Structural Analysis of DC Motors

The structure of the DC motor should be composed of two parts: the stator and the rotor. The stationary part of the DC motor is called the stator. The main function of the stator is to generate a magnetic field. The part that rotates during operation is called the rotor. Its main function is to generate electromagnetic torque and induced electromotive force. It is the hub for the energy conversion of the DC motor, so it is usually called the armature. Constructor and fan, etc.

1. Stator
(1) Main magnetic pole
The role of the main pole is to generate an air gap magnetic field. The main magnetic pole is composed of the main magnetic pole iron core and the excitation winding. The iron core is generally made of 0.5mm~1.5mm thick silicon steel plate punching and riveting. It is divided into two parts: the pole body and the pole shoe. The upper part of the excitation winding is called the pole body, and the lower part is called the pole body. The pole shoe is wider than the pole body, which can not only adjust the distribution of the magnetic field in the air gap, but also facilitate fixing the excitation winding. The excitation winding is made of insulated copper wire and is sleeved on the core of the main magnetic pole. The entire main magnetic pole is fixed on the base with screws.

(2) Commutation pole
The function of the commutation pole of the DC motor is to improve the commutation and reduce the possible commutation sparks between the brush and the commutator when the motor is running. The commutating pole winding is composed of the commutating pole winding, which is made of insulated wire and is sleeved on the commutating pole iron core. The structure of the main magnetic pole The number of commutating poles is equal to that of the main magnetic pole.
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(3) Machine base
The casing of the motor stator is called the frame, and the frame has two functions:
One is to fix the main magnetic pole, the commutation pole and the end cover, and to support and fix the entire motor;
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Second, the base itself is also a part of the magnetic circuit, which constitutes the magnetic path between the magnetic poles, and the part through which the magnetic flux passes is called the yoke. In order to ensure that the machine base has sufficient mechanical strength and good magnetic permeability, it is generally made of steel castings or welded steel plates.
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(4) Brush device
The brush device is used to introduce or draw DC voltage and DC current. The brush device consists of a brush, a brush holder, a brush rod and a brush rod seat. The brush is placed in the brush holder and pressed by a spring, so that there is a good sliding contact between the brush and the commutator. The brush holder is fixed on the brush rod, and the brush rod is mounted on the circular brush rod seat. must be insulated. The brush rod seat is installed on the end cover or the bearing inner cover, the circumferential position can be adjusted, and it is fixed after adjustment.