Numerical and Analytical Study of an Electric Motor Cooling System
DOI:
https://doi.org/10.5433/1679-0375.2026.v47.53878Keywords:
electric motor, air cooling, Analytical, computational fluid dynamics, heat transferAbstract
The growing demand for efficiency, decarbonization, and sustainability has placed electric motors at the forefront of industrial innovation, driving the need for high performance with minimal size and enhanced energy efficiency. Since motors lose energy mainly as heat through Joule losses in the stator and rotor, effective cooling is essential to achieve higher power density without compromising performance. This study investigated heat transfer in IC511 motors with tube cooling systems using analytical and numerical approaches. The analytical study showed that higher airflow speeds consistently improve cooling, with fan type and rotational speed having the greatest impact, while tube length, diameter, and operating temperatures were less influential. Numerical simulations revealed that front deflectors reduced heat transfer by 21%, the use of Variable Speed Drive operation at low speeds decreased it by 15% to 71%, and smaller fans caused a 26% reduction, whereas end shield modifications improved cooling by approximately 6%, and removing up to 24 tubes maintained heat removal, suggesting cost-saving potential. Overall, the study advances understanding of thermal behavior in tube-cooled motors and identifies critical design parameters to optimize performance and sustainability.
Downloads
References
Abeykoon, C. (2020). Compact heat exchangers – Design and optimization with CFD. International Journal of Heat and Mass Transfer, 146, 118766. https://doi.org/10.1016/j.ijheatmasstransfer.2019.118766
Ahmed, F., Roy, P., Towhidi, M., Feng, G., & Kar, N. C. (2019). CFD and LPTN hybrid technique to determine convection coefficient in end-winding of TEFC induction motor with copper rotor. In Proceedings of the 45th Annual Conference of the IEEE Industrial Electronics Society (IECON 2019), Lisbon, Portugal. https://doi.org/10.1109/IECON.2019.8926651
ANSYS. (2021a). Ansys CFX-Solver Modeling Guide (Release 2021 R2). Ansys.
ANSYS. (2021b). Ansys CFX-Solver Theory Guide (Version 2021 R2). Ansys. https://dl.cfdexperts.net/cfd_resources/Ansys_Documentation/CFX/Ansys_CFX-Solver_Theory_Guide.pdf
Azeez, A. A., Olusegun, O., & Dare, S. (2024). Increase in performance efficiency of a heat exchanger through construction modification. International Journal of Research Publication and Reviews, 5(5), 3271–3279. https://doi.org/10.55248/gengpi.5.0524.1221
Bergman, T. L., Lavine, A. S., Incropera, F. P., & DeWitt, D. P. (2011). Fundamentals of Heat and Mass Transfer (7th ed.). John Wiley & Sons.
de Paula Ferreira, A. (2013). Sizing of heat exchangers air-to-air in three-phase induction electric motors (Master’s thesis, Faculdade de Engenharia da Universidade do Porto).
Eletrobrás, Procel, Instituto Euvaldo Lodi, & Confederação Nacional da Indústria. (2009). Motor elétrico: guia básico. https://arquivos.portaldaindustria.com.br/app/conteudo_18/2014/04/22/6281/Motor_eletrico.pdf
Gronwald, P.-O., & Kern, T. A. (2021). Traction motor cooling systems: A literature review and comparative study. IEEE Transactions on Transportation Electrification, 7(4), 2892–2913. https://doi.org/10.1109/TTE.2021.3075844
International Electrotechnical Commission (IEC). (2020). IEC 60034-6: Rotating electrical machines – Methods of cooling (IC Code). https://www.iec.ch
International Energy Agency. (2021). World Energy Outlook 2021. IEA. https://www.iea.org/reports/world-energy-outlook-2021
Liu, J., & Ai, M. (2022). Structural optimization design and heat transfer characteristics of air-to-air cooled high voltage motor heat exchanger. Case Studies in Thermal Engineering, 40, 102532. https://doi.org/10.1016/j.csite.2022.102532
Louw, F. G., Backström, T. V., & Spuy, S. V. D. (2014). Investigation of the flow field in the vicinity of an axial flow fan during low flow rates. In Proceedings of ASME Turbo Expo 2014: Turbine Technical Conference and Exposition, Düsseldorf, Germany. https://doi.org/10.1115/GT2014-25927
Munson, B. R., Okiishi, T. H., Huebsch, W. W., & Rothmayer, A. P. (2012). Fundamentals of Fluid Mechanics (7th ed.). Wiley.
