Analysis of Single Coil PM-BLDC

The aim of the paper is FEM analysis of single coil BLDC motor operated as drive of small piston pump. The paper contains analysis of design, distribution of magnetic field, forces and torque under static and dynamic conditions. Voltages, currents, signals waveforms are also given as the results of analysis. The cogging torque and total torque are discussed in the paper

Thermal analysis of 8.5 MVA disk-type power transformer cooled by biodegradable ester oil working in ONAN mode by using advanced EMAG–CFD–CFD coupling

Power transformers are the first devices used to transfer the electrical energy produced in power plants to the grid to supply the industrial and individual receivers with electricity. The heat generation in windings and core, being an effect of the power losses, is usually dissipated in large units by using mineral oils, which are harmful to the environment. Nowadays, the industry and global society seek environmentally-friendly alternatives. One of the most promising substitute for their high biodegradability, safety in operation, and favourable thermo-physical properties are natural ester oils. For this reason, a numerical study of 8.5 MVA disk-type power transformer cooled using conventional mineral oil and a commercially used rapeseed ester oil is presented in this paper. Moreover, due to different thermal behaviour of the considered oils, the comparison was made for the unit working in different seasons of hot and moderate climate zones (Argentina and Poland). In the numerical approach, electromagnetic (EMAG) and computational fluid dynamics (CFD) models were used for a detailed study of the selected device. In particular, a novel and very efficient EMAG–CFD–CFD coupling procedure was developed to assess the cooling of the large power transformer. Such a coupled computational procedure allowed for the detailed investigation of the power loss, oil flow characteristics, and temperatures with a satisfying computational effort. The results showed that the average windings temperatures are higher by 2–9 K when the ester oil is used, dependent on the ambient conditions. The hotspot temperature in the low voltage windings increased by up to 9 K and up to 18 K in the high voltage windings using ester oil. According to the results, the oil duct construction requires modification in the high voltage region for transformers cooled using mineral oil in cold climate conditions.Fil: Stebel, Michal. Silesian University Of Technology; PoloniaFil: Kubiczek, Krzysztof. Silesian University Of Technology; PoloniaFil: Rios Rodriguez, Gustavo Adolfo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Palacz, Michal. Silesian University Of Technology; PoloniaFil: Garelli, Luciano. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Melka, Bartlomiej. Silesian University Of Technology; PoloniaFil: Haida, Michal. Silesian University Of Technology; PoloniaFil: Bodys, Jakub. Silesian University Of Technology; PoloniaFil: Nowak, Andrzej J.. Silesian University Of Technology; PoloniaFil: Lasek, Pawel. Silesian University Of Technology; PoloniaFil: Stepien, Mariusz. Silesian University Of Technology; PoloniaFil: Pessolani, Francisco. Tadeo Czerweny S.a.; ArgentinaFil: Amadei, Mauro. Tadeo Czerweny S.a.; ArgentinaFil: Granata, Daniel. Tadeo Czerweny S.a.; ArgentinaFil: Storti, Mario Alberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe. Centro de Investigaciones en Métodos Computacionales. Universidad Nacional del Litoral. Centro de Investigaciones en Métodos Computacionales; ArgentinaFil: Smolka, Jacek. Silesian University Of Technology; Poloni

Development, Analysis and Experimental Investigation of Superconducting Wireless Power Transfer System Operating in Kilohertz Range

International audienc

Development, Analysis and Experimental Investigation of Superconducting Wireless Power Transfer System Operating in Kilohertz Range

International audienc

Termodynamické vlastnosti a teplota skelného přechodu u praženého a nepraženého karobového prášku

Moisture adsorption isotherms of unroasted and roasted carob powder (Ceratonia siliqua L.) at 15, 25, and 40 °C were determinated by the static gravimetric method over the wide range of water activity from 0.06 to 0.90. GAB model fitted well the experimental adsorption data showing sigmoid shape curves for both samples. Claussius-Clapeyron equation showed that the adsorbed moisture is strongly bound to the surface of unroasted carob powder in low moisture content than that in roasted sample. The variation of the net integral enthalpy and entropy with the moisture content exhibited maximal and minimal values for unroasted carob powder at low moisture content, respectively. Combining the glass transition temperature lines with adsorption isotherms, it was found that roasted carob powder is stable up to 0.43 aw in comparison with unroasted carob powder (up to 0.38 aw). Additionally, higher content of phenolics was observed in roasted carob powder.Vlhké adsorpční izotermy nepraženého a pražené karobového prášku (Ceratonia siliqua L.) při 15, 25 a 40 ° C byly stanoveny statickou gravimetrickou metodou v širokém rozmezí aktivity vody od 0,06 do 0,90. GAB model dobře vyhovoval experimentálním adsorpčním datům ukazujícím sigmoidní křivky tvaru pro oba vzorky. Claussius-Clapeyronova rovnice ukázala, že adsorbovaná vlhkost je silně vázána na povrch nepraženého práškového rohovky v nízkém obsahu vlhkosti než v praženém vzorku. Variace čisté integrální entalpie a entropie s obsahem vlhkosti vykazovaly maximální a minimální hodnoty pro nepražený prášek z rohovky při nízkém obsahu vlhkosti. Kombinace teplotních linií skelného přechodu s adsorpčními izotermami bylo zjištěno, že pražený prášek z rohovníku je stabilní do 0,43 aw ve srovnání s nepraženým rohovkovým práškem (až do 0,38 aw). Kromě toho byl v pražené karobovém prášku pozorován vyšší obsah fenolů