• Title, Summary, Keyword: Imperfect Maintenance

Search Result 28, Processing Time 0.024 seconds

Imperfect Preventive Maintenance Plan of Generation Unit Using Quasi-renewal Theory (Quasi-renewal 이론을 이용한 발전설비의 불완전한 유지보수 예방정비 계획)

  • Kim, Hyung-Jun;Byun, Yoong-Tae;Kim, Jin-O;Lee, Jun-Kyong
    • The Transactions of The Korean Institute of Electrical Engineers
    • /
    • v.57 no.5
    • /
    • pp.735-740
    • /
    • 2008
  • Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. For the most of the current power equipment maintenance, the state of the equipment after maintenance is assumed to be becoming 'as good as new ones' state. However, the state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

An Introductory Study on Imperfect Maintenance Effect in Rolling Stocks

  • Kim, Jong-Woon;Han, Seok-Yun;Chung, Jong-Duk
    • International Journal of Railway
    • /
    • v.1 no.2
    • /
    • pp.59-63
    • /
    • 2008
  • The maintenance effect is a peculiar factor applied to repairable systems such as rolling stocks. Conventional statistical analysis for failure times takes into account one of the two following extreme assumptions, namely, the state of the system after maintenance is either as "good as new" (GAN, perfect maintenance model) or as "bad as old" (BAO, minimal maintenance model). Most of the papers concerning the stochastic behavior of railroad systems assume two types of maintenance: perfect and minimal maintenance. However, Lee, Kim & Lee (2008) analyzed the failure data of a door system in Metro EMU and the effect of preventive maintenance was imperfect. It is seen that the imperfect maintenance is of great significance in practice. This article describes how to deal with the maintenance effect in reliability studies of rolling stocks. Maintenance policies under imperfect maintenance are described and the method is proposed to evaluate their performance.

  • PDF

A Study on the Characteristics of the Imperfect Maintenance Models (불완전 보전모형의 특성에 관한 연구)

  • Yi, Jin-Shik;Lyu, Jeong-Mo
    • IE interfaces
    • /
    • v.14 no.3
    • /
    • pp.272-285
    • /
    • 2001
  • Proper maintenance techniques have been emphasized in recent years due to increased safety and reliability requirements of systems, increased complexity, and rising costs of material and labor. In the related literature, most studies assume that the system after cm or pm is 'as good as new'(perfect maintenance) or 'as bad as old'(minimal maintenance). But many maintenance activities may not result in these two extreme situations but in a complicated intermediate one. Therefore, perfect maintenance and minimal maintenance are not practical in many actual instances and so realistic imperfect maintenance should be modeled. For this study, various imperfect preventive maintenance models are investigated and analyzed. From the analysis of the imperfect maintenance models modeling methods and maintenance policies are arranged and presented some tables providing informations to the maintenance managers.

  • PDF

Preventive Maintenance Plan of Power System Unit Considering Imperfect Maintenance (불안전한 유지보수를 고려한 전력 설비의 예방 정비 계획)

  • Byeon, Yoong-Tae;Kim, Hyung-Jun;Kim, Jin-O;Kim, Hyung-Chul
    • Proceedings of the KIEE Conference
    • /
    • /
    • pp.328-330
    • /
    • 2007
  • Recently, the research of PM (Preventive Maintenance) method on the RCM(Reliability-Centered Maintenance) of the system equipment is being actively advanced for a few years. The state of the power equipment is maintained like the states of the between 'as good as new ones' and 'as bad as old ones' by imperfect Maintenance that implies the life decrease of the equipment by frequent breakdown, the error of maintenance process, and so on. So, the Maintenance method considering the real case has to reflect Imperfect maintenance than perfect maintenance. This paper suggests the Preventive Maintenance method by using Quasi - Renewal Theory for the gas turbine equipment as deliberating the imperfect maintenance for the real cases.

  • PDF

A case study on evaluating the effectiveness of maintenance policies under imperfect maintenance (시뮬레이션을 통한 불완전 유지보수하에서의 유지보수 정책의 효율성 평가에 관한 사례 연구)

  • Lee, Duk-Gyu;Lee, Hi-Sung
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.1539-1544
    • /
    • 2008
  • There is a existing study dealing with the case that the effect of preventive maintenances to restore the door system is imperfect. When the effect of the preventive maintenance is imperfect, we need to consider the maintenance effect for making reliable and economical maintenance policies. The maintenance policies applicable for imperfect maintenance cases are considered and their effectiveness are evaluated through simulation in cases of passenger door system:PDS.

