[en] To simplify a structure and to reduce metal expenditure for the production of electromagnet windings of an ring cyclotron it is suggested to make upper and lower electric windings in the form of rings. These windings are common for all sector magnetic core units, the units placing in azimuth so that electric windings are placed into the magnetic core. Such electromagnet structure is simple for the production and in addition a necessary magnetic field is reached with a lower electric energy expenditure which is due to the absence of end connection sections causing additional stray fields