Certified Reliability Leader (CRL) Practice Test

What are common causes of vibration issues in motors?

1. Overheating and rust

2. Misalignment and out of balance

3. Loosely fitted parts

4. Electrical failures

The correct answer is: Misalignment and out of balance

Misalignment and being out of balance are significant contributors to vibration issues in motors. When components of a motor are not properly aligned, the rotational forces can create uneven stress, leading to increased vibration. This misalignment can stem from improper installation or wear over time. Similarly, when a motor is out of balance, it means that the mass distribution around the rotating shaft is not uniform, which causes oscillations as the motor runs. These conditions can lead to accelerated wear, reduced efficiency, and, ultimately, failure of the motor if not addressed. The other options, while they may have some impact on motor performance, do not directly address the specific mechanical issues that primarily cause vibrations. For instance, overheating and rust can lead to failure but do not inherently create vibration as misalignment and imbalance do. Loosely fitted parts can contribute to mechanical failure but are less specific in their relationship to vibration compared to alignment or balance issues. Electrical failures might affect a motor's operation or efficiency but do not generate physical vibration like misalignment or imbalance in the motor structure.