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Journal ArticleDOI

Effects of eddy currents in transformer windings

P.L. Dowell
- Vol. 113, Iss: 8, pp 1387-1394
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TLDR
In this article, the effect of eddy currents on transformer windings is considered and a method is derived for calculating the variation of winding resistance and leakage inductance with frequency for transformers with single-layer, multilayer and sectionalised windings.
Abstract
The effects of eddy currents in transformer windings are considered, and a method is derived for calculating the variation of winding resistance and leakage inductance with frequency for transformers with single-layer, multilayer and sectionalised windings. The method consists in dividing the winding into portions, calculating the d.c. resistances and d.c. leakage inductances of each of these portions, and then multiplying the d.c. values by appropriate factors to obtain the corresponding a.c. values. These a.c. values are then referred to, say, the primary winding and summed to give the total winding resistance and leakage inductance of the transformer. Formulas are derived and quoted for calculating the d.c. resistances and leakage inductances of the winding portions. Theoretical expressions are derived for the variation with frequency etc. of the factors by which the d.c. values must be multiplied to obtain the corresponding a.c. values. These expressions are presented in the form of graphs, permitting the factors to be read as required.

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Citations
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Proceedings ArticleDOI

Modeling and Calculation of the Efficiency for Low-cost Round-wire Planar Windings in Domestic Induction Heating Applications

TL;DR: In this paper, an analysis of the efficiency of round-wire planar inductors for domestic induction heating appliances is developed, which is determined by the relationship between the losses in the windings and the power dissipated by eddy currents in the vessel.
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Impact of PCB track shape on HF copper losses of planar magnetic components

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Simulation of 500 kHz High Frequency Transformer Temperature Rise under Different Wave Excitation

TL;DR: In this article, a finite element analysis method is used to build the transformer simulation model considering the correction coefficients of the high-frequency square wave, and the temperature distribution with varied frequency is shown.
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On the optimum diameter of wire for coils with fixed inductance and length

TL;DR: In this article, an analytical relation is derived for the optimum diameter of wire used for winding coils of given inductance and winding breadth, for which the ohmic loss of the coil becomes a minimum.
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Boundary Condition Independent Thermal Network Modeling of High-Frequency Power Transformers

TL;DR: In this article , a thermal network model is developed by discretizing the transformer geometry into smaller volumes and evaluating the thermal resistances by approximating the three-dimensional heat transfer problem as a piecewise one-dimensional model.
References
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Journal ArticleDOI

Effective resistance to alternating currents of multilayer windings

TL;DR: In this article, a multilayer winding carrying an alternating current, such as the windings illustrated in figures 1, 2, and 3, each layer of copper lies in the alternating magnetic field set up by the current in all the other layers.
Journal ArticleDOI

Eddy Currents in Large Slot-Wound Conductors

TL;DR: In this article, the authors discuss the more important causes of eddy currents in heavy conductors carrying alternating currents and surrounded on three sides by iron, and propose a method to identify the most important causes.
Journal ArticleDOI

Eddy-Current Losses in Cylindrical Conductors, with Special Applications to the Alternating Current Resistances of Short Coils

TL;DR: In this article, it is shown that a considerable proportion of the effective resistance of inductive coils when used at radio frequencies is caused by the eddy-currents set up in the wires of the coils by the alternating magnetic field in which they are situated, and that in extreme cases the alternating current resistance may amount to more than one hundred times the direct current resistance.
Journal ArticleDOI

Heat Losses in the Conductors of Alternating-Current Machines

TL;DR: In this article, the authors show how hyperbolic functions of complex angles may be applied to the solution of the problem of heat losses in rectangular conductors that are embedded in open slots.
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