2019 Volume 47 Issue 2 Pages 91-100
The lubrication analysis is an effective method for the condition monitoring and diagnosis of power plants. The method is still in a trial stage in pumps for irrigation and drainage. The lubricating oil were sampled and analyzed annually from 2011 to 2014 from two gearboxes for drainage pumps in operation for 18 years. The viscosity was abnormally low and the particle number concentration in oil, CNp was high in 2012. The Fe concentration, CM(Fe), and the CNp of large particles increased significantly in 2013. A gear tooth failure was discovered in 2014, when a particle that is characteristic to fatigue wear was found in the oil.
For failure diagnosis, the criteria for CNp and CM(Fe) are necessary and the observation of wear particles is helpful. For the early-stage detection of abnormal symptom, it is useful to monitor the increase rate of CNp in each particle size range.
