Helical retaining sleeve for eddy current loss reduction in high-speed SPM machine

Mahir Al-ani, Simon Barrans

Research output: Contribution to journalArticlepeer-review


A rotor retaining sleeve is mechanically necessary in the structure of high-speed SPM machines to prevent structural failure. However, the significant eddy current loss within metal sleeves leads to a reduction in electro-magnetic efficiency and serious thermal and mechanical issues. Therefore, several techniques and methods have been proposed and developed to reduce such losses. In this paper, a helical retaining sleeve is proposed to reduce losses by cutting the flow path of the eddy currents. Using FEA, a comparison is made of the electromagnetic and mechanical performance of the proposed sleeve against a conventional sleeve having the same material and dimensions. It is concluded that the eddy-current loss reduces significantly when the helical sleeve is used, whereas the mechanical stress is broadly unchanged in the central region of the rotor with only a small increase around the ends when compared with the conventional sleeve.
Original languageEnglish
Pages (from-to)2087-2092
Number of pages6
JournalElectrical Engineering
Issue number4
Early online date3 Feb 2021
Publication statusPublished - 1 Aug 2021


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