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
Simple resistance calculation in litz-wire planar windings for induction cooking appliances
TL;DR: In this paper, the authors present a simple method to calculate the winding resistance of a litz-wire inductor in an induction cooking appliance, taking into account eddy-current losses, including conduction losses and proximity effect losses.
Journal ArticleDOI
Frequency-domain homogenization of bundles of wires in 2-D magnetodynamic FE calculations
Johan Gyselinck,Patrick Dular +1 more
TL;DR: In this article, a general approach for the frequency-domain homogenization of multiturn windings in two-dimensional (2-D) finite element calculations is presented, where a skin and proximity effect characterization of the individual conductors, of arbitrary cross-section and packing, is obtained using a representative 2-D FE model.
Proceedings ArticleDOI
Modelling iron-powder inductors at high frequencies
TL;DR: In this paper, a high-frequency model of iron-powder core inductors is studied and the first self-resonant frequency is determined from the plot of the measured reactance and allows for the calculation of the parasitic capacitance.
Proceedings ArticleDOI
Calculating the short-circuit impedances of a multiwinding transformer from its geometry
V.A. Niemela,G.R. Skutt,A.M. Urling,Y.-N. Chang,Thomas G. Wilson,Harry A. Owen,Ronald C. Wong +6 more
TL;DR: In this paper, the authors derived analytical expressions for the leakage inductance between all pairs of transformer windings, expressions which depend only on the winding geometry and the frequency of excitation.
Proceedings ArticleDOI
Transposition effects on bundle proximity losses in high-speed PM machines
TL;DR: In this article, the effects of transposition of the insulated strands in stator winding bundles on the copper losses in high-speed machines were investigated, and it was shown that the bundle proximity losses must be considered in the design of stator windings for high speed machines, and the amplitude of these losses decreases monotonically as the level of Transposition is increased from untransposed to fully-transposed (360°) wire bundles.
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.