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Journal ArticleDOI

Effects of eddy currents in transformer windings

P.L. Dowell
- Vol. 113, Iss: 8, pp 1387-1394
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

Validation of Inductor Analytical Loss Models under Saturation Conditions for PWM inverter

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Energy management and optimization

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Calculation of Model Based Capacitances of a Two-winding High-frequency Transformer to Predict Its Natural Resonance Frequencies

TL;DR: In this paper, an analytical approach is proposed to estimate the winding capacitances of a two/multi-winding transformer, which can be used to postulate its circuit behavior in advance of prototyping.
Proceedings ArticleDOI

Analytical minimal loss design of transformers for high frequency switch mode convertors

TL;DR: In this article, a transformer design philosophy based on fundamental principles and facilitates the design of close to optimum transformers, without significant iteration is presented, but rather an analytical procedure that accords priority to minimising losses.
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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