Research On Fault Analysis And Application Strategy Of Relays And Contactors Of EMUs

With the rapid development of the domestic high-speed railway business,the use of EMUs has become more and more extensive.How to improve the availability of EMUs,ensure the order of railway transportation,and improve the quality of passenger service has become an important topic.Various electromagnetic relays and contactors are widely used in various functional systems on the EMU to achieve logic control,low-power load connection,weak current control,strong current control,signal transmission,safety monitoring and protection,etc.They cooperates with the microcomputer control unit to realize the intelligent control of the EMU.However,because traditional electromagnetic relays and contactors are susceptible to environmental factors,and the use of mechanical contacts causes the service life to be limited.As a result,relays and contactors failures occur from time to time during the operation of the EMU.It becomes a major factor leading to the failure of the EMU,and affected the reliability of EMU operation.This article mainly focuses on the electromagnetic relay and contactor faults of CRH3 series EMUs and CR400 BF platform EMUs,and analyzes the main reasons for the failure of relays and contactors.Reasons for failure include include: coil open circuit,contact bridge falling off,contact deformation,contactor electronics Module failures,etc.Combined with the actual situation of the EMU on-site application,propose corresponding solutions,and good results were achieved.At the same time,this article found through statistics,when disassembling and inspecting the relays and contactors which replaced due to the failure of the EMU,there are not many devices that can confirm the point of failure.In this regard,research on the contact oxidation of relays and contactors,and the compatibility of EMU network systems,corresponding optimization suggestions were put forward.Through the analysis of CR400 BF type EMU door opening and closing relay,high and low speed fan contactor fault conditions,the potential impact of the dust environment of the electrical cabinet on the working status of the relay contactor is proposed and analyzed,and the difference in the sealing structure of the electrical cabinet of different types of EMUs is compared.And propose corresponding solutions.Finally,by analyzing the failures and causes of the CR400 BF type EMU door closing circuit and the main circuit breaker enabling circuit,the optimization suggestions are put forward for the way the relay participates in the circuit function control to reduce the failure rate of the related circuits.