Nowadays there is a tendency towards the replacement of small direct current motors with electromagnetic excitation by permanent magnet direct current (PMDC) motors. Application of field methods for simulation of PMDC motor complicates its mathematical model and requires considerable amount of time for the processing of the results obtained. The purpose of the paper is development of a mathematical model of PMDC motor on the basis of theory of electric and magnetic circuits. The mathematical model of PMDC motor has been developed on the basis of the ramified equivalent circuit of the motor magnetic core featured by high level of magnetic core detailing. In the paper, the procedure for the equivalent circuit development and the method used for determination of its elements are described. The equations of magnetic, electric, and mechanical equilibrium of PMDC motor have been obtained. The mathematical model enables us to calculate transients and steady state characteristics of a PMDC motor with sufficient accuracy.

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