During light load maintenance, which action could help reduce commutator threading?

• A. Increase load
• B. Improve brush seating
• C. Lubricate the bearings
• D. Increase cooling

Answer: (B)

Maintaining good brush-to-commutator contact is essential to prevent commutator threading. When brushes seat properly, they press evenly against the commutator, allowing current to transfer uniformly across the surface. This reduces arcing and the localized wear that can gouge the surface and create thread-like grooves, a risk that’s heightened under light-load conditions where the brushes may not be pressed firmly by springs alone. By improving brush seating, you ensure consistent contact across the entire brush face, minimize sparking, and promote even wear, which together reduce the formation of threading on the commutator. Increasing load doesn’t address the contact quality and can introduce other stresses; lubricating the bearings or increasing cooling helps with mechanical or thermal issues but doesn’t fix poor brush contact at the commutator.