Design And Implementation Of DC Motor Idling Test Bench For Locomotives

As the core driving device of AC/DC locomotive,DC traction motor is the power source for the safe and stable operation of the locomotive.Usually,the DC traction motor locomotive will be put into use upon its production.Due to its continuous and uninterrupted operation,key components may be aged or damaged,and the motor performance index will decrease,which directly affects the safety and efficiency of locomotive operation.Therefore,the ex-factory and return tests of DC traction motors of locomotives become especially important.In order to improve the efficiency of motor overhaul test and ensure the automation of the test system,according to the requirements of locomotive DC traction motor overhaul test,this study takes ZD109 T DC traction motor test system as the research point and designs a locomotive DC traction motor idling test bench for DC traction motor idling test.Firstly,according to the specific technical requirements of locomotive DC motor idling test,the overall design of locomotive DC motor idling test stand was proposed,the three speed regulation methods of the other-excited DC motor were compared and analyzed,and the speed regulation method of reducing armature voltage was selected.Secondly,according to the rated parameters of the other-excited DC motor and the main performance index of the test bench system,the design of the main circuit of the DC motor idling test bench was completed,including the armature circuit and the excitation circuit.The armature circuit adopts three-phase semi-controlled rectification,which turns AC into DC with adjustable output voltage through phase shift trigger control.The excitation circuit adopts uncontrolled rectification,and the DC power is changed into another fixed DC power through a step-down chopper circuit.According to the test requirements and related parameters calculation,the models of rectifier components,transformers,and other components are determined and the selection of speed,temperature,voltage and current sensors for the data acquisition part of the system is completed.Then the test bench control system is designed with STM32F103VET6 as the controller and Lab VIEW as the upper computer development environment.For the control system,the design of armature circuit control,excitation circuit control and data acquisition functions were mainly complete,including hardware and software design for the minimum system module,SCR trigger module,MOS tube driver module,feedback sampling module,PID algorithm module and communication module and other parts.The upper computer interface can realize the speed control of the motor and the acquisition,display and storage of motor parameters.Finally,according to the functional requirements of the DC motor idling test bench,after verifying the performance of the control system SCR phase shifting trigger module,the on-site locomotive DC motor idling test platform was built and the locomotive DC traction motor was tested for speed regulation idling.The test results show that the designed locomotive DC motor idling test bench has a high degree of automation and the system control accuracy is within 0.5%,which realizes the functions of speed control and data acquisition of DC motor and can meet the field engineering requirements.