| Author: | Zhang, Weilin |
| Title: | Reliability studies of onboard train electronic components with focus in different kinds of capacitors |
| Degree: | M.Sc. |
| Year: | 2012 |
| Subject: | Capacitors. Reliability (Engineering) Railroads -- Trains -- Maintenance and repair. Hong Kong Polytechnic University -- Dissertations |
| Department: | Department of Electronic and Information Engineering |
| Pages: | xi, 113 leaves : ill. ; 30 cm. |
| Language: | English |
| Abstract: | Tantalum electrolytic capacitors, aluminum electrolytic capacitors and multilayer ceramic capacitors are three main kinds of capacitors used in the door system of MTR. The objective of studying the reliability of them is to replace the components preemptively in time prior to an actual failure and provide recommendation of maintenance in order to keep the railway to reliably operate in an extended period of time from the angle of capacitors. Reliability research of capacitors is to firstly analyze the failure mode and reasons from the inherent characteristics of capacitors; and then conduct reliability tests to discover the quantitative impact of environmental or operating factors on the capacitors; in the end, give an estimated lifetime to provide reference for others people. Tantalum electrolytic capacitors, aluminum electrolytic capacitors and multilayer ceramic capacitors have different structures, characteristics and performances. Therefore, failure analysis would be carried on respectively, which includes failure modes and the reasons for every failure mode. And then the cautions in use and measures to prevent the failure are given. The life test is the basic reliability test method to assess the various reliability characteristics of the product under normal operating conditions. And accelerated life test with higher stress which makes the failure appear quickly is an appropriate method, particularly for long-lived capacitors. Bases on the models of accelerated life test, lifetime of capacitors could be estimated. Methods comparison of lifetime estimation for tantalum electrolytic capacitors and MTTF calculation for aluminum electrolytic capacitors and multilayer ceramic capacitors are carried out. Besides, given the special environment in the MTR, the impact of humidity and vibration are also analyzed. |
| Rights: | All rights reserved |
| Access: | restricted access |
Files in This Item:
| File | Description | Size | Format | |
|---|---|---|---|---|
| b25315638.pdf | For All Users (off-campus access for PolyU Staff & Students only) | 2.15 MB | Adobe PDF | View/Open |
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