With the ever increasing pressures in automotive industries to develop smaller and more efficient electrical motors for their applications, it becomes necessary to have a thermal model at the design stage. This study proposes a fast, precise and practical thermal model construction that requires minimal development time for a synchronous reluctance machine which is to be used in automotive applications. It uses a method we call “practical experimental fitting method” which corrects a basic and simple thermal model by adding corrector coefficients into the model in order to fit it to experimental results obtained from the first machine prototype.