Carbon brush, also known as electric brush, are widely used in electrical equipment. They are used to transmit signals or energy between the fixed part and the rotating part of some motors or generators.
The function of the carbon brush is to introduce the armature current required for motor operation into the armature coil through the connecting piece on the slip ring. The fit and smoothness of the carbon brush and the connecting piece, as well as the size of the contact surface, will affect its service life and reliability.
Practice has proved that the performance of the carbon brush is largely determined by the reliability of the motor operation. Then, what is the main function of carbon brushes in motors?
1. Control The Motor Speed
The carbon brush contacts the motor rotor and can transfer electrical energy to the motor rotor to form an electric current. At the same time, the carbon brush can control the current in the motor rotor, thereby controlling the motor's speed.
2. Change the direction of current
The carbon brush plays a key role in changing the direction of the current in the motor. As the rotor rotates, the brush and the commutation ring continue to rub, and spark erosion occurs at the moment of commutation. This friction and spark are inevitable processes of changing the direction of current in a DC motor.
3. Reduce plate wear
When the carbon brush comes into contact with the motor rotor, it can also form a protective film on the surface of the rotor to prevent polar plate wear and protect the life and use effect of the power tool.
4. Improve motor efficiency
The friction and contact of the carbon brushes will generate a certain amount of heat. Excessive friction and contact may cause premature wear of the carbon brushes and have a greater impact on the motor efficiency. Therefore, proper selection and maintenance of carbon brushes can improve motor efficiency and reduce usage costs.
5. Dust removal
Carbon brushes play a key role in dust removal. When the carbon brushes rub against the rotor, the static electricity generated can absorb dust and particles in the air, thereby achieving the dust removal effect.
