What material is commonly used for brushes on DC motors?

The common use of carbon for brushes on DC motors is primarily due to its excellent conductivity and ability to withstand high temperatures without significant wear. Carbon brushes provide a good balance of durability and electrical conductivity, allowing them to efficiently transfer electricity while minimizing the friction and heat generated during operation.

The properties of carbon allow for smoother operation and a longer lifespan compared to other materials. Its self-lubricating qualities help reduce maintenance needs, thus making it an ideal choice in the design and functioning of DC motors. Additionally, carbon brushes have a good resistance to sparking and are suitable for various environmental conditions, further contributing to their widespread use in electrical applications.

While other materials like copper and steel can conduct electricity, they do not offer the same level of performance and wear resistance in the context of rotary motion within motors. Silicon is not typically used for brushes in this application, as it is more commonly associated with semiconductor devices.