Study And Design On Protective Device Of Intrinsically Safety Magnetic Starter

With the continuous improvement of the degree of modernization of coal mines, thereliability and safety of coal mine electrical equipment was becoming more and morestringent. According to Article454of "Coal Mine Safety Regulations", More than40kilowatts of electric motor started frequently must use electromagnetic starter. As one of theimportant coal mine electrical equipments, the performance of electromagnetic starter affectedthe safety of coal production directly. So it has a certain practical significance to design a newmagnetic starter worked more stable and reliable,protected completely,and practiced moreconveniently. In response to the existing characteristics of the magnetic starter,learned fromthe existing mature experience,studied and designed a new electromagnetic starter ofcomplete protection based on dsPIC30F6014SCM,it setted integrated protection, intelligentcontrol, communication and display as one.The main contents of this article as follows: thebasic theory of intrinsically safe circuits and the concept of pilot circuit were introduced inthe second chapter of the article; the shortcomings of intrinsically safe pilot circuit usedrelay isolation were pointed out; a new type intrinsically safe pilot circuit used optocouplerisolation was designed on the basis; the leakage protection function of the protection devicewas designed by analyzing the leakage fault; the protection principles of short circuit, phaseloss, overload, undervoltage and overvoltage of motor was proposed through the theoryanalysis of the fault of motor in the second part of the article, provided a theoretical supportfor the design of integrated protection module of motor of the protector; in the third part ofarticle,the hardware and software of the system was designed on the basis of the above; EMCdesign of the system and experiment was did in the last. The experimental results showthat: the integrated protection device of magnetic starter designed worked reliablely undervarious fault, Various functions and indicators achieved the desired objectives.