Analyzation And Experimental Study On Contact Bounce Based On Contacts Dynamic Contact Pressure

Contact bounce is a serious impact on the performance of contact system.The ablation of the arc will also reduce the electrical life of the contactor.The Break-Connection of the contact or contact bridge bounce was treated as contact bounce in previous technology,which was not strict.The contacts dynamic contact pressure signal can be used to study the comprehensive contact bounce.But the patents and early testing technologies aimed at the testing of static initial and final pressure,and the sensor which can be directly used for the contacts dynamic contact pressure measurement was hard to find.Referring to the electrical theory and sensor technology,this paper put forward a testing method using polyvinylidene fluoride(PVDF)piezoelectric film for the contacts dynamic contact pressure.The relationship between the contact bounce and the Break-Connection of the contact was studied under the principle of elastic wave,as well as th e relationship between the contact bounce and closing phase Angle.The main achievements are as follows:The relationship between the contact bounce and dynamic contact pressure was studied,and the time-history of the contact bounce and dynamic contact pressure were determined with the application of elastic mechanics.The changing of the dynamic contact pressure along with the contact bounce was studied.This study laid a theoretical foundation for the study of the contact bounce using dynamic contact pressure signal.The contact vibration and swing in the moving process were analyzed with high speed camera.In order to analyze the contact bounce when the contactor closed,especially the status of no dangerous vibration phase,the characteristics of the swing(twisting)and vibration when the contacts moved were found out.A contacts dynamic contact pressure sensor was made,whose sensitive element was polyvinylidene fluoride(PVDF)piezoelectric film.Referring to theoretical analysis of the structure characteristics,stress and strain of the contact system,a direct method and a elastic wave method were proposed to obtain the contacts dynamic contact pressure signal.The advantages and disadvantages of the two methods were compared.The best test point of the elastic wave method was found based on the distribution of the stress and strain of the static contact system.A quasi static calibration technique of the contacts dynamic contact pressure sensor based on pendulum-typed metal ball impact method was introduced in this paper.The relationship of the dynamic contact pressure and output voltage of the sensor was provided.The hardware and software of the AC contactor dynamic characteristics testing system was studied.With this system the contacts dynamic contact pressure,the core displacement,contact bounce,excitation voltage and exciting current signal can be test clearly and accurately.A coupling simulation with machine,electric,magnetic on the contactor has been realized with the software ADAMS,which provides a theoretical reference to the experimental study of dynamic contact pressure.The existing error of the contact bounce test was pointed out.The contact bounce was studied using the contacts dynamic contact pressure signal.The relationship between the contact bounce of the two pairs of contacts on the same bridge and the Break-Connection of the contact,the contact bounce and the closing phase Angle were studied.Compared with the previous method of contact bounce measuring,a more comprehensive and detailed information can be gotten using contacts dynamic contact pressure signal,which provides a useful reference to optimum design of contactors.