The Research And Application Of The Reliability Of Vibration Test Platform For Moulded Case Circuit Breaker

With the rapid development of new electrical technologies,the dependability requirements of low voltage circuit breakers and other electrical products are becoming more and more stringent.As the main electrical equipment in the distributing system,the low voltage circuit breakers are connected to and disconnected in the circuit have a decisive role.In the railway,road and navigation,strong vibration,shock and natural mechanical environment has become one of the primary factors that affect the stability and reliability of electrical equipment.Therefore,it is a great significance to carry out the vibration test and reliability research of low voltage circuit breakers.In this paper,based on the dynamic load reliability test of the moulded case circuit breaker(MCCB),a vibration testing platform based on the three-dimensional driving tensile mechanism is developed.The details of this paper are as follows.(1)Based on the "ES-60WLS3-445 shaking table" under maximum load can not make the circuit breaker static and dynamic contact separation,this paper developed mainly for moulded case circuit breaker vibration test platform.This platform adopts PLC as the controller and drives the motor through the motor driver,achieve the table X,Y,Z motion in three directions.The design method of the three-dimensional driving tensile mechanism is presented,The design of the platform including the selection of the screw,the selection of the motor and the driver,the selection of the sensor,the selection of the screw ring,the PLC control system,and the innovative design of the three-dimensional driving tensile mechanism for the low voltage circuit breaker.(2)According to different model of type I and type II installation plate,using ANSYS Workbench three-dimensional model is established according to the actual installation plate,respectively to the mounting plate I and II of the reasonable simplified model,modal analysis of mounting plate first six order natural frequency.The mode of vibration of the first six orders of the mounting plate I is within 150 Hz,and the amplitude of bending and torsional deformation is large,while the first six natural frequency of the mounting plate II is beyond 150 Hz.Moulded case circuit breaker vibration test is not easy to be excited.According to the experimental data of modal analysis,the random vibration of the installation panel I and II is analyzed.It is concluded the 3? stress of the mounting plate I is greater than the yield limit of the material,and it is easy to permanent deformation.The analysis results of the installation plate II meet the strength requirements,and it is better suited to test requirements.At the same time,the test of the plate I was carried out to validate and verify the correctness of the simulation.Using the vibration table to simulate the random vibration test of the installation board I.The simulated data are contrasted with the simulated data,and the results are in good correspond with the simulation data.(3)The dynamic model of the circuit breaker system is simplified as a cart-inverted pendulum system in the vibration environment is presented,and the fault phenomena of the circuit breaker are described by the mechanical analysis.The dynamic reliability of the molded case circuit breaker is analyzed.The simulated vibration experiment is carried out.By moving the worktable in three directions,mechanical arm reach the designated position and pulled the moving contact of the circuit breaker,and the molded case circuit breaker reached the critical test state.By applying sinusoidal excitation,determines the dynamic characteristic parameters of failure at a specific frequency and acceleration under the circuit breaker.With simulations and experiments,the theoretical model is proved to be effective when the circuit breaker is viewed as a switch in the electric system.In addition,the amplitude of the minimum sinusoidal acceleration of the circuit breaker to make the breaker have a fault phenomenon in the simulations are the same with the experiments.Therefore,it is proved that the fault property of the circuit breaker is proved to be feasible by using the dynamic model.