Skoči na glavni sadržaj

Rezultati pretrage

eng FEM modelling and experimental validation of proximity loss
Zurek, Stan
Transformers Magazine Vol. 4, No. 1, 2017
Skin depth and proximity effects in transformer windings are important phenomena influencing the design even at power frequencies (50-60 Hz). They become critically important at elevated frequencies, especially for high-frequency transformers. This article presents results of computer simulations and experimental validation on physical prototypes. The investigated frequency range was from 1 Hz to 10 kHz.
Hrčak ID: 172548


eng Magnetic component design
Markowski, Peter
Transformers Magazine Vol. 2, No. 1, 2015
AC currents in multiple layers in the transformer window can increase copper losses significantly due to the proximity effect. Traditionally used Dowell’s curves show that the phenomenon starts at copper thickness as low as 1/5 of the skin depth which is just 1.7 mm at 60 Hz. Many designs deviate from assumptions beyond Dowell’s solution, which leads to suboptimal design. Finite Element Analysis software allows accurate modelling of high frequency phenomenon but is still considered too tedious to use and requires expert operators for accurate r...
Hrčak ID: 182934


eng SKIN – EFFECT LOSSES IN DIFFERENT LOADING CONDITIONS OF A POWER TRANSFORMER
Kelemen, Franjo; Capuder, Kosjenka; Štrac, Leonardo
Journal of Energy Vol. 61, No. 1-4, 2012
The subject of the analysis is a 300 MVA auto-connected power transformer in different loading conditions with regard to the load losses. During the electrical design time, some operating points of the transformer were analyzed in more detail using 2D electromagnetic field finite element method (FEM) software. The models included 2D magnetic stray field calculation and covered a range of transformer loading cases that covered some that are more difficult to solve with traditional analytic methods based on the static magnetic field calculat...
Hrčak ID: 198947


eng Qualitative FEM study of proximity loss reduction by various winding configurations – Part II
Zurek, Stan
Transformers Magazine Vol. 3, No. 2, 2016
Skin depth and proximity effects in transformer windings are important phenomena influencing the design even at power frequencies (50-60 Hz). However, they become critically important at elevated frequencies, especially for high-frequency transformers, operating in switched-mode power supplies for example, at any power level. This article presents a numerical study of optimum winding configurations which can drastically reduce the proximity effects. It is possible to make transformers operating even at 1 MHz without the use of very expensive Li...
Hrčak ID: 167664


eng Qualitative FEM study of proximity loss reduction by various winding configurations – Part I
Zurek, Stan
Transformers Magazine Vol. 3, No. 1, 2016
Skin depth and proximity effects in transformer windings are important phenomena influencing the design even at power frequencies (50-60 Hz). However, they become critically important at elevated frequencies, especially for high-frequency transformers, operating in switched-mode power supplies for example, at any power level. This article presents a numerical study of optimum winding configurations which can drastically reduce the proximity effects. It is possible to make transformers operating even at 1 MHz without the use of very expensive Li...
Hrčak ID: 180201


hrv ELEKTROMAGNETSKI TELEMETRIJSKI SUSTAVI - GDJE I ZAŠTO?
eng ELECTROMAGNETIC MWD/LWD - WHERE AND WHY?
Steiner, Ivo
Rudarsko-geološko-naftni zbornik Vol. 8, No. 1, 1996
Opisana je uporaba elektromagnetizma kao načina prijenosa pokazatelja od alatki na dnu bušotina do površine. To je posebno povoljno kod bušenja uz uporabu pjene, aerizirane isplake ili ispuhavanja pri bušenju u uvjetima podtlaka. Sažeto je prikazan povijesni razvitak elektromagnetizma i elektromagnetske telemetrije. Naglašen je problem slabljenja elektromagnetskih valova pri prolazu kroz stijene.
Hrčak ID: 13576