This paper provides an analytical solution to one of the main objectives within theoretical foundations of electrical engineering, formulated in particular to reflect the decision making while designing new types of synchronous generators with permanent magnets. The necessary for such generators is determined, above all, by development of the area of small-scale energy sector due to the emergence on the consumer market of affordable and accessible strong magnets of neodymium alloy NdFeB. The purpose of this paper is to obtain an analytical solution for the determination of the induced Electromotive Force (EMF) in the loop placed in a magnetic field of the permanent magnet of rectangular cross-sectional shape while in relative motion. A generalization of the results of research on an arbitrary cross-sectional shape of the permanent magnet is presented. An example of in the calculation of the magnetic system of a magneto-disk machines based on the finite element analysis by software ANSYS is provided.