Degradation of PAI/PEI Enamel under High Temperature (Up to 400°C)

Abstract

This work deals with the understanding of the degradation of the primary insulation (PEI/PAI) of rotating machines working temporarily under high-temperature. The main domain of application of these motors is the smoke extraction either from tunnels or underground parking when a fire occurs. In such a critical situation, the internal temperature of the motor winding may reach temperatures up to 400°C. Under such very high thermal stresses, the behaviour of the electrical insulation is not well understood. This work proposes an analysis of the decomposition gases under very high temperatures and the corresponding degradation pathway. A simple method is proposed to identify whether the insulation of such motors has been strongly damaged during the working time at very high temperatures, thus allowing estimating if it can still continue to operate.