This paper presents and discusses the mathematical model of thermal phenomena occurring in axis-symmetric electromechanical linear motion converters. On the basis of the developed model, software to analyze the process of the heating up of this type of converters, was created. The effect of the thickness and type of material of the slot insulation, as well as the speed of the runner on the temperature distribution in the analyzed object was examined in-depth. Selected results of simulated calculations have been presented.