I do not know if there is such a thing as the heart of a wind turbine. Ultimately, all parts are important. But the main axis is certainly close to being something like a heart.
Several components are combined in it. Similar to the hub, it has to absorb all forces but at the same time pass on the rotation of the axis to the generator with as little loss as possible. In addition, it must be freely rotatable so that it can be aligned in all directions. Last but not least, it should also include the mechanical braking system with which the wind turbine can be stopped completely.
In the "Nerdiskerator" two ball bearings are installed, which could possibly even take the weight and the forces of the wings. But, I did not want to put additional wight/forces on these ball bearings. After all, they already carry an important payload. :)
That's why I built a shaft in front of the "Nerdiskerator" which is supported with two angular roller bearings. These can accommodate not only the radial (perpendicular to the axis) but also the axial (in the direction of the axis) forces. I had hoped on the one hand to support the shaft in a stable manner and on the other hand to support it smoothly and quietly.
This shaft is connected via a rubber damped coupling, which enables the rotation to be transmitted. (More on that later)
The whole thing is held together using the same aluminum profiles that I had already used when building the wings. These will later also serve as outriggers to mount the wind vane.
As always, here are a few photos of the described structure: