Use of fractional-conductor windings and semi-magnetic slot wedges in synchronous machines

• Main Authors: Christopher Donaghy-Spargo, Anthony Spargo
• Format: Article
• Language: English
• Published: Wiley 2019-05-01
• Series: The Journal of Engineering
• Subjects: machine insulation; AC machines; permanent magnet machines; air gaps; synchronous machines; machine windings; conductors (electric); magnetic flux; finite element analysis; machine performance; fractional-conductor windings; semimagnetic slot wedges; harmonic content; spatial air-gap flux density waveform; generators; motors; disadvantages briefly; example design scenario; discussion; glass-fibre type wedges
• Online Access: https://digital-library.theiet.org/content/journals/10.1049/joe.2018.8205
• ISSN: 2051-3305

This paper discusses two methods of altering the harmonic content of the spatial air-gap flux density waveform in synchronous machines (generators and motors). First, fractional-conductor windings are analysed for adoption as a replacement for a conventional distributed winding arrangement, their advantages and disadvantages briefly discussed and an example design scenario presented. Second, analysis and discussion regarding the use of semi-magnetic slot wedges as a replacement for glass-fibre type wedges is presented to complement the choice of winding in synchronous machines. Both methods are shown to benefit machine performance under certain circumstances.