Observe the picture below, taken from this link.
Now compare the figure above with the same shaft (being rotated by the turbine) with a torsional moment, but now the other end is fixed to the wall (instead of being attached to the generator with bearings in between). For this case, I can understand that a net reaction torque must exist on the shaft face which is attached to the wall, because the wall is exerting equal but opposite torque on that face, to ensure an overall equilibrium system. But for the figure attached here, the shaft can rotate without any restriction or resistance from the generator, because they have ball bearings in between.
So can someone just tell me that is the system shown in the figure in equilibrium or not? Because the figure shows presence of reaction torque but the rod still rotates without any resistance. Plus, why does the reaciton torque even exist in this system?