By watching, feeling, and listening to machine vibration, we can sometimes roughly determine the severity of the vibration. We may observe that certain kinds of machine vibration appear 'rough', others 'noticeable', and yet others 'negligible'. We can also touch a vibrating bearing and feel that it is 'hot', or hear that it is 'noisy', and so conclude that something is wrong.

Describing machine vibration with these general terms is, however, imprecise and depends on the person making the assessment. What appears 'rough' to one person may appear acceptable to another. Verbal description is usually unreliable.

To accurately analyze a vibration problem it is necessary to describe the vibration in a consistent and reliable manner. Vibration analysts rely primarily on numerical descriptions, rather than on verbal descriptions, to analyze vibration accurately, and to communicate effectively.

The two most important numerical descriptors of machine vibration are amplitude and frequency.

Amplitude describes the severity of vibration, and frequency describes the oscillation rate of vibration (how frequently an object vibrates). Together, amplitude and frequency of vibration provide a basis for identifying the root cause of vibration.

Tip provided by Commtest.