Fire is one of the common disasters on our planet. This is an uncontrolled burning, evolving in time and space.

           Fire is called uncontrolled fires burning out of a special home, causing material damage. It is characterized by: formation of open flames and sparks, hot air, objects, etc., toxic combustion products and smoke, the decreased concentration of oxygen, damage to buildings and facilities, the emergence of the explosions. All this belongs to the dangerous and harmful factors affecting humans.

           Statistics of deaths showed that fire kills 40 - 50 thousand people. The number of fires, as well as the number of people killed in fires in the various countries differ greatly. For example, in the United States for every thousand people to Fires happen every year in Japan - 0.5, inChina - 0.03, while for every 1 million people at an average 25 people die in the United States per year in Japan - 19, in China - 2 [10].

           Since the beginning of the year there 4075 Fires in Donetsk region, 1991 of which occurred due to the careless Fire handling of tenants of public and private sector. And, for the above reason, because of the carelessness and the failure of basic rules of fire safety in the home only for 8 months of this year, fires killed 259 people.

           Since the beginning of the year there 4075 Fires in Donetsk region, 1991 of which occurred due to the careless Fire handling of tenants of public and private sector. And, for the above reason, because of the carelessness and the failure of basic rules of fire safety in the home only for 8 months of this year, fires killed 259 people.

           According to the Center of the promotion of GE MES of Ukraine in Donetsk region, compared to the last year the number of fires has decreased by thirty-nine cases. lifeless human bodes were found in place of fire accidents in 2008, among them - five deaths in the regional center. Losses from fires ware more than 1.7 million hryvnias, rescued wealth amounting was to more than 4 million 244 thousand hryvnia.

           Intensive growth of electricity consumption in all sectors of the economy requires constant attention to improving the fire safety of electrical installations.

           The analysis of fire protection of the facilities for various purposes shows that fire safety is largely dependent on the technical condition of electrical equipment and electrical equipment in general. Underestimation of this fact often leads to fires with the considerable material damage.

           According to the statistics from electrical fires at industrial facilities in the country as a whole represent about 28% of the total. In some cases, fires are accompanied by the death or injury of people.

           AIf the combustible materials are used in the technological processand there is a possibility of contact with air, the danger of fire or explosion may occur inside the equipment, and outside, indoors and outdoors. Thus, the most dangerous are vehicles, containers and tanks with flammable liquids, as they are not filled to the limit and an explosive mixture of steam is Formed in the space above the lignig leven. Dangerous in the Fire respect can be stations and paint shops where the Flammable liquids are used as Solvents.The cause of the explosion or fire could be the presence of combustible dust in the room and fibers.

           It is known that every fire, mainly associated with the use of electrical energy. Fire in electrical plants happens with short circuit, remedy Faiture or in the abnormal operating electrical equipment. Therefore, prediction of possible fires in the operation of equipment electric motors and the development of organizational and technical measures is a aktualserious problem.

           Analysis of fires that have occurred from damage of the electrical faults and Failure of appropriate remedies, showed: the thermal power was 52% for sub - 43% at hydropower - 5% of the total number of fires that have occurred for other reasons not related to electric current . The number of fires that occurred through the fault of electrical machinery amounted to 16%.

           These statistics lead to the conclusion of the relevance of the topic of the selected master's work.

           To develop a methodology for choosing the terms of prevention availability of combustible material (dust) on the case of asynchronous motors, operated at the technological equipment, to determine the time interval between the diagnosis of switching off the protective switching device, with the random breakage of a phase failure, which provides standardized 12.1.004-91 standard GOST fire safety (Q0 (8760) = 1 * 10-6).

            Scientific novelty of the master's work is to obtain the analytical dependence of the probability of fire during the operation of asynchronous motors of the frequency of occurrence of breakages phase conductors, the length of such a regime, the frequency of occurrence of combustible material on the case of electric motors and terms of inspections, as well as the reliability of the cut offsystem of the protective switching device, and the terms of his diagnosis.

           As a result, research in this paper has developed a mathematical model and proposed a method that can predict the probability of occurrence of fires from the operation of asynchronous motors, develop organizational and technical measures to ensure standardized GOST 12.1.004-91 level of fire safety. For case, the program for accounting, analysis and experimental data, developed at the Department «Electricity companies and towns» has been used.

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