Centrifugal fans are one of the most versatile and widely used pieces of rotating mechanical equipment found today. Fans follow basic laws of performance. An understanding of these laws is useful in determining the effect of changes to the operating parameters and can cause operational problems (i.e., stall, surge, etc.). These basic laws apply to any type of fan or fan system. This article is intended to be a summary of common fan problems that vibration analysis can identify.

Centrifugal pumps are some of the most common machine types in use throughout all industry types. Centrifugal pumps have unique problems such as cavitation, flow pulsation, etc., due to the operational conditions to which they are subjected that are not common to other machine types. These problems (or faulty conditions) can then generate unique vibration spectra and time waveforms. This article is intended to be a summary of common pump problems that vibration analysis can detect and resolve.

An interesting case study shows how two seemingly unrelated problems (warped motor frame and notable bearing fault) were identified and corrected using vibration analysis and high frequency enveloping. The story begins with production personnel of a chemical company reporting hearing a new noise emanating from a pump/motor unit. Maintenance was dispatched to investigate the noise and repair if required. The maintenance staff requested vibration diagnostics to determine the source of the noise, evaluate health of the machine and develop a list of corrective actions, if required.