Improper brush tension can cause both _______ and _______ wear.

Improper brush tension can cause both _______ and _______ wear.

• A. Thermal wear and chemical wear
• B. Magnetic wear and abrasive wear
• C. Electrical wear and mechanical wear
• D. Electrical wear and chemical wear

Answer: (C)

Brush tension determines how firmly the carbon brush presses against the commutator. If the tension isn’t correct, the contact quality changes, leading to two wear paths. When the tension is too loose, the brush may lose stable contact and current can arc across gaps, which erodes the brush and commutator surfaces—electrical wear. If the tension is too tight, there’s excessive friction and pressure, causing rapid mechanical rubbing and wear of both the brush and the commutator surfaces—mechanical wear. So improper brush tension leads to both electrical wear and mechanical wear.

Brush tension determines how firmly the carbon brush presses against the commutator. If the tension isn’t correct, the contact quality changes, leading to two wear paths. When the tension is too loose, the brush may lose stable contact and current can arc across gaps, which erodes the brush and commutator surfaces—electrical wear. If the tension is too tight, there’s excessive friction and pressure, causing rapid mechanical rubbing and wear of both the brush and the commutator surfaces—mechanical wear. So improper brush tension leads to both electrical wear and mechanical wear.