A system and method for controlling a rotating E-machine and for correcting a rotational position signal output by an angular position sensor operatively connected to the E-machine in conjunction with a sensor digital converter is disclosed. The return device has at least one first pump device and one second pump device, having respective inlet valves and outlet valves. To enable the machine housing to track the wind, the wind turbine is equipped with a pivoting device comprising a controller. The method according to the present invention comprises also a further step b) of inserting said tube structure inside a mold forming a mold cavity of a desired shape.