What Are The Main Components Of DC Motor?

First, the stator.
The stator of the DC motor is the part that generates the motor magnetic field, which is composed of the frame, the main magnetic pole, the excitation winding and the commutator pole.
1. Machine base.
The base of the DC motor is not only the shell of the motor, but also used as a protection and support structure, and is also a part of the magnetic circuit of the motor (that is, the yoke part).
2. Main magnetic pole.
The function of the main magnetic pole is to generate a magnetic field, which is composed of the main magnetic pole iron core and the field winding.
The main magnetic pole core consists of a pole body and a pole shoe (also known as the pole palm) two parts, near the rotor side called the pole shoe, the pole shoe is generally wider than the pole body, so that the magnetic flux distribution below the pole is uniform. When the rotor rotates, the groove and teeth move relative to the magnetic pole, causing eddy current loss on the surface of the pole shoe. In order to reduce this eddy current loss, the magnetic pole core is usually made of 1 ~ 2mm thin steel plate after punching and pressing, and is riveted tightly. It is also made of 0.5mm thick silicon steel sheet laminated.
3, excitation winding.
The exciting winding is a concentrated winding, which is generally wound with copper or aluminum wire on the winding machine according to the model size, and then placed on an iron frame slightly larger than the main magnetic pole iron core, and the iron frame is then placed on the main magnetic pole iron core. There are mica insulating paper and epoxy glass fiber laminate between the winding and the iron frame as good insulation, and finally it is dipped in paint. The whole main magnetic pole is fixed on the frame with a screw, and when direct current is passed into the field winding, the main magnetic flux is generated in the motor.
4. Commutator pole.
In order to improve commutation, most DC motors are also equipped with commutation poles, also known as intermediate poles, between the main magnetic poles. The commutator pole has a large air gap on the rotor, so the vortex generated is small, so its iron core is mostly made of whole steel processing, and it is also used to stack steel sheets in large DC motors.
The winding of the commutator pole is generally in series with the armature winding, the current is larger, and the round copper wire or flat copper wire with a larger cross-section is generally wound, and the structure of the commutator pole is similar to the main magnetic pole.
Second, rotor (i.e. armature).
The rotor is composed of iron core, winding, commutator, rotating shaft and wind blade. Rotor is an important part of energy conversion.
1. Armature core.
The armature core is a cylinder with evenly distributed teeth and slots. In order to reduce hysteresis and eddy current losses, the armature core is generally made of 0.5mm thick silicon steel sheets that are insulated from each other.
2, armature winding.
The main function of armature winding is to generate induced potential and output or input current, so that the motor can realize energy conversion. The armature winding is usually made by winding the insulated copper wire on the online die into a coil and then embedded in the iron core slot. The two ends of each component of the winding are connected with the corresponding reversing plate respectively. In order to prevent the winding from flying out due to the centrifugal force when the armature rotates, the slot is sealed with a slot wedge. The end extending out of the groove is fastened to the winding support with epoxy phenolic weft less glass ribbon or steel wire.
3. Commutator.
The commutator plays the role of commutation, which is a cylinder made of many wedge-shaped commutator pieces (copper pieces) that are insulated from each other. There are many types of commutators, and there are two kinds of metal sleeve commutators and plastic sleeve commutators commonly used in small and medium-sized DC motors. Plastic sleeve commutators can save a lot of copper and mica, and simplify the processing process.
3. Other components.
1. Brush device.
The commutator is connected to the external circuit by a brush. The brush is installed in the brush holder, and the brush holder is fixed on the brush rod insulated with it, and the brush rod is installed on the brush rod seat. The brush rod seat can be moved around the axis, so that the position of the brush on the commutator can be adjusted. After the position of the brush is adjusted, the brush rod seat is fixed on the end cover (the brush rod seat of the large motor is fixed on the machine base), no longer change.
2. End cover.
Generally made of cast iron, there are two parts of the front end cover and the back end cover, and the back end cover is provided with an observation window to check the size of the spark of the brush. The end cap is usually used as a support and mounting bearing for the rotor, but the bearings of large motors are mounted on the bearing housing.