Why carbon brush is used in DC motor?

Carbon brushes are commonly used in DC motors because they are an effective and reliable method of transferring electrical current to the motor's rotating armature.

The carbon brush is a conductor that makes contact with the commutator, which is a segmented ring that is attached to the armature and rotates along with it. As the commutator segments make contact with the carbon brush, electrical current flows from the power source through the brush and into the armature, causing it to rotate.

Carbon brushes have several advantages as a method of current transfer in DC motors, including their durability, high conductivity, and ability to withstand high temperatures.

Carbon brush DC motors are also relatively easy to manufacture and maintain compared to other types of motors. However, carbon brushes do have some limitations, such as generating significant friction, requiring periodic replacement, and producing excess heat, which can impact motor performance in certain applications.

Overall, the use of carbon brushes in DC motors is a widely accepted and effective technique for transferring electrical current, and they remain a popular choice for many applications.