Wind is clean, renewable, and homegrown energy source of electric power generation, and has been positively/effectively utilized to cope with the warming global environment. The conventional turbines with large-sized wind rotor generate high output at moderate wind. The power generation of the small-sized wind rotor is low but is suitable for weak wind. That is, the size of the wind rotor must be correctly/appropriately selected in conformity with the wind circumstances. Moreover, the turbines must be equipped with the brake and/or the pitch control mechanisms, in general, to suppress the abnormal rotation and the generated overload at the stronger wind, and to keep good quality of the electric power. To overcome above weak points, the authors have invented the superior wind turbine generator, as shown in Fig. 1. This unit was called “Intelligent Wind Turbine Generator” by the authors, as the rotational speeds of the tandem wind rotors are adjusted pretty well in cooperation with the two armatures of the generator in response to the wind speed. This unit is composed of the large–sized wind rotor, the small-sized wind rotor and the peculiar generator with the inner and the outer armatures without the conventional stator. The front and the rear wind rotors drive the inner and the outer armatures respectively as shown in Fig.1. The rotational torque is counter balanced between the inner and the outer armatures of the generator. The rotational direction and the speed of both wind rotors/armatures are free, and automatically determined in response to the wind circumstance. The superior power generation of the proposed wind turbine generator was verified in the previous report. Continuously, this paper shows the effects of the front wind rotor profiles, the axial distance and the diameter ratio between both wind rotors on the turbine characteristics, in accompanying with the flow conditions around the tandem wind rotors-were experimentally investigated and shows the characteristics of the superior generator.