# Design and Testing of a Measurement Device for High-Speed Bearing Evaluation
## 4 Conclusions  
The presented contribution is a fundamental segment of a research project, focused on the design and implementation of a measuring and testing device to assess the impact of nanoparticles on the functional properties of rolling bearings at high speeds.  
The objective of the measurements is to empirically evaluate the influence of nano additives on the operational parameters of bearings. The research analyzes how nanoparticles affect bearing operation, utilizing technical measurements, and assessing changes in vibrations in two groups of bearings:  
Group A: 8 bearings tested with the original lubricant.  
Group B: 8 bearings tested with lubricant containing nano additives.  
Groups are formed based on initial measurements of dynamic responses, identifying bearings with significant anomalies. Tests gradually increase from 70,000 RPM to 110,000 RPM. Selected bearings undergo load tests and measurements of operational properties.  
Dynamic response measurements within the speed range from 40,000 RPM to 110,000 RPM enable the detection of characteristic changes due to lubrication with original and modified lubricants containing nanoparticles. High-frequency characteristic measurements at 110,000 RPM and, after 5 min of continuous operation, allow us to compare lubrication effects on bearings' vibrations under stable conditions and after 5 min of operation. FFT analysis provides an additional indicator in high-frequency vibration analysis.  
As a concluding diagnostic method, acoustic emission measurement, a common approach in diagnosing the operational behavior of rolling bearings, is implemented. Evaluations are conducted at 110,000 RPM and after five minutes of continuous operation.  
The subsequent phase involves identifying and preparing suitable nanoparticles for the lubricant in Group B, considering their size, shape, and chemical properties for optimal application in this specific research context.  
Figure 17: Bearing L027.6, acoustic emissions—FFT spectrum of Group A before relubrication: upon reaching 110,000 RPM (**left**); after 5 min of operation at 110,000 RPM (**right**).  
Figure 18: Bearing L093, acoustic emissions—FFT spectrum of Group B before relubrication: upon reaching 110,000 RPM (**left**); after 5 min of operation at 110,000 RPM (**right**).  
**Author Contributions:** Conceptualization, M.D. and T.K.; methodology, M.D. and T.K.; software, T.K.; validation, M.D., T.K. and T.C.; formal analysis, M.D. and T.C.; investigation, M.D. and T.K.; resources, M.D.; data curation, M.D., T.K. and T.C.; writing--original draft preparation, M.D. and T.K.; writing--review and editing, M.D. and T.C.; visualization, T.K. and T.C.; supervision, M.D., T.K. and T.C.; project administration, T.K.; funding acquisition, T.K. All authors have read and agreed to the published version of the manuscript.  
This work was funded by the Ministry of Education, Science, Research and Sport of the Slovak Republic within project VEGA No. 1/0823/21.  
Not applicable.  
The data presented in this study are available on request from the corresponding author. The data are not publicly available due to privacy reason.  
The authors declare no conflicts of interest. The funders had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript; nor in the decision to publish the results.