🔍 Key Concepts

• Commutator maintenance and what its surface should look like after proper cleaning • The difference between cleaning a commutator and using solvents or oils that might affect insulation or cause tracking • What tool is normally used to dress or true a commutator surface while the machine is at rest

💭 Think About

• Which option actually abrades and smooths the copper segments without leaving residue or liquid on the surface? • Which materials listed could leave an oily film or moisture that might lead to arcing or carbon tracking on the commutator? • Which choice is known as a specialized tool used specifically for dressing and resurfacing commutators and slip rings?

✅ Before You Answer

• Eliminate any option that involves oil or solvent that could leave a film on the commutator surface • Focus on the option that is a purpose‑made tool for commutators rather than a general cleaning rag or chemical • Remember that the goal is to maintain a smooth, dry, even surface on the commutator that promotes good brush contact and minimizes sparking