Electromechanical systems are very common. The importance of constructing the dynamical equations of motors coupled with mechanical subsystems suggests a new strategy. In the literature, often, the derivation of the dynamical equations is wrong. One thinks that the standard derivations of the dynamical equations of purely mechanical systems can be mimicked to electromechanical systems. Unfortunately, it cannot. The main reason is that in electromechanical systems one deals with the presence of electromagnetic fields, continuous entities. These fields store electrical and mechanical energies. In purely mechanical systems the conservative mechanical energy is stored as elastic or gravitational energy, and the nonconservative terms enter the equation as nonconservative forces. This cannot be done in electromechanical systems. This project shows the right way to derive the dynamical equations applying the results for systems formed by a motor, a coupling mechanism, and a mechanical subsystem.