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Abstract

This work is a continuation and extension of previous socio-economic analyses of hard coal mines, which were conducted at the Central Mining Institute in the years 2013-2015. The paper presents the results of the economic evaluation of the hard coal mining sector in the years 2016-2018 using the Cost-Benefit Analysis (CBA) methodology. Used for the socio-economic assessment of hard coal mining, the CBA methodology enables the comprehensive evaluation of the functioning of this sector of the economy in Poland. In addition to financial aspects, which are important from the point of view of coal companies, it also included the social and environmental influence resulting from the impact of mines on the environment. Direct data of operating costs and payments (including public-law payments), incurred by the hard coal mining industry in Poland, was used. This data is obtained by Industrial Development Agency JSC, Branch Office Katowice as part of the “Program of statistical surveys of official statistics” – statistical survey “Hard coal and lignite mining industry”. They were supplemented with data coming from commonly available public statistics. For the analysed period the presented results indicate that the financial and social benefits resulting from the hard coal mining activity in Poland outweighed the financial, social and environmental costs generated by this industry. This confirms the desirability of further functioning of the hard coal mining industry in Poland, however, assuming effective restructuring activities that will result in lower costs of coal production.

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Authors and Affiliations

Piotr Krawczyk
ORCID: ORCID
Anna Śliwińska
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Abstract

In the paper, the modified (compared to the classical asymmetric half-bridge) converter for a switched reluctance machine with an asymmetric rotor magnetic circuit was analysed. An analysis for two various structures of switched reluctance motors was conducted. The rotor shaping was used to obtain required start-up torque or/and to obtain less electromagnetic torque ripple. The discussed converter gives a possibility to turn a phase off much later while reduced time of a current flows in a negative slope of inductance. The results of the research in the form of waveforms of currents, voltages and electromagnetic torque were presented. Conclusions were formulated concerning the comparison of the characteristics of SRM supplied by the classic converter and by the one supplied by the analysed converter.

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Authors and Affiliations

Piotr Bogusz
Mariusz Korkosz
Jan Prokop

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