Which of the following can low-frequency vibrations indicate?

Low-frequency vibrations can indeed suggest potential structural issues within a system. This is primarily because low-frequency vibrations are often produced by phenomena such as misalignment, imbalance, or other mechanical defects that can affect the integrity of structural components. When these low-frequency vibrations are detected, they may indicate that certain parts of the machinery are experiencing excessive stress or strain, leading to potential failure or damage if not addressed.

In contrast, while low-frequency vibrations could relate to system efficiency or normal machine operations, they are most critically associated with predicting structural concerns. Insulation breakdown typically manifests through different vibration patterns or electrical characteristics rather than solely low-frequency vibrations. Therefore, recognizing low-frequency vibrations as an indicator of potential structural issues is crucial for preventive maintenance and ensuring the reliability of the overall system.