Eli5: windmills
Why is it that in an entire group of windmills all facing the same direction and all right next to each other, you sometimes only see one or two moving and the other windmills aren’t moving at all?
I’m driving through California and noticed this, which is prompting my question. I would expect all of them should be turning, so I think they’re either immobilizing most of them, or manually spinning those windmills somehow. In either case, why? Or am I wrong in my assumptions?
In: 43
To add still more – turbines can be ‘turned off’ by:
* a brake of some sort on the shaft
* increasing the resistance between the electrical/coil and the magnets until the turbine locks up
* de-coupling the blades from their “pointers” so the blades just blow with the breeze instead of sticking out into it
The last one requires the least amount of wear and tear, and on its own or in conjunction with a brake is usually enough. You *don’t* want to leave the blades locked-out and just use the brake though, because then the turbine will try to keep turning and you put a lot of extra stress on the brake mechanism. And I do mean just the blades here, they are on a separate “pointer” from the housing which can also turn. The blades can be angled forward/backward to increase or decrease the rotations per wind speed, by decoupling this the blades just ‘feather’ like a windsock rather than provide resistance (which is what makes the turbines turn). When the housing turns, that is to point the face of the turbine in the desired direction, which can change depending on the primary wind direction.
I’m not sure how common it is to use resistance as a method and can’t comment on that.
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