the neutral plane when there is no armature current, they will not be in the neutral plane when armature current flows. For these reasons, it is desirable to incorporate a compensating system into the generator design. These are two main ways to overcome the effects of armature reaction. One method involves changing the brush position so that they are in the neutral plane when the generator is producing normal load current. In another method, interpoles are installed in the generator to counteract the effects of armature reaction.