大型旋转机械转速测量中径向振动对输出信号的影响研究

Research of Influence of the Radial Vibration on Output Signal of the Large Rotating Machinery Instantaneous Rotated Speed Measurement

轴系的瞬时转速是反映大型旋转机械工作状态的重要基础参数。转速敏感模块的输出信号直接影响测试系统的准确性,其中,测速齿轮-电涡流传感器是重要的转速敏感元件。本文研究了大型旋转机械轴系径向振动对电涡流传感器的输出信号的时域、频域波形及整体趋势等方面的影响。结果表明:径向振动中平行分量产生的低频信号会叠加在测速齿轮输出的时域信号的包络波形上,影响输出信号的包络幅值、整体幅值,进而极大影响转速提取的准确性。径向振动的垂直分量对测速齿轮的输出信号产生了调频效应,影响程度随“垂直比位移”的增大而增大。

The rotated speed of shaft system is one of the important unit parameters of large rotating machinery.Based on the relationship between measuring time interval and rotated period,the rotated speed measure method can be classified as the sub-period,synchronous and ultra-period method.Among these ways,the results of sub-period method can be considered as the instantaneous rotated speed.The output signal of rotor speed measure module is the fundament of the measure method.The theoretical analysis was carried out to research the influence of shaft radial vibration on the output waveform of speed measuring gear and eddy current transducer,such as the characteristic in time and frequency domain,the amplitude of waveform et al.The results show that the low-frequency signals generated by the parallel component of radial vibration superpose the corresponding voltage signal on the overall and envelope amplitude of the output waveform of the gear;consequently,it influenced the subsequent thresholding and accuracy of speed extraction.The vertical linear velocity influence the frequency of the transducer output signal.The impact increase with the increasing of the“ratio of vertical displacement”.