Spectral Features Based on Fault Bands
Rotating machinery produces a spectrum that reflects the harmonics of the system. These harmonics result from the relationships among the rotating components, such as gear ratios and bearing ball size. When you know the physical characteristics of your bearing or gear mesh component, you can identify the characteristic frequencies of the component where failures can occur. Fault bands are frequency bands that bound these characteristic frequencies. Rather than compute spectral metrics across the entire frequency range, you can concentrate app analysis on frequencies within the fault bands, and extract more focused and effective features that indicate specific mechanical faults.
The app provides three types of fault band-based metrics.
Gear Mesh Faults
Use Bearing Faults Features and Gear Mesh Faults Features when you know the physical parameters of your bearing or gear mesh component and want the app to compute fault bands from those parameters. Use Custom Faults Features to specify the fault bands directly. Selecting any of these options opens a tab for you to specify the parameters. When you use specify rotation or fundamental frequency using Constant (rpm) or Constant (Hz) respectively, the app overlays a preview of the fault bands on the spectral plot. If you change a parameter on the corresponding tab, the app updates the preview. In the Features section of the tab, you can select the features that you want.
The Bearing Faults Features and Gear Mesh Fault Features tabs contain similar specifications, as the following table shows.
|Type||Rotation||Physical Parameters||Defect Types||Fault Band Settings||Features|
|Bearing Faults Features||Rotation in rpm|
|Gear Mesh Faults Features|
Gear mesh parameters
The Custom Faults Features tab contains the specifications shown in the following table.
|Type||Fundamental Frequency||Fault Band Settings||Advanced Settings||Features|
|Custom Faults Features||Fundamental frequency in Hz||
For more information about the parameters used for fault band metrics, see the Live Editor task description in Extract Spectral Features. For more information about the commands that the app uses, see