Is it normal to observe harmonics of 1x in a vibration spectrum?

Observing harmonics of 1x (the fundamental frequency of the rotating machinery) in a vibration spectrum is expected and considered normal in vibration analysis. The fundamental frequency corresponds to the rotational speed of the machine, and the harmonics are multiples of this frequency. This presence of harmonics can arise due to various operational factors such as mechanical imbalances, misalignments, or even normal operational behavior in certain systems.

When analyzing vibration spectra, identifying the 1x frequency and its harmonics provides valuable insights into the machine's condition and performance. It allows practitioners to assess the operational integrity and helps in diagnosing issues by highlighting specific areas of concern, should amplitude levels be unusually high in these harmonics. The presence of these harmonics is generally an indication of the machine's functioning as designed, rather than a harbinger of problems unless they reach significant amplitude levels or are associated with specific anomalies.