Order normalization helps in comparing spectra when there are changes in what factor?

Order normalization is a technique used in vibration analysis that allows for the comparison of vibration spectra under varying operational conditions, specifically when the speed of the motors or equipment changes. This process involves the conversion of the frequency spectra into a dimensionless form that is related to the rotational speed of the equipment, typically expressed in orders of rotation.

When motor speeds vary, the frequencies of interest in the vibration spectrum will also shift. For example, at higher speeds, the fundamental frequencies of vibration become higher, which can lead to difficulties when trying to compare data taken at different speeds. By normalizing the order, analysts can express the vibration data in terms of multiples of the rotational speed, enabling a straightforward comparison irrespective of the absolute speed differences. This standardized approach helps in identifying potential issues related to the machinery’s health accurately.

The other factors listed, such as measurement tools, environmental conditions, and frequency ranges, do not directly relate to the process of normalizing orders in the context of motor speed changes. While they are important in evaluating the overall vibration analysis, they do not specifically pertain to the adjustment of spectral comparisons needed due to variations in motor speeds.