Wind turbines are windmills that are useful for generating electric power. In the need for energy to meet the development of the times resulted in increased fossil fuels, therefore other alternative energy is needed to overcome the decreasing fossil fuels. One form of energy that exists in nature la wind. Therefore, wind turbines are starting to be used as alternative energy power plants. The purpose of this design is to find out and test the use of blade lengths of 43 cm, 53 cm, and 63 cm with 3 blades which produce the largest turbine output voltage with a horizontal type turbine which will be used in the rooftop area of the Global University Jakarta. The design method is to test the horizontal type wind turbine which has 3 blades made of iron plate (log fuam) with a thickness of 1.2 mm. The results of the blade design show that the theoretical data at the highest wind speed of 3.3 m/s can produce a turbine output voltage of 11.56 volts and a shaft rotational speed of 416.8 Rpm. In these conditions indicate that wind speed and blade size greatly affect the turbine output voltage and shaft rotation speed of the design results.

Key words: Power Plant, Wind Turbine, Blade, Wind Speed, Turbine Output Voltage, Shaft Rotational Speed