Engine Carbon Brushes Replacement-
Raw Material Mill C
St.Dmitry
March 25, 2017
a) to build convenient for further work datasets based on the provided raw data;
b) preliminary separate exploratory data analysis of carbon brushes replacement of Raw Material Mill C engine;
c) care by outliers.
The input of the module is a csv file. The file contains an unordered dataset, with provided information of engine inspections since 2004 for each engine carbon brush. In case carbon brush was replaced due to deterioration - the event is signed by “1”, otherwise by “0”.
The outputs of the module are convenient for further work datasets based on the provided raw data.
Statistic information of maintenance periods and cases of carbon brushes replacement due to deterioration:
## Cement Mill 11 (January 2004 - February 2018)## Maintaneince days summary:## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 0.00 20.25 24.00 27.05 28.00 532.00##
## Maintaneince days Outleirs:## lowerFarOut lowerOutliers upperOutliers upperFarOut
## -3.000 8.625 39.625 51.250##
## Replacement periods summary:## Min. 1st Qu. Median Mean 3rd Qu. Max.
## 1.0 25.0 206.0 261.7 352.0 1728.0##
## Replacement periods upperOutliers:## upperOutliers upperFarOut
## 842.5 1333.0Graphical Presentation of the Data:
Box Plots of the “maintenance periods” and “cases of carbon brushes replacement”
Low “FarOut” Actually, low farOuts points (days of carbon brush replacement) mean that carbon brushes were replaced on the same day or after few days. In both cases, low farOuts might be entered same information twice- and must be removed from dataset.
Low “FarOut”
## Mill C R brushName brushType phase fromDate toDate Days
## 20 RMC 1 1 C1R01 CM-2 U 2017-05-10 2017-05-11 1
## 55 RMC 1 3 C1R03 CM-2 U 2017-05-10 2017-05-11 1
## 89 RMC 1 5 C1R05 CM-2 U 2017-05-10 2017-05-11 1
## 163 RMC 2 2 C2R02 CM-2 V 2017-05-10 2017-05-11 1
## 264 RMC 2 8 C2R08 CM-2 V 2017-05-10 2017-05-11 1
## 301 RMC 3 2 C3R02 CM-2 W 2017-05-10 2017-05-11 1
## 412 RMC 3 8 C3R08 CM-2 W 2017-05-10 2017-05-11 1
## 16 RMC 1 1 C1R01 CM-2 U 2017-02-19 2017-02-22 3
## 51 RMC 1 3 C1R03 CM-2 U 2017-02-19 2017-02-22 3
## 67 RMC 1 4 C1R04 CM-2 U 2016-04-28 2016-05-01 3
## 85 RMC 1 5 C1R05 CM-2 U 2017-02-19 2017-02-22 3
## 120 RMC 1 8 C1R08 CM-2 U 2016-04-28 2016-05-01 3
## 137 RMC 2 1 C2R01 CM-2 V 2017-02-19 2017-02-22 3
## 159 RMC 2 2 C2R02 CM-2 V 2017-02-19 2017-02-22 3
## 182 RMC 2 3 C2R03 CM-2 V 2017-02-19 2017-02-22 3
## 213 RMC 2 5 C2R05 CM-2 V 2017-02-19 2017-02-22 3
## 253 RMC 2 8 C2R08 CM-2 V 2016-04-28 2016-05-01 3
## 260 RMC 2 8 C2R08 CM-2 V 2017-02-19 2017-02-22 3
## 275 RMC 3 1 C3R01 CM-2 W 2016-04-28 2016-05-01 3
## 297 RMC 3 2 C3R02 CM-2 W 2017-02-19 2017-02-22 3
## 323 RMC 3 3 C3R03 CM-2 W 2017-02-19 2017-02-22 3
## 356 RMC 3 5 C3R05 CM-2 W 2017-02-19 2017-02-22 3
## 384 RMC 3 7 C3R07 CM-2 W 2016-04-28 2016-05-01 3
## 391 RMC 3 7 C3R07 CM-2 W 2017-02-19 2017-02-22 3
## 408 RMC 3 8 C3R08 CM-2 W 2017-02-19 2017-02-22 3First quantile - most frequently replaced carbon brushes.
Here, it is easy to find out places, where carbon brushes were replaced significantly more frequently than a majority of carbon brushes of this engine. Presumably, these carbon brushes were affected by local factors (like a local clamping spring) more than common reasons (for this engine). But here, the situation significantly better than in the other mills- there are no cases of frequently replaced carbon brushes.
