In article the determination possibility of the transferring torsional moment of the face magnetic coupling with highly coercive permanent magnets is considered. The received mathematical expression allows at a stage of the engineering design to define the transferring torsional moment of the face magnetic coupling depending on the asynchronous electric motor maximum torque data given by the directory on electric motors, and to calculate a phase shift angle of semi-couplings taking into account their inertia moments, driven and slave rotating masses of machine, the operating torques of the electric motor, magnetic coupling and the machine itself on the stages of documentation development work.