室外機之振動噪音檢測分析與評估

隨著生活品質提升，室外機的振動噪音已逐漸成為值得關注之議題。在室外機系統中，壓縮機為主要噪音來源，儘管壓縮機為室外機系統激振元件，但室外機系統之振動噪音仍會與其他元件相互影響。本文主要目的在建立室外機系統於運轉情況下之振動噪音檢測分析手法。分別對室外機系統進行收受端測試（Receiver Test）及路徑端測試（Path test）。使用麥克風及加速度計為感測器量測室外機於製熱工況下，不同壓縮機轉速之振動噪音。於噪音頻譜可看出此室外機之噪音特性為Broad band noise。從不同轉速下之振動頻譜時頻圖可看出噪音與振動頻譜兩者之關聯性，藉此找出時頻圖中貢獻度高之頻帶及頻率。室外機系統路徑端測試採用實驗模態分析（EMA）方法，對室外機機殼、壓縮機及管路進行量測。路徑端測試結果可用以輔助噪音診斷，結果顯示室外機系統中機殼之前板、右側板、左側板、上蓋及配管為主要影響噪音之相關結構。本文除在建立完整振動噪音檢測分析手法外，也透過實驗模態分析輔助判斷可能與噪音相關之室外機結構，未來此振動噪音檢測手法也可應用於其他案例中。

關鍵字

室外機；收受端測試；路徑端測試；實驗模態分析

並列摘要

The outdoor unit of conditioner is of concern for its noise and vibration (N&V). The major noise source in the conditioner that consists of many components may be blamed from the compressor. Although the compressor is the component that can excite the whole system, the outdoor unit's N&V can be interaction effect among components. This work develops the measurement plan to examine the operating N&V for the outdoor unit. Both the Receiver and Path Tests are conducted, respectively. Several microphones and accelerometers are placed accordingly to measure the system's N&V for Receiver Test at different running speeds of compressor for air-conditioner mode. The noise spectrum can be observed as the broad band characteristics. The vibration spectrum as well as the time-frequency plot at different speeds can be related to noise spectrum and identified for the critical bands of frequencies that contribute to N&V significantly. The structural modal testing on the case body and inner components, such as the compressor and pipe lines, of the outdoor unit is carried out and known as the Path Test, i.e. experimental modal analysis (EMA). Results from Path-Test can assist to diagnosis the structural path for noise transmission. The case bodies and pipe lines are strongly related to the radiated noise at some spectral response. Other than the Receiver Test for N&V on the outdoor unit, this work also performs EMA on the components of outdoor unit and helps to identify the noise radiation from the structural path. The experimental approach in studying N&V of outdoor unit can be applied to other products as well.

並列關鍵字

outdoor unit of conditioner ； receiver test ； path test ； experimental modal analysis (EMA)

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