Functional characteristics of carbon brushes
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The main function of a carbon brush is to conduct electricity while rubbing against metal, unlike metal conducting electricity when rubbing against metal; When metal conducts electricity through friction with metal, the frictional force may increase, and the joints may be sintered together; Carbon brushes do not, because carbon and metal are two different elements. Most of its uses are in electric motors, with various shapes, such as square and round.
Carbon brushes are suitable for various motors, generators, and axle machines. It has good commutation performance and long service life. Carbon brushes are used on commutators or slip rings of electric motors as sliding contacts for deriving and introducing electric current. They have good electrical, thermal, and lubricating properties, as well as a certain mechanical strength and the instinct for commutative sparks. Almost all motors use carbon brushes, which are an important component of the motor. Widely used in various AC and DC generators, synchronous motors, battery DC motors, crane motor collector rings, various types of electric welding machines, and so on. With the development of science and technology, the types and operating conditions of motors are becoming increasingly diverse.
Specific role
1. Apply external current (excitation current) to the rotating rotor through a carbon brush (input current);
2. Introduce the static charge on the large shaft through the carbon brush to the ground (grounding carbon brush) (output current);
3. Lead the large shaft (ground) to the protection device for rotor ground protection and measurement of rotor positive and negative voltage to ground;
4. Change the direction of the current (in a commutator motor, the brush also plays a commutation role).
Except for induction AC asynchronous motors. Other motors are available, as long as the rotor has a commutation ring.
The principle of electricity generation is that after a magnetic field cuts a wire, an electric current is generated in the wire. Generators cut wires by rotating a magnetic field. The rotating magnetic field is the rotor, and the cut wire is the stator.