Design and Testing of a Steam-Resistant Insulation System for the Stator of a Low-Voltage Turbo-Generator Taking Thermal Aspects into Account

Traditional insulating materials used in low-voltage machines cannot normally withstand steam because of the simultaneus presence of high temperature and humidity. In order to find a steam-resistant insulation system that includes magnet wire, groundwall and phase insulations and impregnating resin, accelerated aging tests were carried out applying small-scale models. Eight different insulation systems were constructed on these models, and seven different wire insulations were tested. The specimens were immersed in hot, pressurized water, which influenced the material instead of steam. Suitable materials for each part of the insulation system of a low-voltage, random-wound machine were found. Taking into account the thermal conductivities of each insulating material, the heat transfer of the machine was calculated for all the tested insulation systems.