| The life of a switchgear mainly depends on the wear of its structural parts and the wear of contacts has a great influence on the service life of the switchgear.The main form of wear of contacts is electrical wear.The electrical wear is related to arcs which are generated during the switch-on or break-off process.Under certain conditions,obvious arcs are generated during the switch-on or break-off process.The arcs not only delay the breaking time of the circuit,but also burn the contact surface.The reliability of contacts decreases due to arcs.Studying the process of arc generation and extinction can deeply explore the process of arc combustion,and achieve the effects of reducing contact arc erosion in practical applications,which has an important meaning of improving the life and reliability of contacts.In this paper,five doped AgSnO2 contact materials,Ag Sn O2/Bi2O3,Ag Sn O2/Ce O2,Ag Sn O2/La2O3,Ag Sn O2/Ti O2 and Ag Sn O2/WO3,were prepared by powder metallurgy method.Firstly,the arc time,arc energy and welding force of five kinds of contact materials were collected by JF04C electrical contact material testing system,and then the whole process of arc combustion were photographed by high-speed camera.The arc images were processed by digital image processing technology.An arc image processing method based on mathematical morphology were proposed.The arc image processing method based on mathematical morphology can not only enhance the arc images,but also detect the edge of arc images.The arc area was extracted from the arc image,and the variation of arc area during arc combustion was obtained.Then the whole arc combustion process was analyzed.The influence of different additives on arc performance was analyzed by analyzing arc time,arc energy and welding force data,and the microstructures of the tested contacts were analyzed.Combining with arc performance,arc combustion image and microstructure analysis,the performance of arc erosion resistance of five contact materials doped with different additives were determined.Among the five kinds of contact materials,the Ag Sn O2/Bi2O3 and Ag Sn O2/Ce O2 contact materials have strong arc erosion resistance. |
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