🔍 Key Concepts

• Commutator wear patterns in DC generators • Effect of mechanical alignment vs electrical loading on commutator wear • Role of brush position and geometry in current distribution on the commutator

💭 Think About

• Which of these choices would cause the current to be carried more by some segments and less by others, leading to localized heating and wear? • Which options describe mainly electrical/load conditions, and which describe a physical/geometry issue that would affect all speeds and loads? • Think about how brushes actually sit on the commutator: what change would make the contact pressure or contact area different from segment to segment?

✅ Before You Answer

• Identify which options change the mechanical geometry of the magnetic field or brushes rather than just the load size • Ask: which condition would produce a repeating pattern of heavier arcing on certain segments, not randomly all around? • Eliminate any options that would more likely cause overall sparking or temperature rise rather than clearly uneven wear on particular parts of the commutator