With Dynamox, Nexa avoids a corrective maintenance cost of R$31,000

March 5, 2024

What if you could reduce corrective maintenance costs? With Dynamox solution, Nexa has detected an early failure in a bearing, intervened, and avoided spending R$31,000. Check it out!

Mining company Nexa relies on Dynamox sensors installed in its industrial assets at the Vazante unit in Minas Gerais. With constant monitoring, automated data collection, and analysis on the Web Platform, this partnership between the companies has already ensured other successful cases, and now we present another one.

Arley Campelo Nunes, predictive maintenance technician, shared with the Dynamox team this occurrence in an underground mine ventilation fan.

In November 2023, during online monitoring, an increase in equipment vibration levels was noticed. Additionally, analysts were able to detect bearing backlash frequencies in the asset’s bearing housing. Check out the results obtained by Nexa in the analysis:

Spectral analysis of bearing failure

Waveform Autocorrelation

The Autocorrelation Tool aids in the identification of periodic signals. Therefore, by using autocorrelation alongside circular waveform visualization, it’s possible to conduct a clear analysis of the impacts generated by backlash in the set during shaft revolutions.

In the figure below, each prominence demonstrates an impact during the revolution.

Bearing fault waveform autocorrelation

Spectral Waterfall

Using the spectral waterfall tool, it was possible to observe the evolution of the vibration spectrum in acceleration, with its levels decreasing after the intervention on the asset in January.

That is, the lines in red, orange, and blue (post-intervention) no longer register the levels of the previous ones. Check in the image below:

Finally, using spectral analysis tools, it was possible to identify signs of backlash. In the figure below, markers of RPM can be seen indicating multiple harmonics of the nominal shaft frequency, a behavior characteristic of backlash in the components.

Acceleration envelope - bearing failure

With the early identification of the failure, the Nexa team was able to perform a planned shutdown, without impacting the equipment availability or generating additional corrective maintenance costs.

Avoiding the cost of corrective maintenance

During the scheduled shutdown, the Nexa team opened the asset bearing housing, confirmed the existence of backlash, and performed the necessary intervention. As a result of this procedure, as also shown in the graphs, the vibration levels of the exhaust fan returned to normal.

Thanks to Dynamox’s automated data collection system, continuous and accurate sensor monitoring, and the proactive action of analysts and maintenance team. The need for corrective maintenance or major damages such as bearing breakage, shaft damage, bearing housing damage, and equipment unavailability was avoided.

It is estimated that the savings generated by the early identification of the fault and preventive action exceeds R$ 30,000.00, thus avoiding this cost of corrective maintenance.

Next, check the photo of the bearing where it’s possible to see the sliding marks caused by backlash

Corrective maintenance costs: bearing failure signs

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