Detection of insufficient lubrication in generator bearings
According to research by RKB*, 80% of premature rolling bearing failures are due to problems with lubrication. A lack of lubrication causes increased friction and increased friction causes structure-borne noise emissions in the range above 20 kHz, which is called the ultrasonic range. In a small hydropower plant (180 KW), this effect was exploited to specifically optimise the lubrication cycle.
Due to their small size, small hydropower plants have to constantly optimise their maintenance costs in order to be competitive on the electricity market. Although power plants are usually designed for a service life of many decades, these targets are often not met due to poor operation. Rolling bearings have to be replaced well before the end of the planned service life, turbines are severely damaged due to cavitation (see cavitation case study).
In order to maximise the service life of the roller bearings, the lubrication indicator was recorded in addition to the standard prediction of the remaining service life using Senzoro's Ultrasound Condition Monitoring System. Based on more than 20 000 measurements on rolling bearings, a database was built up to infer the existing friction on the basis of the ultrasonic measurement.
During the second measurement within the scope of the cooperation, no roller bearing damage was detected, but a high lubrication indicator, as well as a clear increase compared to the first measurement.
Adjusted lubrication cycle
To avoid premature bearing damage, the lubrication cycle was adjusted accordingly. The follow-up measurement showed values in the normal range again.
Conclusion
In addition to the reliable detection of bearing damage using artificial intelligence, the Ultrasound Condition Monitoring System can also help to increase the service life of components by detecting "life-reducing" conditions such as insufficient lubrication. The "open data" principle ensures that the generated data is made available to the company in an open format and thus freely usable.
* The Most Common Causes of Bearing Failure and the Importance of Bearing Lubrication
Author: Dipl. Ing. Mag. Markus Loinig, Senzoro GmbH
Email: markus@senzoro.com
