Which material property describes carbon brushes?

Which material property describes carbon brushes?

• A. carbon brushes
• B. bearings
• C. stator laminations
• D. end bells

Answer: (A)

Carbon brushes are defined by their carbon-based composition. They’re typically made from carbon graphite because this material conducts electricity while being relatively soft and self-lubricating, which gives a stable electrical contact with a rotating commutator or slip ring and reduces wear and arcing. This combination of conductivity and low-friction wear is what characterizes carbon brushes. The other parts referenced—bearings, stator laminations, and end bells—are different components with different material needs, so the carbon-based description best fits the brushes themselves.

Carbon brushes are defined by their carbon-based composition. They’re typically made from carbon graphite because this material conducts electricity while being relatively soft and self-lubricating, which gives a stable electrical contact with a rotating commutator or slip ring and reduces wear and arcing. This combination of conductivity and low-friction wear is what characterizes carbon brushes. The other parts referenced—bearings, stator laminations, and end bells—are different components with different material needs, so the carbon-based description best fits the brushes themselves.