Research On Breaking Arc Characteristics Of Bridge-type Contact

Contactor is an important kind of electronic component, also it has the advantagesof high sensitivity and low power consumption. At the same time, as the advancing intechnology and the pursuit of the performance of the product excellence, the demand ofcontactor’s voltage and current has become higher and higher, now the high voltagehigh power DC contactor is in the ascendant, so it is very necessary to lucubrate thereliability and longevity of high voltage high power DC contactor. While the contactsare disconnecting there is an arc, which will cause erosion on the surface of the contactsby high temperature function, and further cause the problems of material loss andinvalid contact, so this is the decisive factor of longevity and breaking capacity. So thispaper sets about the aspects of arc characteristics, and further analyses the idealenvironment for the contactor by researching the influence of the arc.This paper comprehensively analyses the research state throughout the world, andfirst overall designs the structure of arc experimental system. We manufacture half amock-up of high voltage high power bridge-type contacts DC contactor, which cansimulate the actual working procession of contactors, and provides an experimentalplatform for theory study. Then this paper accurately measures the various technicalindicators of it, including the static parameters and dynamic parameters. Then this paperdesigns peripheral equipment for it, including load and gas circuit, etc.Secondly, by designing the hardware and software system, this paper manufacturesan experimental electronic control system. The hardware system consists of main testingloop, triggering and driving unit, coil driving unit, signal conditioning unit andsynchronous signal acquisition and analysis unit. The lower computer system consists ofthe main controlling program, data acquisition program and timing parameterscalculation program. The upper computer system consists of disjunction and closingcontrol module, data acquisition and procession module and arc images processionmodule. Finally this paper displays the relevant software interfaces and tests thesoftware system.For the arc experiments, this paper provides applicable methods of experiment andanalysis. For there are too many factors to be analyzed, this paper designs the contentsof experiment by DOE, in order to greatly reduce the experiment times and improveefficiency. Then this paper gives the calculation and extraction methods of arcparameters. Then according to arc image data, we design image preprocessing algorithmto filter out noise factors. Finally this paper introduces the image target sub-pixellocation technology, by which improving the data processing precision at5~10times.Finally, this paper thoroughly analyses the high voltage high power DC bridge-typed contacts breaking arc. We carry out the research work on low power levelDC arcs in advance, respectively select hectowatt (300W) and kilowatt (2.5kW) DCarcing experiments. Then this paper thoroughly analyses the influence of breaking speed,contact area, magnetic field strength, gas environment, environment pressure andvacuum environment, etc. on arc, then summarizes the arc characters under idealenvironment, also lists and analyses five common abnormal conditions during arcing.The research achievements of this paper provide contact systems designing basis ofhigh power relay and contactor for the electrical designing personnel.