In this thesis You can find my description about the check calculation of a permanent magnet syncronous generator done by the japanese 3D finite element method software JMAG. I introduce the preprocess, the solving and the postprocess of the results. The target of my calculations is to determine the parameters being in the equivalent circuit of the electrical machine such as open-circuit voltage, armature reactance, terminal voltage and armature current belonging to nominal load. Besides I determine the load-angle-depending characteristic of torque and the nominal load-angle. Eary in the description I say some words about the finite element method (FEM), and the free 2D FEM software FEMM. I summarize the basic cognition about syncronous generators and report the results of my former check calculation of the proposed rotary machine. As continuation I introduce the steps of creating the geometry in JMAG Geometry Editor, then I describe the settings made in the software, so that it means help in case of solving a similar problem. This documentation contains the process of defining materilas and connecting them to the parts of the machine, just as the creation of circuits and connecting their elements to the parts of the machine. The proper setting of the solver also can be found in the documentation, and it does not lack the settings needed to simulate the magnetic field. To solve a 2D problem, I apply 2D model, but then I present a 3D problem as well: the loss in the magnet caused by eddy currents and their effect on other parameters. After applying the two models I display the results in graphs, compare them and heighten their deficiency. After the evaluation of my calculations I mention some directions in connection with developing the model with which we can achieve more precise simulation and get closer idea about the parameters of the machine. In the digital appendix among others You can find tables and graphs epitomizing my results and an animation demonstrating the magnetic field of the machine in operation.