This paper describes the techniques for testing the winding resistance of a synchronous generator with auxiliary Diesel power supply. After a short theoretical introduction describing the principle of a synchronous machine, an overview of the measurement methods is given (indirect measurement using the U-I method and direct four-wire measurement). The central part of the paper is practical measurements of 2 synchronous generators, analysis of the results and conclusion on the correctness of the machine in the context of the amount of winding resistance.