Carbon brushes: relevance in different industries

The carbon brushes are fundamental parts of any electric motor, since they provide the electrical connection between the rotating part (rotor) and its coils, thus creating a magnetic field with its fixed counterpart (stator), so we set ourselves the task of understanding what they are, what are the types of carbon brushes and their importance in the industry.

What are carbon brushes?

They are fundamental parts in electric motors which make electrical contact with the rotating part (rotor). According to the different types of electric motors, brushes vary in size and shape as they are created according to the technical specifications and end use of the motor.

Types of brushes

These seven types of brushes, are made according to the technical data of the motor, to provide optimum performance.

1. Spring-loaded: used on small motors, they are easily installed and uninstalled because they are held in place by a screw cap.
2. Cable: they have from one to four wires, are installed in carbon holders and are pressed against the commutator by means of a clamp.
3. Bipartite: they are composed of two or more carbon pads and can be of one wire, two wires or multiplex (several pads).
4. Riveted: the rivet is in the front part and can be of one wire, two wires, bipartite of one or two wires.
5. Dumbbell type: has a carbon at each end of the cable and can be single cable, two cable, riveted or double dumbbell.
6. Rheostat: it has the carbon, a spring and a metallic body that serves as carbon holder.
7. For lathe: or also known as spark plug type, it is used in conventional lathes.

Now that we know the types of brushes, it is important to highlight the characteristics of graphite that allow the correct operation of an electric motor. Among the qualities of graphite, we can highlight the following:

• Excellent electrical conductivity
• Self-lubrication
• Abrasion resistance
• Durability
• Handling during sliding contact

\Handling during sliding contact

Why are they important for different industries?

\Why are they important for different industries?

Due to the large number of electric motors of different types, sizes and applications, the characteristics of this fundamental part in any electric motor play an important role.

Electric motors are used for an endless number of applications in different industries such as the automotive, textile, food and mechanical industries in general.

In this way there are motors of greater or lesser power, speed and torque among other characteristics. Because of this, carbon/graphite brushes are used according to the application. Among these parameters are their electrical conductivity, hardness and low coefficient of thermal expansion, which provide a long, low-maintenance free life for electric motors.

Therefore, we can conclude that carbon/graphite brushes are indispensable in everyday life and must ensure the proper functioning of machines and tools of all kinds. The quality of the brush will depend on the needs of each machinery and industry.

In ESGRAF we have a wide inventory of graphite grades. Ask for a quote now!

Limitations to consider

Performance depends on graphite grade, grain orientation, temperature, load, pressure, speed, and operating environment. Material selection should be confirmed for your actual process conditions.

Information needed for a quote

To guide selection or prepare a quote, ESGRAF typically needs:

• Application and operating conditions (temperature, atmosphere, load).
• Dimensions, technical drawing, or CAD file when applicable.
• Required quantity.
• Requested grade or material currently in use.
• Observed issue with the previous part or lubricant, if any.

Request a quote

Share these details with our team at ESGRAF or request information. A specialist will review your application before recommending a grade or geometry.