Patent ID: 8371976

Claim:
A wind turbine generator comprising: a blade having a blade ring; a nacelle turning unit having a circular part; an internal gear which is provided on an inner circumference of a circular member that is one of the blade ring of the blade and the circular part of the nacelle turning unit; a plurality of pinion gears which meshes with the internal gear and is connected to a plurality of drive motors, respectively and which includes at least a first pinion gear and a second pinion gear; a controller; a timer from which a timing signal is inputted to the controller; and an encoder for detecting a signal of rotational displacement per unit time of the drive motor based on the timing signal inputted from the timer; wherein the controller controls a rotation of the plurality of pinion gears independently via the plurality of drive motors based on the signal of the rotational displacement inputted from the encoder, and wherein the controller is configured to perform a control so that, during a transition period when the circular member is to be stopped, there is a difference in a speed reduction rate or a circumferential speed at least between the first pinion gear and the second pinion gear.