  • PDF

Optimal Periodic Preventive Maintenance Schedule When Preventive Maintenance is Imperfect (예방보전이 불완전할 때 최적 주기적 예방보전 계획)

  • Kim, Dae-Kyung;Shin, Sang-Wook;Lim, Jae-Hak
    • Journal of the Korean Society for Quality Management
    • /
    • v.35 no.4
    • /
    • pp.140-146
    • /
    • 2007
  • In this paper, we consider a periodic imperfect preventive maintenance(PM) policy in which the system's failure rate after each PM remains unchanged. The system undergoes only minimal repairs at failures between PMs. Exact mathematical formula of the expected cost rate per unit time is derived. Optimal number of PMs and optimal maintenance period are derived by minimizing the expected cost rate per unit time. A numerical example is provided to illustrate the proposed approach under Weibull lifetime distribution.

A study on determining imperfect preventive maintenance intervals for the doors in Metro EMU (불완전 유지보수 모형을 통한 전동차 도어장치 예방 유지보수 주기 산정에 관한 연구)

  • Lee, Duk-Gyu;Kim, Jong-Woon;Lee, Hi-Sung
    • Proceedings of the KSR Conference
    • /
    • /
    • pp.733-741
    • /
    • 2008
  • An important problem in reliability analysis for repairable systems is to model the maintenance effect. The most of researches have assumed two extreme cases; one is perfect maintenance and the other is minimal maintenance. However, there are many cases in real situations that the maintenance effect are between both of two extreme cases. This article deals with the problem determining the imperfect preventive maintenance intervals for the doors in Metro EMU

  • PDF

Optimum Periodic Preventive Maintenance Time for a System with Imperfect Maintenance (불완전보전을 고려한 시스템의 최적 정기 예방보전 시기)

  • 정영배
    • Journal of the Society of Korea Industrial and Systems Engineering
    • /
    • v.17 no.32
    • /
    • pp.221-226
    • /
    • 1994
  • Almost preventive maintenance policies assumed that the system after pm has failure rate as before pm with probability p and as good as new with probability 1-p. This paper considers the s-expected cost of the model with imperfect periodic preventive maintenance that increasing minimal repair costs at failure and obtains the optimum periodic preventive maintenance time. Numerical example are shown in which the failure time of the system has gamma distribution.

  • PDF

A study on Determining Maintenance Intervals Considering the Maintenance Effect for the PDS in Metro EMU (전동차 승객용도어시스템의 유지보수 효과를 고려한 유지보수 주기 산정에 관한 연구)

  • Lee, Duk-Gyu;Son, Young-Jin;Lee, Hi-Sung
    • Journal of the Korean Society for Railway
    • /
    • v.14 no.3
    • /
    • pp.216-221
    • /
    • 2011
  • An important problem in reliability analysis for repairable systems is to model the maintenance effect. The most of researches have assumed two extreme cases; one is perfect maintenance and the other is minimal maintenance. However, many of maintenances performed by domestic subway operators are imperfect maintenances which have the effect between both of two extreme cases. This article deals with the problem determining the imperfect preventive maintenance intervals based on failure data in units of the PDS(passenger door system) in Metro EMU. This paper deals with a case study on determining imperfect maintenance interval by using the level of maintenance effect through reliability analysis of PDS.

Some Stochastic Properties of Imperfect Repair Model with Random Repair Time

  • Kim, Dae-Kyung;Lim, Jae-Hak
    • International Journal of Reliability and Applications
    • /
    • v.4 no.1
    • /
    • pp.27-40
    • /
    • 2003
  • Maintenance models involving minimal imperfect repair frequently appear in the literature of reliability and operations research. Most of the literatures concerning the stochastic behavior of repairable systems assume that it takes negligible time to repair a failed system and so the length of repair time does not affect the maintenance strategy. It is more realistic to consider the length of repair times in developing maintenance model, however. In this paper, we consider an imperfect repair model with random repair time and investigate some stochastic properties of the number of perfect repairs and the number of minimal repairs. Also we derive the expressions for evaluating the expected numbers of perfect and minimal repairs in general and apply these formulas for certain parametric life distributions.

  • PDF