In the context of vibration analysis, what does the presence of sidebands adjacent to a peak indicate?

The presence of sidebands adjacent to a peak in vibration analysis typically indicates a potential fault in the system. Sidebands occur when there are modulations in the vibration signal, often due to the interaction of fault frequencies, such as when a fault manifests itself in terms of amplitude or frequency shift. They are particularly noticeable in cases of faults like roller element bearing defects or misalignment, where the condition of the components causes variations in the amplitude of vibration at the fundamental frequency.

In contrast, normal operation would not typically exhibit these sidebands, as it signifies a stable and consistent vibration response without perturbations caused by faults. A strong resonant condition may present a peak, but it does not inherently mean the presence of sidebands, which specifically point towards dynamic changes in the system indicative of emerging issues. Lastly, excessive torque on the bearings might cause vibration but would not necessarily lead to the formation of sidebands in the same manner as a fault would.