Some words about safety - The mechanical brake system

A project log for WinDIY - HAWT Wind turbine

Mostly 3D printed HAWT windturbine incl. 3D printed disk-generator and brake system.

FabFab 06/13/2020 at 11:180 Comments

I think it's always healthy to have enough respect for big rotating things. "Big" starts with relatively small things. For example, nobody would voluntarily want to slow down the kitchen mixer with his bare hand. It is not for nothing that there is an off switch on the kitchen mixer. :)

But what do you do with a wind turbine that turns quickly but should now be stopped for some reason. Turning off the wind (unfortunately and fortunately) does not work.

That's why I tried to think a little about how WinDIY can be reliably controlled or braked even in strong winds. The power (and speed) can be controlled within a certain range using the controlled load on the generator and the pitch adjustment of the blades.

Unfortunately, the wind turbine cannot be brought to a complete standstill. For this reason, I have planned a mechanical brake system.

As you can see on the video I used two brake blocks of an old bicycle brake for this purpose. These can (in the current design) be controlled by a servo and pressed onto the short-circuit ring of the disk generator.

This short-circuit ring is actually intended to "short-circuit" the magnetic field lines of the magnets in the disk generator. But it is also very suitable as a relatively abrasion-resistant surface for the mechanical brake. :)

As you can also see in the video, the contact pressure of the (human simulated) servo is by no means sufficient. Here we need more power.

I am currently working on realizing the braking system via a stepper motor. This should drive a spindle, which in turn generates the brake pressure. I also plan to install a sensor that can measure the contact pressure. This way the system could measure which contact pressure is currently present and whether this is already sufficient to reduce the speed. This then spares the stress on the mechanics and the brake pads. :)

So therfore here comes a video and a few photos that basically show how you can NOT design a brake system. :D