Analysis and Approach of Vibration Criteria in Rotating Machinery Condition Monitoring and Diagnostic

對運轉機械的監測與診斷其振動訊號之分析及理論方法

劉朝士(C. S. Liu) ； Y. S. Shin

《中華民國振動與噪音工程學會論文集》 1994 (1994/06) Pp. 45-53

https://doi.org/10.30028/CSSVANNUAL.199406.0045

摘要

對運轉機械的監測與診斷系統來說，設定警報線值拌演了一個重要的角色，本文將船艦上fire pump所產生之振動訊號，分別在時域及頻域上進行分析。在時域上，先取出各二穿越零點間的最高值來進行統計分析，結果發現其分佈情形為對數常態分析，若將之換為速度分貝值，其分佈可轉為常態分佈，此時之μ+2σ值建議可作為警報線值。在頻率上，我們建議以l/1 Octave Band分析方法，本文並將一個正常振動訊號中加入錯誤訊號進行模擬，以比較本法與廣頻法之差別，結果顯示1/1 Octave Band分析法對速度分貝值之變化，比廣頻法敏感。

並列摘要

The setting of alarm levels plays a vital role in a machinery condition monitoring and diagnostic system. Two approaches to set vibration alarm levels using vibration signals produced by shipboard fire pumps are presented for the time and frequency domains. In the time domain, cross peak analysis (CPA) is proposed to extract the dominate peak points. The distribution of these cross peak points is found to have a lognormal distribution and can be normalized to a Normal distribution in the VdB domain. The computed μ+2σ value in the VdB domain is the suggested alarm level. In the frequency domain, 1/1 octave band analysis (OBA) is introduced. An artificial fault simulation was conducted to compare 1/1 OBA with the broadband method. The result shows that 1/1 OBA is more sensitive to changes in VdB level than the broadband method.