Russian Rail Shop Competition Results
Diagnostics and Condition Prediction on the Ekaterinburg division of the railway using the Diagnostic Rolling Element Analysis Module (DREAM)
The condition of the rolling element bearings is a vital element of the operating efficiency of railway locomotives and cars. The study of the repair cases on the Ekaterinburg division of the railway during several years showed that 44% cases of non-planned repairs of electric locomotives were due to the failure of the bearings and gearboxes. These repairs took about 58% of all non-planned repair time which implies that repairs involving bearing and gearboxes is the most complicated and time consuming repair work.
The financial losses of the railroad due to the occasional failure of these units exceeded the costs of the installation of the diagnostic complex based on the DREAM software by six times. That means that, if the the number of unpredicted failures is reduced by 20%, the diagnostic complex using DREAM will cover all the installation expenses.
The first example presented here was on a type ChS-2 locomotive . This locomotive was tested because of increased vibration noise in the region of a small gear in the transmission. It was suspected that the gear was severely worn along with the bearings. After the measurements and diagnostics with DREAM, it was found that the bearings were in good condition and there was no need to change them. After disassembling the gearbox, this diagnosis was confirmed by visual inspection.
The next case was August 31, 1994. A bearing in the main electric motor of the same type locomotive was diagnosed. The program automatically identified a severe defect of cage wear and spalls of rolling element bearings and recommended replacement of the bearing.
The last case involved diagnostics of two bearings in the wheel box by one measurement. After the measurements of the envelope spectrum of high frequency vibration, severe wear of the outer race of one on the bearings was diagnosed. DREAM gave a prediction for 2 days safe operation till the next measurement should be made. This made possible postponing the repair of the bearing till the railway car could be brought to the maintenance shop. Moreover, the bearing was not replaced. As there was a defect of outer race, the held race, the race was just 180 degrees rotated and re-mounted in place. Now the load applied on good bearing surface and a prediction of safe operation of the bearing for the next month was made by DREAM.
After testing DREAM on the Ekaterinburg division of railway (Sverdlovsk-Passengers locomotive depot) the following conclusions were made:
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