What material are generator brushes primarily made of to resist friction?

Generator brushes are primarily made of carbon due to its excellent properties suited for electrical applications. Carbon has a low coefficient of friction, which means it can effectively reduce wear and tear while maintaining optimal conductivity. This is crucial in the operation of generators as the brushes make contact with the rotating armature or commutator, and the material must withstand the mechanical wear from friction while also efficiently transferring electrical current.

Additionally, carbon brushes can maintain good conductivity even at high temperatures, making them ideal for use in generators that often operate under varying conditions. The choice of carbon allows for durability and performance, ensuring reliable operation over extended periods. In contrast, the other materials listed, while they have their own uses, do not provide the same balance of conductivity and low friction necessary for generator brushes.