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Abstract: Because of the limit of Heisenberg-Gabor inequality, the
wavelet scalogram has low frequency concentration at small scales and
low time concentration at large scales. In addition, misleading
interference terms would appear in the scalogram at some conditions. All
of those would influence scalogram analysis seriously. Reassignment
method can improve the concentration of the scalogram and weaken the
interference terms to certain extent, thus the readability of the
scalogram can be improved. The experimental data of three kinds of
faults: Rub-impact, coupling misalignment and the actual measurement data
from a pumped storage power generator unit are analyzed by scalogram and
reassigned scalogram, and the results by ordinary frequency analysis are
also given. The comparison among three kinds of analysis results is
carried out, and the comparison results indicate that the scalogram can
not only reveal the time-frequency features of vibration signal but also
extrude components of low energy. Therefore it is suitable to extract
features of faults at early stage.
Key words: Wavelet Scalogram Fault diagnosis Time-frequency
analysis
CLC No: TH165.3
国家“九五”攀登计划(PD9521908Z2)和国家自然科学基金(50105007)资助项目.
Received 20010326, received
in revised form 20010710
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