摘要
When operating speed or load is changed, or mechanical faults appear in machinery, many dynamic signals coming from running machinery are nonstationary. It is difficult to analyse these kind of signals. Timefrequency(scale) analysis methods of WignerVille distribution (WVD), short time Fourier transform (STFT), and wavelet transform (WT) provide powerful new tools to analyse and diagnose nonstationary signals of machinery. This paper adopts these new methods to analyse vibration signals of a metallurgical rolling mill and a mining electric excavator, and to diagnose their operating conditions and mechanical faults. Mechanical shock, friction, wear and additive impulse are revealed successfully from nonstationary operating conditions.
When operating speed or load is changed, or mechanical faults appear in machinery, many dynamic signals coming from running machinery are nonstationary. It is difficult to analyse these kind of signals. Timefrequency(scale) analysis methods of WignerVille distribution (WVD), short time Fourier transform (STFT), and wavelet transform (WT) provide powerful new tools to analyse and diagnose nonstationary signals of machinery. This paper adopts these new methods to analyse vibration signals of a metallurgical rolling mill and a mining electric excavator, and to diagnose their operating conditions and mechanical faults. Mechanical shock, friction, wear and additive impulse are revealed successfully from nonstationary operating conditions.
