Which statement about seating brushes is correct?

Which statement about seating brushes is correct?

• A. Emery paper should be used
• B. Emery paper should not be used
• C. Brushes should be heated
• D. Seating is optional

Answer: (B)

Seating carbon brushes is about creating a proper, uniform contact surface between the brush and the commutator so current flows smoothly and wear is even. The surface needs to be clean and smooth, not gouged or gritty. Using emery paper is not appropriate because it is abrasive and can leave grit on the commutator or embed particles in the brush surface. That grit and roughness lead to uneven contact, increased arcing, and accelerated wear, which defeats the purpose of seating. The correct approach is to seat by carefully bringing the brushes into contact and allowing them to burnish against the commutator during normal operation at low speed, with light pressure, so the surfaces mate properly. If cleaning is needed, use a clean, lint-free cloth and manufacturer-approved methods—not abrasive grit. Heating the brushes is not a recommended seating method, and seating is not optional—proper seating ensures reliable, low-arcing operation.

Seating carbon brushes is about creating a proper, uniform contact surface between the brush and the commutator so current flows smoothly and wear is even. The surface needs to be clean and smooth, not gouged or gritty. Using emery paper is not appropriate because it is abrasive and can leave grit on the commutator or embed particles in the brush surface. That grit and roughness lead to uneven contact, increased arcing, and accelerated wear, which defeats the purpose of seating.

The correct approach is to seat by carefully bringing the brushes into contact and allowing them to burnish against the commutator during normal operation at low speed, with light pressure, so the surfaces mate properly. If cleaning is needed, use a clean, lint-free cloth and manufacturer-approved methods—not abrasive grit. Heating the brushes is not a recommended seating method, and seating is not optional—proper seating ensures reliable, low-arcing operation.