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近年来,为防止噪声公害,强烈要求生产机械降低噪声。对此要求,日立公司由于对高压大容量开启防滴型和全封闭外扇型异步电动机按装了性能优良的消声器,低噪声HIPACT4800系列[75dB(A)级]电动机已经制成,已具有许多实际制造的经验和产品。研制时,分析了消声器的风压损失和减声效果,整理成丰富的设计资料,利用这些结果,采用简单的结构,研制了减声效果好而且风压损失小的消声器。一、绪言为防止噪声公害,对于作为一般生产机械噪声源之一的异步电动机,降低噪声的要求日益严格。日立公司对于高压大容量高速电机,由于采用轴向通风冷却方式,通过转子铁心的电动机元周方向传出的噪声大幅度降低,由于采用了高效率的风扇,电动机本身产生的噪声就低。
In recent years, in order to prevent noise pollution, the production machinery is strongly demanded to reduce the noise. In response, Hitachi has introduced a low-noise HIPACT 4800 series [75dB (A) class] motor equipped with high-performance mufflers for high-pressure, large-capacity drip-proof and fully enclosed fan-type asynchronous motors, The actual manufacturing experience and products. In the course of development, we analyzed the wind pressure loss and noise reduction effect of the muffler and arranged them into a wealth of design data. Using these results, a simple structure was adopted to develop a muffler with good sound reduction effect and small wind pressure loss. I. INTRODUCTION To prevent noise nuisance, the demand for noise reduction is becoming more and more stringent for induction motors that are one of the common mechanical noise sources. Hitachi Ltd. For high-voltage and high-capacity high-speed motors, the use of axial-fan cooling reduces the noise radiated through the rotor core in the circumferential direction of the motor. Due to the high efficiency of the fan, the noise generated by the motor itself is low.