Fourth quantile - most rarely replaced carbon brushes.
This chart provides information about “frozen” (rarely replaced) carbon brushes. Probably “frozen” brushes have a relatively weak clamping spring - as result, the carbon brush, apparently, did not do the job at all. -For example carbon brush C2R04 - was not deteriorated for about five years (The criterion for replacement is the size (deterioration) of the carbon brush).
We should take into account, that there are upper outliers in the maintenance list - the reason for extremely long intervals between maintenance is probably data loss of maintenance cases:
## dateDiff fromtDate toDate
## 1 48 2004-03-29 2004-05-16
## 2 41 2004-06-30 2004-08-10
## 3 48 2013-10-28 2013-12-15
## 4 532 2013-12-15 2015-05-31
## 5 156 2016-05-17 2016-10-20
## 6 64 2017-09-25 2017-11-28There is a chance that deteriorated carbon brushes had been replaced during those periods, but we have no information - and as result, we see the lifespan of them as outliers:
## brushName fromDate toDate Days
## 1 C1R01 2013-05-27 2016-01-07 955
## 2 C1R04 2013-07-21 2015-12-10 872
## 3 C1R06 2013-05-27 2016-02-21 1000
## 4 C1R07 2008-03-04 2010-11-10 981
## 5 C1R07 2013-05-06 2016-02-21 1021
## 6 C2R01 2008-04-21 2010-11-10 933
## 7 C2R01 2013-07-21 2016-01-07 900
## 8 C2R02 2008-04-21 2010-08-29 860
## 9 C2R04 2013-05-27 2018-02-18 1728
## 10 C2R05 2013-05-06 2016-02-21 1021
## 11 C2R07 2013-08-14 2015-12-10 848
## 12 C2R08 2008-03-04 2010-08-29 908
## 13 C3R01 2005-11-08 2008-04-21 895
## 14 C3R06 2013-08-14 2015-12-10 848In order to exclude the uncertainty- whether carbon brushes lifespan outliers are true, or results of information loss- we can test which of these time periods are overlapping (outliers of periods between maintenance and outliers of periods between carbon brushes replacement).
According to the table, except of C1R07(4), C2R01(6), C2R02(8), C2R08(12), C3R01(13), other lifespan outliers might be a result of the lost information. For example, it looks like carbon brush C2R04(9) was not replaced for about five years, but this periods are overlapped with four periods of lost information, during which carbon brushes might have been replaced for several times.
For sure, we can only say, that C1R07(4), C2R01(6), C2R02(8), C2R08(12), C3R01(13) carbon brushes were not replaced more then two years. Except for those five cases, other 9 outliers are better to be removed from the dataset.
In the same way possible to analyze current data in order to predict probable problem (“burned” or “frozen” carbon brushes). This chart is based on current data, taken at February 2018.
“Importance” (to put attention) provides visual information about the number of days since last replacement- lower than second quintile, or upper then third quintile. The importance is calculated by the following principles: Maximum value - 10, is equivalent to the maximum distance from the second quantile down (for the low values -“burned” brushes) and from the third quantile up (for the upper values- “frozen” brushes) found in the whole engine history. The minimum value “1” - the number of days since last replacement, lays in the second or third quantiles.
Colors: green- the number of days since last replacement lays in third or second quintile;
red- “burned” brush - the number of days since last replacement and lifetime of the previous brush in this place lay in the first quintile;
blue- “frozen” brush- the number of days since last replacement lays in the fourth quintile.