Alternator brushes are primarily constructed from which material?

The correct answer is that alternator brushes are primarily constructed from carbon. Carbon is preferred for brush material because it possesses excellent electrical conductivity while also providing good wear resistance. This combination minimizes the amount of friction and heat generated at the contact point between the brush and the rotor, allowing for efficient electrical transfer in the alternator.

Carbon brushes are designed to maintain their shape and performance over time, ensuring reliable operation of the alternator by effectively transferring electrical current. Additionally, carbon has self-lubricating properties, which help reduce wear and extend the service life of the brushes.

Using other materials like copper or aluminum would not be as effective; while they are conductive, they would wear down more quickly and generate higher levels of heat, which could lead to premature failure of the alternator components. Similarly, using silver-copper alloys, while conductive, would increase costs significantly without providing enhanced performance over carbon. Thus, carbon’s unique properties make it the ideal material for alternator brushes.