The authors propose to work out common principles of synthesis of electromagnetic fleld models for the main types of electrical machines. The main objective is to create fleld models of electric machines by inheritance of their characters from the original Maxwell's equations. An inverse problem is being also solved | the synthesis of electric machine electromagnetic fleld equations using object-oriented design. Object-oriented design (OOD) implements the idea of solving problems using models based on the concepts of the real world. Fundamental element is an object that combines the data structure (parameters) to the behaviour (calculating procedures). Philosophy of knowledge representation in the form of objects of prisoners in their data and procedures developed by G. Booch, but so far only been applied in the fleld of software development, as well as an ideological foundation of programming languages such as Java, C++, C#, Visual Basic, Delphi (1). Consideration of OOD principles for the design and modelling of electrical machines (EM) at all stages, starting from analysis and flnishing with the project implementation, will enable a new approach to the EM design methodology and apply object-oriented theory, which revolutionized the information technology in the fleld of electrical engineering, which will signiflcantly improve the e-ciency and quality of EM design. We go out, assumes a basic class of generalized EM, descendants of which are well-known types of EM. By inheritance, using OOD principles, added or cut ofi those features which lead to the synthesis of a speciflc model of EM. Any EM can be described by Maxwell's equations. Select by equations features of a certain type of EM it is possible to form a hierarchical structure of species and thus obtain the desired EM model species level. The resulting model, inherited from the base class of Maxwell's equations, having the status of nature law, will adequately re∞ect the speciflc features of EM (2).