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.read more
Citations
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Journal ArticleDOI
A 380-12 V, 1-kW, 1-MHz Converter Using a Miniaturized Split-Phase, Fractional-Turn Planar Transformer
TL;DR: In this paper, a miniaturized split-phase half-turn transformer is demonstrated, which leverages the well-established parallelization benefit of employing multiple phases, as in a matrix transformer, with the dramatic reduction in copper loss associated with the relatively new Variable Inverter/Rectifier Transformer (VIRT) architecture.
Journal ArticleDOI
Thermal Effects on Inductor Winding Resistance at High Frequencies
TL;DR: In this article, the effect of temperature on an inductor's winding resistance at low and high frequencies was analyzed and its nonlinear dependence on the overall temperature of the foil winding is compared with that of winding dc resistance.
Proceedings ArticleDOI
Analytical method for generalization of numerically optimized inductor winding shapes
J. Hu,Charles R. Sullivan +1 more
TL;DR: In this article, a method is developed to use a single set of two-dimensional numerical optimizations of inductor winding shapes to simply calculate the optimal winding configuration for any design on the same core without repeating the computationally intensive numerical optimization.
Proceedings ArticleDOI
Rotary Transformer Design for Brushless Electrically Excited Synchronous Machines
H. Krupp,Axel Mertens +1 more
TL;DR: In this paper, a contactless energy transfer system to replace the slip-ring system in an electrical machine is discussed, where the focus is laid on the power transferring device, a rotary transformer, and an analytical model for winding losses is created.
Journal ArticleDOI
Magnetic vector potential based model for eddy-current loss calculation in round-wire planar windings
TL;DR: In this article, an analytical development of the magnetic vector potential is used to investigate the losses in round-wire planar windings, where the current distribution in wires is affected by the skin effect and the field created by adjacent wires, resulting in a closed-form problem.
References
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Journal ArticleDOI
Effective resistance to alternating currents of multilayer windings
Edward Bennett,Sidney C. Larson +1 more
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
Effective Resistance to Alternating Currents of Multilayer Windings
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.