Processing for Improved Spectral Analysis

Eric Bechhoefer, Brandon Van Hecke, and David He
Submission Type: 
Full Paper
AttachmentSizeTimestamp
phmc_13_006.pdf688.43 KBOctober 11, 2013 - 1:10pm

The Fast Fourier Transform (FFT) is the workhorse of condition monitoring analysis. The FFTs’ assumption of stationarity is often violated in rotating machinery. Even in a six second acquisition on a wind turbine, the shaft speed can change by 5%. For Shaft and Gear analysis, this is mitigated through the use of the time synchronous average. For general spectrum analysis, or bearing envelope analysis, there is no such mitigation: one hopes that the effect of variation in shaft speed is small. Presented is a time synchronous resampling algorithm which corrects for variation in shaft speed, preserving the assumption of stationarity. This allows for improved spectral analysis, such as used in bearing fault detection. This is demonstrated on a real world-bearing fault.

Publication Year: 
2013
Publication Volume: 
4
Publication Control Number: 
006
Page Count: 
7
Submission Keywords: 
Bearing Analysis
Stationarity
FFT
Spectral Analysis
Resampling
Submission Topic Areas: 
Data-driven methods for fault detection, diagnosis, and prognosis
Submitted by: 
  
 
 
 

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