The structure of a DC motor should consist of two main parts: the stator and rotor. The stationary part of a DC motor during operation is called the stator. The main function of the stator is to generate a magnetic field, consisting of the frame, main magnetic pole, commutator pole, end cover, bearings, and brush device. The rotating part during operation is called the rotor, whose main function is to generate electromagnetic torque and induced electromotive force. It is the hub for energy conversion in a DC motor, so it is usually called an armature, consisting of a shaft, armature iron core, armature winding, commutator, and fan.

stator

(1) Main magnetic pole

The function of the main magnetic pole is to generate an air gap magnetic field. The main magnetic pole is composed of two parts: the main magnetic pole core and the excitation winding. The iron core is generally made of 0.5mm to 1.5mm thick silicon steel plates, laminated and riveted, divided into two parts: the pole body and the pole shoe. The part with the excitation winding on top is called the pole body, and the widened part below is called the pole shoe. The pole shoe is wider than the pole body, which can adjust the distribution of magnetic field in the air gap and fix the excitation winding. The excitation winding is wound with insulated copper wire and is sheathed on the core of the main magnetic pole. The entire main magnetic pole is fixed to the base with screws

(2) Commutation pole

The function of the commutation pole is to improve commutation and reduce the possible commutation sparks between the brush and the commutator during motor operation. It is generally installed between two adjacent main magnetic poles and consists of the commutation pole core and the commutation pole winding. The commutation pole winding is made of insulated wires and is sheathed on the commutation pole iron core. The number of commutation poles is equal to the main magnetic pole.

(3) Base

The outer shell of the motor stator is called the frame. The function of the base is twofold:

One is used to fix the main magnetic pole, commutation pole, and end cover, and to support and fix the entire motor;

The second is that the base itself is also a part of the magnetic circuit, which forms the magnetic path between the magnetic poles. The part through which the magnetic flux passes is called the magnetic yoke. To ensure that the base has sufficient mechanical strength and good magnetic conductivity, it is generally made of cast steel or welded from steel plates.

(4) Brush device

The brush device is used to introduce or introduce DC voltage and DC current. The brush device consists of a brush, a brush holder, a brush rod, and a brush rod holder. The brush is placed inside the brush holder and compressed with a spring to ensure good sliding contact between the brush and the commutator. The brush holder is fixed on the brush rod, which is installed on a circular brush rod seat and must be insulated from each other. The brush rod seat is installed on the end cover or bearing inner cover, and the circumferential position can be adjusted. After adjustment, it is fixed.

rotor

(1) Armature core

The armature core is the main part of the main magnetic circuit and is used to embed the armature winding. Generally, the armature iron core is made of 0.5mm thick silicon steel sheets and laminated to reduce eddy current and hysteresis losses generated in the armature iron core during motor operation. The stacked iron core is fixed on the shaft or rotor bracket. The outer circle of the iron core is equipped with an armature slot, in which the armature winding is embedded.

(2) Armature winding

The function of the armature winding is to generate electromagnetic torque and induced electromotive force, and it is a key component for energy conversion in DC motors, so it is called the armature. It is composed of many coils (hereinafter referred to as components) connected in a certain pattern, and the coils are wound with high-strength enameled wire or glass wire wrapped flat copper wire, with different wires