In this paper, torsional vibration effects of a planetary gearbox on electrical signatures of a wound-rotor induction generator have been studied in a representative complex electromechanical system through both numerical simulations and experiments. A universal lumped-parameter model has been developed with consideration of impacts of main drive-train mechanical components. This model has been adapted to a reduced-scale wind turbine simulator based on a 5.5-kW three-phase wound-rotor induction generator used for experimental validation at different load conditions. For this system, it has been demonstrated that most of mechanical characteristic frequencies of the planetary gearbox are difficult to be identified in the stator current spectrum. Nevertheless, the proposed approach has been used as an initial stage to assess the effectiveness of noninvasive condition monitoring of a planetary gearbox based on electrical signatures analysis.