Kolosyuk A. Improving intrinsic safety measures under inductive load pulse power supply of mining equipment

The thesis deals with solving an important scientific task of increasing intrinsic safety of electric equipment used in gassy and dusty mines. Analysis of certain papers is made, showing prospects of using switching power supply to increase intrinsic safety of mining electric equipment. The structure of two systems of intrinsically safe switching power supply in case of single-phase and two-phase rectification of alternating current. The methodology of determining current intensity and capacity in systems of switching power supply is developed, necessary to evaluate intrinsic safety. Conditions of applying developed intrinsically safe systems are ascertained. A new way and two means of securing intrinsic safety for lines supplying inductive loads based on switching power transmission from the source to the load are developed. Igniting currents of a methane-air explosive mixture of the developed systems of switching power supply are experimentally determined, and it is shown that they are higher than in case of direct current supply, which ensures intrinsic safety increase. A normative document is substantiated based on results of the research per-formed, which regulates technical requirements and test methods for switching systems of intrinsically safe power supply of mine units controlling explosion proof equipment automatic devices. Examples are given of using intrinsically safe circuits of switching power supply.