This module is a part of “Engine Carbon Brushes Replacement” project. During the project, some intermediate conclusions were made and some fact were collected. These conclusions and facts need further research.

By comparison an IQRs, we can conclude that Carbon Brushes of Cement Mill 11 have a most heterogeneous lifespan- it means that factors determinate lifespan of each carbon brush relatively stronger than on the other mills.


Small IQR of CM4, CM12, and RMB says that general conditions have a stronger influence on brushes lifespans relatively to the other mills. At the same time, the smallest Q2 of CM4 might point to the worst conditions for carbon brushes of CM4 engine. At the same time biggest Q2 of RMA point to dramatically better conditions for carbon brushes of RMA engine (???).



Despite we have only 10 observations (mills), Let’s check whether there is some correlation between engine start phase and end carbon brush lifespan. As parameters represent carbon brush lifespan I take IQR and percentile 50 and as parameters represent engine start phase I take percentile 50, percentile 75, and a maximum value (for each mill).

At that moment, It looks like that, there is no any significant correlation, between duration of engines “start” phase and brushes lifespan. The issue will be learned for each mill separately.

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Carbon brushes replacements - “C” value brings prominent information gain. “C” value gives information about the horizontal location of the carbon brush. This means, that every horizontal position has a significantly different number of carbon brushes replacements during a period of time covered by the dataset. Let’s find a percent of the replaced brushes for each “C” position.

How it was expected, the carbon brush lifespan significantly depends on its horizontal position.

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It was shown, the average value of dust emission significantly high for short work periods, as well as a lower average power value. Actually, every cement mill start accompanied by relatively high dust emission, during the work time current dust emission value has been stabilized and the average value decreases. Short periods (according to the chart) less than 50 min or so, not enough to reduce the average dust emission value and increase the average power value- that the reason for the correlation between mill engine power and dust emission.

Based on this research, we can conclude - in order to reduce dust emission, better to reduce the number of mill starts and increase the duration of each work period.

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