Breastshot waterwheel is the main component at microhydro power plant. At the breastshot waterwheel, there is a blade used to receive the action force of the water flow capacity to generate a reaction force in the form of a wheel rotation. Number of blades affects the rotation of a wheel. To get the maximum effect of the collision of water, it is necessary to change the number of blades in order to obtain the maximum wheel rotation. The numbers of blades in this research are 15, 18, 24 and 30 pieces. At the testing time, number of blades changing was conducted alternately to determine the number of blade generating the optimum output power. The connected waterwheel with the generator rotated when the collision had the potential energy. The wheel rotation and generator were measured using a tachometer. The amount of electric current and the output voltage of the generator were measured using a digital multimeter. The outputs of the breastshot waterwheel were the wheel rotation and the generator rotation. The output of the wheel was used to calculate torque and efficiency. The blade form was a square. Based on the testing, the highest number of blades was 18 pieces; with 64,3 rpm wheel rotation; 31,46 Watt generator output power; 28,17 Nm torque and 10,9 persen efficiency.
Keywords: The number of blades, Rotation, Power, Torque and Efficiency