Research On The Dynamic Characteristic Of Circuit Breaker Transmission Mechanism Consider On Load Characteristics

High voltage circuit breaker have transmission mechanisms from actuator to main contacts,the dynamic characteristics of the transmission mechanism have a great influence on speed characteristics,open and close performance,and mechanical life.Therefore,the transmission mechanism is a vital part on contacting and coordinating with each part of the circuit breaker.The load resistance is the key to the dynamic characteristics of circuit breaker transmission mechanisms,it changes complexly and is difficult to measure.Therefore,it is important to study the influence of load resistance on the dynamic characteristics of the transmission mechanism.The load of main contact transmission is friction,including friction of air itinerary and contact itinerary.When move contact contacting fingers,radial deformation of contact fingers was brought out,and contact itinerary friction generated.Because of the friction between moving contact and contact fingers is difficult to measure,many scholars take it as a constant value.But in practical work,the friction between move contact and contact fingers is constantly changing.Therefore,the paper studied the influence of contact itinerary friction changes on the dynamic characteristics of the transmission mechanism of the main contacts.In order to study the friction of contact itinerary,a pitch of spring contact analysis model was established,equation of spring contact deformation and contact pressure was got based on radial stress analysis of screw spring contact micro segment.Then calculated by using Simpson numerical integration method,analyzed the relationship between rated laps and deformation of spring contact,and obtained formula of contact pressure and friction in the finally.Two kinds of load resistance curves of circuit breaker transmission mechanisms were obtained by comparing the non-linear changing frictional resistance calculated and the frictional resistance regarded as constant.Since load resistance has a comparatively large effect on the dynamic characteristics of the transmission mechanism,dynamic static analysis of main contact transmission mechanism was conducted in this paper.Then load resistances were generated into dynamic static balance equations,reaction force of each pair and driving torque in closing of main contact were obtained by using MATLAB.Subsequently,the rigid and flex hybrid mechanism model and rigid and flex hybrid with clearance mechanism model were established respectively based on the ideal mechanism.Through the simulation of the two mechanisms models respectively by ADAMS,reaction force of each pair,maximum stress and strain curves of flexible link based two kinds of load resistances were obtained.The study provides reference for the design and improvement to the circuit breaker transmission mechanisms,and it is helpful to engineering application.