FAA Powerplant Written Practice Test

What are indentations on bearing races caused by high static loads called?

1. Waviness

2. Dimpling

3. Brinelling

4. Scoring

The correct answer is: Brinelling

Indentations on bearing races caused by high static loads are referred to as Brinelling. This phenomenon occurs when excessive pressure is applied to the bearing while it is stationary, leading to permanent deformation of the race surface. Brinelling is characterized by small, permanent indentations that can affect both the performance and lifespan of the bearing. Understanding Brinelling is crucial for maintenance and engineering practices, as it often indicates improper loading conditions or inadequate support of the bearing during operation. Identifying this issue early can prevent further damage and ensure the reliable performance of machinery relying on these bearings. Waviness pertains to surface irregularities resulting from manufacturing imperfections or wear, whereas dimpling specifically describes slightly recessed areas typically caused by vibration or impact under loaded conditions but not necessarily static loads. Scoring refers to scratches or grooves on the surface of the race caused by friction or contamination, rather than static load-related indentations.