In large rotating machinery using filmatic bearing ( turbogenerator , air compressor , etc . ) there is a potential trouble from impefect installation or running conditions , a metals " contact between rotors and shells . the trouble is usully called rubbing . the advantage of ae technologe in the rubbing diagnosis and early detection is showed . instead of classical ae characteristic parameters ( counts , amplitude , energy , duration and the other ones ) a new feature extraction by frequency analysis of ae envelop signals is discussed . both research of ae process and field experements indicate that periodic components in the envelop spectrum related to rotational speed increase evidently at the beginning of rubbing production , hence are highly sensitive to the rubbing fault diagnosis . according to the new design an acoustic emission equipment for the rubbing diagnosis named buaa ae testing system is developed and described 汽轮发电机、空气压缩机等采用油膜支撑的大型转动机械，由于安装或运行中的原因，在转子旋转过程中，可能和器壁发生轻微的摩擦和碰击，简称碰摩.声发射技术在碰摩发生特别是故障早期诊断上有优越性.本系统的特点是没有沿用传统的计数、幅度、能量和持续时间等声发射特性参数，而是在声发射包络信号的频率分析中进行特征提取.声发射发生的过程分析和现场试验都表明这种方法对碰摩检测很敏感，在碰摩发生的起始阶段，包络谱中与转速同步的周期性分量显著增加.根据这种新的设计思想自行研制了buaa碰摩声发射检测仪并对此作了介绍
