The impact of thermal degradation on electrical machine winding insulation

Abstract

. (2015) 'The impact of thermal degradation on electrical machine winding insulation' in IEEE 10th International Symposium on Diagnostics for Electrical Machines, Power Electronics and Drives (pp: 232-238 Copyright © and Moral Rights are retained by the author(s) and/ or other copyright owners. A copy can be downloaded for personal non-commercial research or study, without prior permission or charge. This item cannot be reproduced or quoted extensively from without first obtaining permission in writing from the copyright holder(s). The content must not be changed in any way or sold commercially in any format or medium without the formal permission of the copyright holders. CURVE is the Institutional Repository for Coventry University

Thermal Degradation Phenomena of Polymer Film on Magnet Wire for Electromagnetic Coils

“…However more than three repetitions were avoided due to the significantly increased time required for every test and because the accuracy was at acceptable levels. While this particular study focuses on that of electrical breakdown measurements, the reader is also directed towards some of the authors prior literature, [7], [8], [10], [11], where the dielectric measurements of capacitance and dissipation factor have been investigated extensively.…”

“…These different factors degrade the materials simultaneously and interact with one another, for example, electrical stressing gives rise to temperature increases which in turn gives rise to both chemical and mechanical stressing occurring. Over time insulation materials may become severely degraded to the point where partial discharge occurs, leading to reduced dielectric properties and voltage resistance of the polymeric coatings [10], [11], as well as adhesion problems, delamination, surface erosion, oxidation as well as the formation of treeing and micro-cracks [3], [12]. The occurrence of repetitive partial discharge events greatly accelerates the ageing process further as it then moves from intrinsic ageing into a rapid extrinsic ageing process, which quickly leads to the catastrophic failure of the electric machine as the electromagnetic coils will quickly yield sustained shortcircuit conditions [6], [7], [8], [13], [2].…”

Degradation Control for Electric Vehicle Machines Using Nonlinear Model Predictive Control

“…Our assumption here is that degradation is entirely related to losses [40]. The assumption holds in the sense that, if energy is not employed to do useful work, it will contribute to losses, degrading the components of the machine.…”

The Investigation of Electrical Properties for Mica/Epoxy Insulation Stator Bars during the Thermal Cycle Aging Test

“…Shear stress is generated by the difference of expansion between two materials in stator bar insulation. If the connection between copper conductor and major insulation is not tight enough, layered fractures or gaps will be appeared at the interface between copper conductor and major insulation, which would results in relative movement between copper conductor and major insulation, it would damage the major insulation [2] . These layered fractures or gaps would result in partial discharge in stator bar and cause major insulation breakthrough under certain conditions.…”