• Journal of Applied Reliability
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• v.17 no.4
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• pp.316-324
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• 2017

Purpose: The purpose of this study is to determine the replacement cycle applied age replacement policy by reliability analysis based on railway vehicle contactor's failure history data. Method: We performed reliability analysis based on railway vehicle contactor's failure history data. We found a suitable distribution by goodness of fit test and predicted the reliability through estimation of scale & shape parameter. Considering cost information we determined the replacement cycle that minimize the opportunity cost. Result: Suitable distribution was the Weibull and scale parameter & shape parameter are estimated by reliability analysis. The replacement cycle was predicted and MTTF, $B_6$ percentile life were suggested additionally. Conclusion: We confirmed that failure rate type of railway vehicle contactor is degradation model having a time dependent characteristic and examined the replacement cycle in our country's operating environment. We expect that this study result contribute to railway operation agency for maintenance policy decision.

• Journal of the Korean Society for Railway
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• v.19 no.2
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• pp.117-123
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• 2016

High speed circuit breakers(HSCB) interrupt the generated arc within the arc chute to turn off the electricity flowing through the main circuit to prevent ground faults. In order to explore the arc generated from the contactor operation, arc definition, establishment of arc interruption method, and analysis of magnetic driving force are required. In this paper, arc interruption capability has been estimated by exploring the difference in magnetic flux density of Lorenz forces using finite element analysis. In addition, since the number of grids and changes in the grid shape within the arc chute influence the formation of the inner magnetic field, its effects have been explored to enhance arc interruption capability. Assessment of interruption capability and analysis of grid shape, with rated operating current, are reported.