Nailen, R. L. (1975). Understanding the TEWAC motor. IEEE Transactions on Industry Applications, IA-11(4), 350–355. https://doi.org/10.1109/TIA.1975.349307
NASA Glenn Research Center. (2021). Examining spatial (grid) convergence. https://www.grc.nasa.gov/www/wind/valid/tutorial/spatconv.html
Raman, R., Dewang, Y., & Raghuwanshi, J. (2018). A review on applications of computational fluid dynamics. International Journal of LNCT, 2(6), 1–7. https://www.ijlnct.org/paper-directory/volume-2/issue-6/6.pdf
Soler & Palau Ventilation Group. (2025). Catálogo de ventiladores axiais AVR (J) [Código: AVR-042_2025-J]. https://solerpalau.com.br/biblioteca/produto/043/AVR-042_2025-J.pdf
Stockton, C. A., McElveen, R. F., & Chastain, E. (2024). The integral role of electric motors in achieving sustainability. IEEE Transactions on Industry Applications, 60(5), 7949–7957. https://doi.org/10.1109/TIA.2024.3408721
Sung, S.-C., Kim, S.-K., & Oh, M.-D. (2021). Numerical analysis of the cooling performance of a totally enclosed air-to-air cooled motor using a dual cell heat exchanger model. Journal of Mechanical Science and Technology, 35(6), 2719–2731. https://doi.org/10.1007/s12206-021-0542-z
Tan, C., Yap, W., Cheah, J., Yi Tien, E. W., Huey, J., Didane, D., Manshoor, B., & Elshayeb, S. (2024). CFD simulation and analysis of a fin and tube heat exchanger: Impact of air mass flow rate on thermal performance. Journal of Design for Sustainable and Environment, 6(2), 14–22.
Trivellato, F., & Raciti Castelli, M. (2015). Appraisal of Strouhal number in wind turbine engineering. Renewable and Sustainable Energy Reviews, 49, 795–804. https://doi.org/10.1016/j.rser.2015.04.127
Wang, X., Li, B., Gerada, D., Huang, K., Stone, I., Worrall, S., & Yan, Y. (2022). A critical review on thermal management technologies for motors in electric cars. Applied Thermal Engineering, 201, 117758. https://doi.org/10.1016/j.applthermaleng.2021.117758
WEG S.A. (2024). Guia de especificação de motores elétricos. https://static.weg.net/medias/downloadcenter/h32/hc5/WEG-motores-eletricos-guia-de-especificacao-50032749-brochure-portuguese-web.pdf
White, F. M. (2006). Viscous Fluid Flow (3rd ed.). McGraw-Hill.
Wierda, L., & Zanutthi, A. (2024). Ecodesign Impact Accounting Overview Report 2024. https://www.vhk.nl/downloads/Reports/EIA/2024%20EIA%20IV%20Overview%20Report.pdf
Wilcox, D. C. (2006). Turbulence Modeling for CFD (3rd ed.). DCW Industries.
Yu, X., & Meng, D. (2018). Design analysis and improvement of cooler in positive-pressure explosion-proof low-speed high-capacity induction motors. Applied Thermal Engineering, 129, 1002–1009. https://doi.org/10.1016/j.applthermaleng.2017.10.101
Downloads
Published
How to Cite
Issue
Section
License
Copyright (c) 2026 Miguel Costa, Alexandre M Afonso
This work is licensed under a Creative Commons Attribution-NonCommercial 4.0 International License.
The Copyright Declaration for articles published in this journal is the author's right. Since manuscripts are published in an open access Journal, they are free to use, with their own attributions, in educational and non-commercial applications. The Journal has the right to make, in the original document, changes regarding linguistic norms, orthography, and grammar, with the purpose of ensuring the standard norms of the language and the credibility of the Journal. It will, however, respect the writing style of the authors. When necessary, conceptual changes, corrections, or suggestions will be forwarded to the authors. In such cases, the manuscript shall be subjected to a new evaluation after revision. Responsibility for the opinions expressed in the manuscripts lies entirely with the authors.
This journal is licensed with a license Creative Commons Attribution-NonCommercial 4.0 International.
