Design Of Cable Conduction And Insulation Test System For CRH3 EMU

The cables of the CRH3 EMU control the transmission of signals and data information from various systems on the vehicle.The cable connection on the EMU is complicated,and once there is a problem,it will lead to the breakdown of the EMU,affecting driving safety,and the consequences are unpredictable.In the commissioning stage of EMU,it is necessary to test the conduction and insulation resistance of the cable,so as to find out the faults and hidden dangers as soon as possible and solve them,so as to guarantee the delivery quality of EMU.At present,most main engine manufacturers of EMU mainly use manual test method for the conduction and insulation test of cables,which has high working intensity,low efficiency and is prone to errors in the test process.In view of the above situation,this thesis designed and developed a conductive insulation test system for CRH3 EMU cable.First of all,this thesis describes the development status of cable testing technology at home and abroad,through comparative analysis of common cable testing technology at home and abroad,and combined with CRH3 EMU cable testing requirements,determine the system to test bullet train cable method.For the continuity test of CRH3 EMU cable,the two-wire system method is adopted for measurement;The insulation of cable is measured by current and voltage method.Secondly,each functional module of the system is designed according to the actual cable testing requirements.The hardware platform with STM32 as the main processor is built in this system,and the circuits of constant current source module,high voltage source module,data acquisition module and relay matrix module are designed.At the same time,the software design and development of the test unit is completed,and the functions of each module in the hardware circuit are realized.Finally,the upper computer software of the test system is developed based on the MFC class library of VS2017 platform,realizing the functions of sending operation instructions and displaying test results in real time.Considering that the actual test range of CRH3 EMU cable is large,the system adopts LoRa communication technology for data transmission,and designs wireless communication protocol and data frame structure.This thesis completed the design,development and debugging of the cable test system,and conducted the cable conduction and insulation test verification in the built test environment.Through the analysis of the testing process and results,it can be concluded that the system can improve the testing efficiency of CRH3 EMU cable and save a lot of manpower,so it has good application value.