This article performs a thorough evaluation of different environmental and electrical waveform characteristics affecting PDIV on electric motor winding insulation. Temperature received special attention, as it clearly affects PDIV. Additionally, the PDIV models found in the literature were reviewed. Considering that the winding of the electric motor can reach 180 ${}^{°}$C during operation, the experiments were performed at high temperatures in order to evaluate the performance of PDIV models. Several models were studied regarding their accuracy at high temperatures and the advantages and disadvantages of each one were identified. Based on the analysis, a simple analytical model to estimate the PDIV of twisted pairs depending on the temperature was proposed. All in all, the proposed model was the best compromise between computational requirements and PDIV estimation accuracy at high temperatures. Finally, future lines were identified. Further studies are necessary that consider the humidity, rise time, and pulse width effect on PDIV. Moreover, new models regarding both, environmental and waveform characteristics are necessary to accurately estimate PDIV. Extended volume–time theory seems to be a good basis for that.

The extrusion speed and deformation temperature are important factors affecting the microstructure development during the deformation. Microstructure development plays a crucial role in the performance of the mechanical properties of materials. In direct extrusion, the homogeneous evolution of the microstructure in the length of the extruded bar could be affected due to its non-isothermal exit temperature evolution. Thus, a new set-up is suggested with real-time controllable speed and temperature to characterize the influence of temperature on the microstructure and obtain its homogeneous development for the magnesium alloy. During the extrusion, the temperature of the extruded bar is evaluated by using the infra-red camera, and the extrusion speed is simultaneously controlled in real-time depending on the temperature difference between a set temperature reference and the one obtained from the infra-red camera. This suggested set-up of extrusion is evaluated in terms of the microstructure and temperature evolution of the extruded bar.