NEIEP Generator Maintenance and Repair (440) Practice Test

Dust and dirt contaminating a bearing introduce abrasive particles between the rolling elements and races. Those particles grind the surfaces, score the raceways, and damage the lubricant film that normally keeps metal surfaces separated. Once the lubricant film is compromised, metal-to-metal contact grows, causing heat, surface fatigue, pitting, and eventual spalling or seizure. Keeping bearings clean and properly sealed with clean lubricant helps prevent this creeping wear. Other factors like overload, misalignment, or high speed can worsen wear when present, but contamination directly drives wear and premature failure most consistently.