The analysis of rotating machinery is central to refinement activities in many fields including automotive, aerospace, power generation and general industry. It also enables engineers to trace faults in gearboxes, transmission systems and bearings. Every rotating part in a machine generates vibration and hence noise as a result of small imperfections in the balance or smoothness of the components of the machine. In addition there are so-called "blade-passing" phenomena associated with blades of fans and pumps. In every case the frequency of the vibration can be related to the speed of the rotating machine. These vibrations act as a forcing function on the structure of the machine or vehicle where they are mounted.

The most severe effects occur when the frequency of excitation generated by the rotating component matches one of the natural frequencies of the structure. These “coincidence” frequencies are often the target of considerable design effort to limit the effects, whether they be fatigue, vibration, or resulting noise. With variable speed machines, it is a considerable challenge to reduce noise and vibration to acceptable levels.

The Prosig Rotating Machinery Analysis Suite contains a complete set of tools for analyzing the sources of vibration and noise in the machine, and the resulting noise and vibration.

One of the main tools for rotating machinery analysis is classical waterfall analysis, producing frequency spectra related to the speed of rotation. These are produced by accelerating or decelerating the machine across a range of speeds. The software includes comprehensive tacho conditioning software so that a high quality speed signal can be produced. The waterfall can optionally be produced with a phase component relative to the tachometer. This can be useful in balancing applications. Waterfalls can also be averaged, which is useful when the runup or rundown is not consistent and there is external noise, which is unrelated to the rotation. The software allows many different visualizations of the waterfall, with hidden lines and sloped axes. It can also be shown as a spectrogram and as a Campbell diagram. Data can be displayed versus frequency or order and this is often useful in the investigation of coincident frequencies. Order cuts and frequency cuts can also be displayed. This gives the result of the analysis at a single order, frequency or speed.

Orders can be extracted as integer ratios, for the analysis of engines and motors, or at fractional orders, more useful for the analysis of gearboxes. Band-pass filtering and envelope analysis can be carried out for bearing analysis.