Abstract: Within the framework of analytical mechanics, dynamical modeling is investigated for an electromechanical system with a moving conductor in a magnetic field. The investigation yields the generalized forces resulting from the Ampere force acting on the moving conductor and the motional electromotive forces generated by cutting the magnetic field lines. The generalized forces and the motional electromotive forces are integrated into the Lagrange-Maxwell equations in order to derive the dynamic equations of the system. An internal resonance electromagnetic vibration energy harvester is treated as an example to demonstrate the application of analytical mechanics to the dynamical modeling of electromechanical systems.