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This paper focuses on the improved thermal performance of electrical machines by increasing the conductor fill factor. A comparative design study of integrated starter generator (ISG) is used as a case study to investigate the mechanical, electrical and thermal aspects of pressing coils. By performing quasi-static explicit dynamic simulations, deformation of insulation has been investigated. 1.25 mm diameter magnet wires are simulated and demonstrated to be compressible up to a 0.73 fill factor without observing insulation failure. Thermal conductivity enhancement of the stator windings at improved slot fill factor is investigated by performing steady state FEA thermal simulations and short time thermal transient tests.

This paper presents the manufacturing challenges of a transverse flux alternator for an aerospace application. For fault tolerance, four independent isolated phases are required to deliver a specific power at low speeds, whilst at over speed, there is a strict limit on the short circuit current. A transverse flux machine (TFM) was selected due to its high inductance combined with the modular nature of separate phases lending itself to fault tolerance. The stator consists of pressed soft magnetic composite (SMC) segments. The authors explore the electromagnetic, mechanical, and assembly design challenges of the machine. It is shown that mechanical design aspects of the segments are of equal importance to the electromagnetic design and optimization. Simple design choices have allowed the same component to be used as all the stator segments, despite the requirement of a 90° electrical phase difference between phases and a tooth offset of 180° electrical within each phase.

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This paper presents a comprehensive review of the modern thermo-conductive materials that have potential to improve the heat extraction in electrical machines by conduction. Currently, there is a significant interest in thermal design and analysis of electrical machines as the demand for high power/torque density is substantially raised in applications such as marine, aerospace, e-mobility and rail. Thermal design engineering has become very important to develop smaller and more efficient electric motors, therefore electrical machine designers need to be more informed with the recent development in novel thermoconductive (insulation) materials. Such developments can provide enhanced thermal characteristics for high power dense electrical machines. It is reported that high voltage electrical insulations can have more sophisticated thermal properties with the recent advancements in materials science. This study aims to inform electrical machine designers with and without a thermal background about recent thermo-conductive materials. Thus, a profound understanding can be gained in thermally conductive materials for the use of numerous applications in electrical machines for which thermal management is a crucial aspect of the overall multi-physics design and optimization process. INDEX TERMS Electrical machines, heat extraction, insulation materials, rotating machines, thermal analysis, thermal design, thermal conduction, and thermal materials This work is licensed under a Creative Commons Attribution-NonCommercial-NoDerivatives 4.