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A thermal improvement technique for phase windings of electrical machines

Galea, Michael; Gerada, C.; Raminosa, Tsarafidy; Wheeler, Patrick


Professor of Electrical Machines and Drives

Tsarafidy Raminosa


In electrical machines, a higher torque/force density can usually be achieved by increasing the current density in the windings. However, the resulting increase in copper losses leads to higher temperatures in the coils, especially in the centre of the slots where the thermal resistance to the ambient/cooling surfaces is highest. In this paper a novel, simple technique is presented in which a higher thermal conductivity path between the centre of the slot and the cooling arrangement is created, thus increasing the heat flow away from the slot centre. A lumped parameter thermal model is presented and used along with finite element analysis to investigate the effectiveness of the proposed technique. The lumped parameter model is also used for optimizing the high conductivity path for maximum air-gap shear stress and to obtain a compromise between the reduced slot area and the improved temperature distribution. Experimental validation is then presented to compare the predicted results with the measured results on a purposely built instrumented set-up.


Galea, M., Gerada, C., Raminosa, T., & Wheeler, P. (2012). A thermal improvement technique for phase windings of electrical machines. IEEE Transactions on Industry Applications, 48(1),

Journal Article Type Article
Acceptance Date Sep 11, 2011
Online Publication Date Nov 9, 2011
Publication Date Jan 31, 2012
Deposit Date Jul 14, 2017
Publicly Available Date Jul 14, 2017
Journal IEEE Transactions on Industry Applications
Print ISSN 0093-9994
Electronic ISSN 1939-9367
Publisher Institute of Electrical and Electronics Engineers
Peer Reviewed Peer Reviewed
Volume 48
Issue 1
Keywords Permanent magnet machines, Electrical machine windings, High current density, Thermal improvements
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Additional Information c2012 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other users, including reprinting/ republishing this material for advertising or promotional purposes, creating new collective works for resale or redistribution to servers or lists, or reuse of any copyrighted components of this work in other works


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