The carbon brush is most commonly used in the motors as compared to copper brushes or other fabric brushes. While titan brushes are useful for the cranes and forklifts, carbon brushes prove to be the best for motors. The advantages of carbon brush that makes it useful in the dc motors are listed below.
· High Melting Point
As compared to other metals, carbon has a high melting point. As the brushes in dc motors are closely linked to the commutator, an increase in temperature causes instability among other metals. But with carbon brushes, stability can be maintained even at high temperatures.
· Shape Adopting Nature
Even though the carbon brush is available in a rectangular shape, the brush comes with great elasticity. On being fixed near the commutator, the carbon brush can easily adopt the circular shape of the commutator.
· Soft Metal
As compared to copper, carbon proves to be a more soft metal. The soft nature of the carbon brush prevents the commutator from being damaged when friction is produced between the brush and the commutator. With the use of copper or other fabric brushes, there are high chances of damage to the commutator because of the hardness of the metal.
The self-lubricating ability of the carbon brushes makes it useful for the dc motors. It prevents the requirement of any other lubricating oil or grease for the cooling purpose. The carbon brushes automatically get cooled once the dc motor is turned off.
The negative temperature co-efficient is another reason to use the carbon brush in dc motors. With a negative temperature coefficient, the resistance gets reduced whenever there is an increase in temperature. Using the carbon brush in the dc motors reduces the chances of damage and offer protection from sparks.