Electrical insulation systems. Thermal evaluation of modifications to an established electrical insulation system (EIS)

2015 ◽  
2021 ◽  
Vol 18 (1) ◽  
pp. 34-42
Author(s):  
A. Leonov ◽  

Ensuring high power, efficiency and reliability of induction motor operation while providing small weight– size parameters represents an up-to-date problem. One of the factors limiting the reduction of weight–size parameters when increasing capacities of induction motors is the failure of the insulation system. Therefore, there is a strong need for studying the issues of slot fill when designing an induction motor, taking into account an increase in the heat resistance class of electrical insulation systems. The purpose of the present research is to develop a polymeric electrical insulation system of increased heat resistance for the modernization of an induction medium-capacity motor to reduce weight–size parameters and to evaluate the possible savings of winding material. The paper deals with an analysis on the stator–slot fill for the induction motor. Modern conductor and insulation materials were selected. The necessary calculations for a medium–power induction motor of different heat resistance classes were performed. The usage of the proposed electrical insulation system was substantiated. The analysis shows the possibility of increasing the heat resistance of the polymer electrical insulation systems to save winding material for induction motors without reducing the specified quality level.


2021 ◽  
Vol 13 (5) ◽  
pp. 2491
Author(s):  
Alena Tažiková ◽  
Zuzana Struková ◽  
Mária Kozlovská

This study deals with small investors’ demands on thermal insulation systems when choosing the most suitable solution for a family house. By 2050, seventy percent of current buildings, including residential buildings, are still expected to be in operation. To reach carbon neutrality, it is necessary to reduce operational energy consumption and thus reduce the related cost of building operations and the cost of the life cycle of buildings. One solution is to adapt envelopes of buildings by proper insulation solutions. To choose an optimal thermal insulation system that will reduce energy consumption of building, it is necessary to consider the environmental cost of insulation materials in addition to the construction cost of the materials. The environmental cost of a material depends on the carbon footprint from the initial origin of the material. This study presents the results of a multi-criteria decision-making analysis, where five different contractors set the evaluation criteria for selection of the optimal thermal insulation system. In their decision-making, they involved the requirements of small investors. The most common requirements were selected: the construction cost, the construction time (represented by the total man-hours), the thermal conductivity coefficient, the diffusion resistance factor, and the reaction to fire. The confidences of the criteria were then determined with the help of the pairwise comparison method. This was followed by multi-criteria decision-making using the method of index coefficients, also known as the method of basic variant. The multi-criteria decision-making included thermal insulation systems based on polystyrene, mineral wool, thermal insulation plaster, and aerogels’ nanotechnology. As a result, it was concluded that, currently, in Slovakia, small investors emphasize the cost of material and the coefficient of thermal conductivity and they do not care as much about the carbon footprint of the material manufacturing, the importance of which is mentioned in this study.


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