The Impact of Thermal Degradation on Properties of Electrical Machine Winding Insulation Material

M. Sumislawska, Kostas N. Gyftakis, D. F. Kavanagh, M. McCulloch, Keith J. Burnham, D. A. Howey

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    52 Citations (Scopus)
    64 Downloads (Pure)


    Inter-turn stator short circuits can develop quickly leading to serious damage of an electric machine. However, degradation mechanisms of winding insulation material are not yet fully understood. Therefore, the main contribution of this article is analysis of the impact of thermal ageing on the electrical properties of the thin film winding insulation. The insulation samples have been aged thermally at 200–275 °C and for 100–1600 hours. After ageing, impedance spectroscopy measurements were undertaken on the samples and equivalent circuit model (ECM) parameters fitted for each measurement. This allows the impact of thermal ageing on ECM parameters to be analysed, giving insight into the changes of the electrical properties of the insulation. Finally, high voltage was applied to the samples aiming to identify the breakdown voltage characteristics of the insulation material.
    Original languageEnglish
    Pages (from-to)2951 - 2960
    Number of pages10
    JournalIEEE Transactions on Industry Applications
    Issue number4
    Early online date21 Mar 2016
    Publication statusPublished - Jul 2016

    Bibliographical note

    This article has been accepted for publication in IEEE Transactions on Industry Applications.
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    • equivalent circuit model
    • electric machine
    • impedance spectroscopy
    • polyamide-imide
    • stator winding
    • thermal degradation


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