# Finite Element Modeling of Eddy Currents in Uninsulated Laminated-Steel Stacks

 dc.contributor Aalto-yliopisto fi dc.contributor Aalto University en dc.contributor.advisor Belahcen, Anouar dc.contributor.advisor Rasilo, Paavo dc.contributor.author Velasco Alvarado, Jonathan dc.date.accessioned 2013-07-11T12:16:04Z dc.date.available 2013-07-11T12:16:04Z dc.date.issued 2013-05-20 dc.identifier.uri https://aaltodoc.aalto.fi/handle/123456789/10446 dc.description.abstract This thesis deals with the modeling of eddy currents in uninsulated laminations. A numerical model for the calculation of eddy current losses was implemented using finite element analysis. This model calculates the solution from the electric vector potential also known as the T-𝛺 formulation for the study of eddy current problems. The numerical model was verified by comparing the harmonic solution to different analytical models. Moreover, the results were obtained for non-linear material, i.e. electrical steel. During the manufacturing process the laminations are stacked and the uneven contact between laminations makes it impossible to assume uniformity in conductivity between adjacent laminations. Electrical conductivity degradation and surface roughness in laminated-steel increases the average iron losses. Whenever the values of inter-laminar conductivity tend to zero, the eddy current component in the direction perpendicular to the lamination vanishes. For this reason, the eddy currents will loop only within the thickness of the lamination and the losses will decrease dramatically for a certain frequency range. Assuming a linear permeability (low and high) in the inter-laminar region, and widths between 6𝜇m and 10𝜇m, causes negligible changes in the calculation of the losses for which is recommended to use wider inter-laminar areas and high permeability, as it enhances the convergence of the model. A model dealing with insulated laminated-stacks was implemented for comparison purposes. Uninsulated laminations could be used as an economical alternative for certain applications where laminated cores are used, as in the case of rotational electrical machines and transformers. en dc.format.extent 76+7 dc.format.mimetype application/pdf en dc.language.iso en en dc.title Finite Element Modeling of Eddy Currents in Uninsulated Laminated-Steel Stacks en dc.type G2 Pro gradu, diplomityö en dc.contributor.school Sähkötekniikan korkeakoulu fi dc.contributor.department Department of Electrical Engineering en dc.subject.keyword Computational Electromagnetics en dc.subject.keyword Finite Element Analysis en dc.subject.keyword Electrical Machines en dc.subject.keyword Iron Losses en dc.subject.keyword Eddy Currents en dc.subject.keyword Steel Laminations en dc.identifier.urn URN:NBN:fi:aalto-201307127191 dc.programme.major Electromechanics en dc.programme.mcode S-17 fi dc.type.ontasot Diplomityö fi dc.type.ontasot Master's thesis en dc.contributor.supervisor Arkkio, Antero dc.programme EST - Master’s Programme in Electrical Engineering fi dc.location P1 fi
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