Introducing physics of failure considerations in the electrical machines design

Madonna, Vincenzo; Giangrande, Paolo; Galea, Michael

Abstract

For continuous-duty applications, electric motors are conventionally designed to experience a hot-spot temperature below their insulation thermal class. When frequent overloads are required, a safety temperature-margin is considered at the machine's design stage, so that the insulation is not thermally overstressed. This procedure leads to an increment of the machine's size, with a consequent power density reduction. Indeed, lower thermal loadings are obtained by decreasing the winding current density by e.g. increasing the equivalent cross-sectional area of conductors. For some applications, it is possible to avoid the “over-engineering”, but the reliability level might be compromised. This work addresses the subject of thermal overload capability in electrical machines, combining elements of thermal analysis, reliability and physics of failure. A novel design methodology is introduced and validated by means of thermal accelerated lifetime tests on winding specimens. The proposed approach is used for redesigning a brushless DC motor achieving excellent results in terms of power density boost.

Citation

Madonna, V., Giangrande, P., & Galea, M. (2019). Introducing physics of failure considerations in the electrical machines design. . https://doi.org/10.1109/IEMDC.2019.8785304

• Conference Name: 2019 IEEE International Electric Machines & Drives Conference (IEMDC)
• Conference Location: San Diego, California, USA
• Start Date: May 12, 2019
• End Date: May 15, 2019
• Acceptance Date: Feb 17, 2019
• Online Publication Date: Aug 5, 2019
• Publication Date: 2019-05
• Deposit Date: Aug 16, 2019
• Publicly Available Date: Aug 19, 2019
• Pages: 2233-2238
• ISBN: 978-1-5386-9351-3
• DOI: https://doi.org/10.1109/IEMDC.2019.8785304
• Public URL: https://nottingham-repository.worktribe.com/output/2441972
• Publisher URL: https://ieeexplore.ieee.org/abstract/document/8785304
• Additional Information: © 2019 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, 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 component of this work in other works.