When compared with the two-blade rotors, the three-blade rotors are more stable and quieter. The disadvantage of the two-blade rotors is that they need a special ‘wobble’ motor to prevent the severe collision when the rotor passes the tower. When the rotor blade is on top, the wind presses against it with full force and bends it. At the same time, the opposite rotor blade is in front of the tower. Thus, it cannot counteract the high pressure at the upper blade which leads to a strong jerk which is compensated by the wobble motor. This problem does not occur in three-blade rotors because the blades are never exactly opposite to one another. In addition, the three blades form a kind of disc for the flowing wind and are hardly prone to faults.
