The present paper presents the effect of inlet wind speed on the rotor power and efficiency of the horizontal axis wind turbine (HAWT). A proto type wind-cube is constructed, and it consists of two parts; the upper part is a steel sheet nozzle
and the down part is a base which used to carry the upper-frame and the generator chair. The cone shape nozzle is used
to increase the input air velocity. Four different rotors with different number of blades three, four, five and six have been
tested. The main aim of this study is to get the most efficient number of blades for the wind turbine used for this system.
Also, the study is aimed to investigate the minimum wind speed at which the wind turbine start to rotate and generate
energy for the system. The results showed that the rotor with six blades produced the maximum power compared to the
other rotors. Moreover, the results showed that, the minimum air velocity to start the rotation is 0.7 m/s and the power
was equal to 0.14, 0.17 and 0.39 W for the rotor with 4, 5 and 6 blades, respectively.