Krzysztof Lesiak

The article presents and discusses the results of research on hazard, especially temperature, for selected lithium-ion-phosphate cells operated in accordance with the manufacturer’s recommendations but used under onerous mining conditions. This applies to the performance of cells in battery sets without the application of any management system (BMS). On the basis of the obtained test results, first of all, the influence of the value of the charging current of cells and the ambient temperature for both free and deteriorated heat exchange, appropriate conclusions and practical recommendations were formulated. This applies especially to threats in the case of random, cyclic, minor overloading, and discharging of the cells.

A method for selecting dynamic parameters and structures of drive systems using the synthesis algorithm is presented. The dynamic parameters of the system with six degrees of freedom, consisting of a power component (motor) and a two-speed gearbox, were determined, based on a formalized methodology. The required gearbox is to work in specific resonance zones, i.e., meet the required dynamic properties such as the required resonance frequencies. In the result of the tests, a series of parameters of the drive system, defining the required dynamic properties such as the resonance and anti-resonance frequencies were recorded. Mass moments of inertia of the wheels and elastic components, contained in the required structure of the driving system, were determined for the selected parameters obtained during the synthesis.

Tests of flame-proof properties of supply-control box for a floor-loader operating in underground mine workings, where methane and/or flammable dust explosion hazard occurs are presented. The tests included, among others, a determination of the explosion pressure, the enclosure strength to the pressure and the test of non-transfer of internal explosion. The tests enabled to localized the components, which required some improvements regarding their mechanical strength but also confirmed safety of the final design. The enclosure of the supply-control equipment of a floor-loader is designed within the HYDKOM 75 project co-financed by the National Centre for Research and Development.

A requirement to limit the temperature of diesel engine components results from the recommendations of the drive manufacturers as well as from the mining regulations. In order to meet these requirements it is necessary to reduce the temperature of the exhaust gases below 150 °C and in order to achieve this objective, in the exhaust system of the diesel engine various types of heat exchangers are used. The article presents the procedures and results of testing the pressure free heat exchanger for cooling the exhaust systems in underground mining machinery drives applied in hard coal mines.