Overview and details of the sessions of this conference. Please select a date or location to show only sessions at that day or location. Please select a single session for detailed view (with abstracts and downloads if available).
Session Chair: Shannon Sitler, GE Vernova, United States of America
Location:Egret
Session Topics:
Manufacturing (RM), Life Management & In-service Experiences (RM), Failures Cases, Investigations and Repair Procedures (RM)
Presentations
3:30pm - 4:00pm
Forming Slot Liner Insulation Materials into Electrical Machines: Manufacturing Considerations and Effects on Performance
U. Paracha1, E. Griffin1, S. Mishra1, D. Varsani2, R. McMahon1, S. Ademi1
1Warwick Manufacturing Group, University of Warwick; 2Safran Electrical and Power UK
Novel and complex stator slot geometries demand precise forming of slot liner insulation materials to ensure a reliable interface with the ground-wall insulation, thereby optimizing electrical machine performance. This paper presents a new approach to forming liner materials within the stator slot using a custom-designed, additively manufactured insertion tool. The study evaluates the impact of this approach on the electrical and mechanical properties of five distinct slot liners. Experimental validation comprises of breakdown voltage, coefficient of friction and ultimate tensile strength at room and elevated temperatures (up to 220°C), revealing minimal degradation in both insulation and mechanical properties, with only minimal failure near the creased regions. Coefficient of friction tests also demonstrate variations in interaction forces between different slot liners, stator core pack and the bespoke insertion tooling. The findings confirm the suitability and effectiveness of this forming approach for low-volume or prototype level electrical machine manufacturing.
4:00pm - 4:30pm
Overshoot and Duty Cycle Effects of Wide-Bandgap Drives on Hairpin Winding in EVs
A. Kholgh Khiz, S. Jayaram
University of Waterloo, Canada
This study investigates the turn-to-turn insulation of hairpin windings in EVs under electrical stress from wide-bandgap power converters. A custom-built SiC-MOSFET pulse generator is used to induce continuous partial discharge (PD) by applying 2.5 kV unipolar pulses with a 40 ns rise time and 5 kHz frequency to corona-resistant magnet wire samples for 24 hours. The effects of 10% and 20% overshoot; and 20% and 50% duty cycles on insulation degradation are analyzed. Diagnostic techniques, including PDIV measurement, dissipation factor analysis, and surface imaging, are used in assessing the aging effects. Results indicate that voltage overshoot significantly accelerated PDIV reduction and increased the dissipation factor, underscoring its critical role in insulation aging.
