Carbon Brush in the role of the motor:
1. Add the external current ( excitation current ) to the rotating rotor through the carbon brush ( input current )
2. Bring the electrostatic charge on the big shaft to the earth through the carbon brush ( grounded carbon brush ) ( output current )
3. Lead the large shaft ( ground ) to the protection device for rotor ground protection and measure the rotor positive and negative voltage to ground
4. Change the current direction ( in the commutator motor, the brush also plays a commutation function )
In addition to induction AC asynchronous motor there is no outside. All other motors are available as long as the rotor has a commutating ring.
The principle of power generation is that after a magnetic field cuts a wire, it generates current in the wire. The generator cuts the wire by rotating the magnetic field. The rotating magnetic field is the rotor, and the wire that is cut is the stator.
In order for the rotor to generate a magnetic field, it is necessary to input a magnetizing current to the coil of the rotor. The carbon brush is used to send the magnetoelectric current produced by the Li-magnetic generator into the rotor coil.
Only carbon brushes exist in the commutator or slip ring motor. The common AC asynchronous motor is a squirrel cage structure with no carbon brushes. The motor is the abbreviation for the motor, which is the motor. The motor can be divided into a DC motor and an AC motor. Since the rotor of the DC motor needs to change the direction of the current according to the position of the coil in the constant magnetic field, the DC motor coil needs a commutator.
The commutator consists of a brush and a commutating ring. A carbon brush is a type of brush. Because of the rotation of the rotor, the brush always rubs against the commutating ring, and at the moment of commutation, spark erosion occurs, so the brush is a wearing part in the DC motor.
In order to improve the service life and operation stability of DC motors and reduce noise and electromagnetic interference of DC motors, brushless DC motors have gradually replaced brush motors.
In general, AC motors do not use a constant magnetic field, so they do not need a commutator, and no brushes are required. However, AC motors are generally large in size. Electric motors used in household appliances are generally AC motors, such as electric fans, washing machines, refrigerators, air conditioners, etc. There are no carbon brushes, but there are also used DC motors, such as many electric shavers, kitchen appliances, electric bicycles, etc. have carbon The brush, which is a DC motor (not including brushless ones), has. The motors that use dry batteries are DC motors.
There are two types of AC asynchronous motors: In general, the factory uses a relatively large starting load, and the wound-type asynchronous motor has a slip ring for electricity (carbon) brush. (such as lifting, rolling mill motors, etc.), and the squirrel-cage induction motor with light-load start does not have a slip ring and therefore does not use electricity (carbon) brushes (such as fans, washing machines, air conditioners, refrigerators, etc.). DC motors have commutators, so they use electricity (carbon) brushes. The hand drill is generally a DC motor and the table drill is an AC asynchronous induction motor. Although the toy and the electric shaver are DC motors, the structure is simple and the cost is reduced. The phosphor containing elastic brass is used. The sheet is used to replace the electric (carbon) brush reversing device and is a wearing part of the electric shaver (the cord inside the motor is generally not damaged).
Type of carbon brush
People categorized numerous brushes for ease of use and management. At present, the main classification methods popular at home and abroad are:
1. Soft and hard materials can be divided into soft brushes, medium hard brushes and hard brushes.
2. According to the use of the brush objects can be divided into a brush for turbine generators, rolling brush motor useful brush, traction motor brush, brush for automotive tractors, brushes for power tools, aircraft motor power.
3. According to the brush color is divided into black brush ( made of pure carbon graphite material ) and colored brush ( made of copper and other metal materials and graphite ) .
The motor is a motor, a motor, a motor, a DC motor, and an AC motor.
Electric tool brush
Car and motorcycle brush
Industrial carbon brush
Generator carbon brush
DC generators, motors, and some alternators use carbon brushes. The current is conducted on the rotating member and the fixed member. Generator carbon brush and motor motor carbon brush is mainly metal graphite carbon brush, in which the generator brush is relatively black, mainly carbon; starter motor carbon brush has high copper content and the color is yellow compared to the color.
Features of carbon brush for motor
The role of the carbon brush is mainly to conduct metal friction while conducting; it is not the same as metal to metal friction conductive; metal to metal friction conductive; friction may increase; while the transfer of the place may be sintered together; Carbon brushes do not; because carbon and metal are two different elements; its use is mostly used in electric motors; shapes are varied; square ones are round and so on...
Carbon brushes are suitable for all types of motors, generators and axle machines. Has good commutation performance and long service life. The carbon brush is used for the commutator or slip ring of the motor. As a sliding contact body for the introduction and introduction of current, it has good electrical conductivity, thermal conductivity and lubricating performance, and has certain mechanical strength and commutation spark instinct. Almost all motors use carbon brushes, which are an important part of the motor. Widely used in a variety of AC and DC generators, synchronous motors, battery DC motor, crane motor collector ring, various types of welding and so on. With the development of science and technology, the types of motors and working conditions used are becoming more and more diversified. Therefore, brushes of various grades are required to meet these requirements, so the types of brushes also follow the development of the motor industry. more and more.
When installing a generator carbon brush, what problems should be noted?
When installing the engine carbon brush, note that:
1. The lead wire of the carbon brush is covered with insulating tube, and it should be installed in the insulating carbon brush holder. The lead wire is bare copper wire and it should be installed in the iron-plated carbon brush holder.
2. When the carbon brush is mounted on the carbon brush holder, the direction of the curved surface should be taken into consideration. If the mounting surface is too small, the contact surface will be too small to generate electricity or generate electricity.
3. The carbon brush should be able to freely rise and fall within the brush holder. If there is a card issue, the excess part should be ground off.
4. The carbon brush spring should be pressed in the middle of the carbon brush to prevent uneven grinding due to uneven force.
5. The contact area between carbon brush and commutator should not be less than 3/4 of the total contact surface , carbon brush must not have oil pollution