Peak duty electric machines: Design, operation and failure modes

Veysel T. Buyukdegirmenci, Philip T Krein

Research output: Chapter in Book/Report/Conference proceedingConference contribution


This paper investigates machine re-rating and design for peak duty applications. Machine thermal response under short-term overloads is explored and shown to comprise four heating modes: subtransient, transition, transient and temperature creep. In peak duty applications, the maximum temperature rise is commonly attained in the first two modes. Thermal transients in these two modes are shown to be faster than a conventional exponential characteristic. Therefore, peak duty machines are subject to severe thermal cycling. Effects of thermal cycling on machine reliability are surveyed and possible improvements are discussed. The concepts are evaluated in a hybrid electric vehicle case study. Two electric machines with similar efficiencies at their rated power levels are compared. The results show that with careful design, machine size and ratings can be substantially reduced while supporting up to 75% headroom above continuous output capability.

Original languageEnglish (US)
Title of host publicationElectrical Manufacturing and Coil Winding Expo 2010-2013
Number of pages7
StatePublished - Dec 1 2013

Publication series

NameElectrical Manufacturing and Coil Winding Expo 2010-2013

ASJC Scopus subject areas

  • Electrical and Electronic Engineering


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