An algorithm for analyzing the operating modes of an agriculture electric machine as a control object based on its generalized mathematical model using the Fourier transform of non-sinusoidal signals of phase currents and conductance along the air gap of an electric machine is proposed, which is applicable to any electric machine with magnetic non-symmetry of rotor and which allows to obtain and investigate the spectral composition of such electric drive’s coordinates as induction and electromagnetic torque. According to such an algorithm, it is recommended to perform the calculation under the following assumptions: the machine is not saturated, the magnetic conductivity of steel is equal to infinity, there are no scattering fluxes. When going beyond these limitations, the calculation must be refined by a numerical finite element method using Maxwell’s equations. An example of an agriculture electric drive with a synchronous reluctance machine of independent excitation coordinates calculations is given according to the proposed algorithm in comparison with a numerical calculation by the finite element method.