Final answer:
Excessive run-out in a rotor can be caused by mechanical issues such as unbalanced rotor, misalignment, and worn bearings.
Step-by-step explanation:
Excessive run-out in a rotor can have several causes, including mechanical issues and imbalances. One cause is an unbalanced rotor, where the weight distribution is not evenly distributed. This can lead to vibrations and wobbling, causing the rotor to deviate from its intended path.
Another cause of excessive run-out is misalignment, where the rotor is not properly aligned with the axis of rotation. This can lead to uneven contact between the rotor and its support, resulting in run-out.
Furthermore, worn or damaged bearings can cause excessive run-out in a rotor. If the bearings are not functioning properly, it can introduce play or deflection in the rotor, leading to run-out.