National Instruments Order Analysis Toolset - Manual (Page 16)

© National Instruments Corporation 2-1 LabVIEW Order Analysis Toolset User Manual
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Order Analysis
This chapter gives brief descriptions of the need for order analysis, the
basic concepts of order analysis, the effect of rotational speed on order
identification, and the different order analysis methods.
Order Analysis Definition and Application
When it is impossible or undesirable to physically open up a system and
study it, you often can gain knowledge about the system by measuring and
analyzing signals associated with the system. For example, physicists and
chemists use the spectrum generated by a prism to distinguish between
different types of matter. Astronomers apply spectra, as well as the Doppler
effect, to determine distances between planets. Physicians use the
electrocardiograph (ECG), which traces the electrical activity of the heart,
as a nonsurgical means of diagnosing heart problems.
You can use order analysis to study, design, and monitor rotating
machinery. By measuring and analyzing sound or vibration signals
generated by a system with rotational components, you can gain a better
understanding of the system, associate features of noise and vibration
with the physical characteristics of the system, and identify system
characteristics that change with time and operating conditions.
Systems with rotational components include automobiles, airplanes,
air conditioners, and PC hard drives.
Order Analysis Basics
Order analysis and harmonic analysis have much in common. The term
harmonic refers to frequencies that are integer or fractional multiples of
a fundamental frequency.
When dealing with rotating machinery, you often can hear noise and feel
vibration created by the parts associated with the rotating components.
Parts associated with rotating components include bearings, gears, and
blades. Vibration of the rotating components creates noise and vibration
signals. The machine rotational speed is the source of the noise and