大轴膨胀对振动测量影响的原因分析及处理方案

针对韶关发电厂9号机组7号瓦（发电机励磁机端）Y方向大轴振动指示偏差大的故障进行了系统分析。通过多次试验检测，发现故障产生的原因并不是测量元器件的质量问题或安装调试的问题，而是由于大轴受热膨胀使振动传感器的有效检测面积变小，不能满足传感器所要求的最小测量面积。针对这种情况，并结合现场具体条件，制定了合理可靠的处理方案。

Causal Investigation and Solution of Main Shaft Expansion Influencing Vibration Measurement

Systematic analysis was made aiming at the large deviation of the Y-direction main shaft vibration indication on No.7 bearing bush(exciter end of generator) of Unit 9 in Shaoguan Power Plant.Upon multiple times of detection,it was found that the fault was not caused by the quality,installation or debugging problem of the measuring element,but by the expansion of the heated main shaft that led to the decrease in effective detection area of vibration sensor and the failure to meet the minimum measuring area as required by the sensor.Accordingly,rational and reliable solution was formulated in combination with specific conditions on site.