The paper considers the study of the electromagnetic field of a synchronous generator based on the three-phase induction machine. The stand includes: a frequency converter, an induction motor, a synchronous generator, a three-phase rectifier, an active load resistance, power protection and inclusion industrial electrical network. The study provides an analytical solution to one of the main objectives within theoretical foundations of electrical engineering, formulated so to reflect the decision making while designing new types of synchronous generators with permanent magnets. The necessity 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. The pictures magnetic field of the generator in an idling mode, the transverse and the longitudinal armature reaction at the nominal current in the stator winding are presented in the paper.