The present paper reports non-electrically intrusive partial discharge investigations on aeronautic and electric vehicle motors fed by SiC inverter drive under variable environmental conditions. A representative test procedure and experimental set-up based on operating aeronautic conditions are essential to ensure the accuracy and reliability of partial discharge test on aircraft systems to make informed decisions on insulation system design choice. The aim of this paper is to demonstrate the feasibility of partial discharge test of the insulation system on a different type of motor under such conditions, both electrically and environmentally. To do so, the paper will start by detailing the innovative experimental set-up to be used in the study. It mainly consists in a high-voltage (1000V) inverter drive using SiC components to provide fast rise time surges. A vacuum chamber is used to simulate altitude while the association of non-intrusive sensors, analog filtering and wavelet based signal processing provided partial discharge detection. Then, an analysis is carried out on several motors to find out which voltage magnitude trigger partial discharge events. The study helps to realize the benefits of using an inverter based test method to find the limits of the insulation system under various pressure and electrical conditions. It is shown that a representative insulation system performance picture could be drawn experimentally and used to enhance insulation design and manufacturing choices. This paper will also review the ability of the non-intrusive test method and the associated numerical signal processing to detect partial discharge in a motor fed by fast-rise time surge and under different pressures. The paper concludes with an analysis of results and thoughts about future work regarding advanced test procedure.