The Noise Source Identification of Refrigeration Compressor by Signal Processing Technique

**C. H. LEE It is well known that the major noise source of a refrigerator is the compressor, and due to the tendency of higher quality and more lighter weighty of manufactured goods, the importance of of prevention and reduction of noise is increasing. In this paper, in order to prevent and reduce such noise, sound pressure level and acoustic intensity are measured for the compressor, and the results of these measurements, the noise radiation characteristics of the compressor are identified. Also the experimental modal analysis is applied to the compressor to identify the noise source. INTRODUCTION Recently, noise and vibration problems are on the rise many times in the electrical home appliances, and especially stressed by the trend of lighter weighty and higher quality goods. It is complicated to find the generating source and propagating path of noise in the compressor which are the main noise SOUTce in a refrigerator. The rotating forces generated from the driving unit in the compressor act as compression force and rise to mechanical vibration and pressure pulsation. Also the forces excite the compressor shell, and produce structure-oome sound and air-borne sound through the propagating path. As the above, noise problem in the electrical home appliances is important factor which detennines not only the performance and quality of goods, but also the domestic environment. For the purpose of producing the noiseless refrigerator that will increase our selling competitive power, it is essential to examine the noise and vibration phenomena and identify the exact generating source to work out a countermeasure by using the various analysis method. In this paper, the noise source identification by measllTing sound pressure and acoustic intensity is introduced. And the relation between noise and vibration is also identified by applying modal analysis technique to the compressor. THEORETICAL ANALYSIS Basic theory of acowdic intensity In elasto-acoustic system, the acoustic intensity is a vector quantity defined as a product of the acoustic pressure and the corresponding particle velocity at a given point. When there is no flowing, the one dimensional equation of motion is