Bearing wear is indicated by which symptom?

• A. Unequal gap between armature and pole pieces
• B. Grooving
• C. Streaking
• D. Bar Edge Burning

Answer: (A)

Unequal air-gap around the circumference is the clearest sign of bearing wear. When bearings wear, the rotor can become misaligned or run eccentrically, so the gap between the armature and the pole pieces isn’t the same all the way around. That variation—larger in some spots and smaller in others—shows up as an unequal gap and is the most direct indication that the bearing condition is affecting the rotor alignment.

Other terms describe wear or symptoms that come from different problems: grooving is wear on bearing surfaces or journals from contact or insufficient lubrication, streaking is typically related to brush/commutator or lubrication issues, and bar edge burning points to overheating of stator bars rather than bearing-induced misalignment.