The objective of this research is to develop and substantiate options that would enhance the efficacy of wind turbines with a capacity of five mega-watts or more by reducing the total weight of the generators, increasing the efficiency factor and reducing the converter power compared to those extensively used gearless wind turbines fitted with a low-speed generator. The latter is attained using dual-system wind turbines, where the system with aero-dynamic multiplication and the system with the low-speed generator are in typical operation. We have shown that the total weight of the generators in dual-system wind turbines depends on the power ratio between these systems. We have established that if this ratio consists of approximately 0.75 (when the multiplication factor is within the actual range), the mass of the generators’ active parts can be reduced by approximately 2 times with a higher efficiency than the wind turbines being used. In addition, the required power of the converter to connect the low-speed generator to the grid is reduced by approximately 4 times. The derived findings can be used for designing more than 5 MW wind turbines.