How does wind spin those giant turbines? It seems like even high-speed winds wouldn’t move it very quickly with how heavy the turbine blades must be.
In: Planetary Science
the turbines are calibrated to rotate at a minimum and maximum speed…once they exceed their RPM the blades will pitch to prevent the wind from rotating them to reduce damage to the unit and or course safety reasons.
when the wind gets to strong, they have to lock them down. it’s not pretty when they spin too fast and fail catastrophically. well…it kinda is- but not if you own or insure it. or if you happen to be in too close a proximity to it.
The blades are on a bearing – something that allows rotation with very little friction. At that point, the weight isn’t very important. The blades spin *very easily*.
Combine that with their enormous length, which gives the wind very powerful leverage on the shaft, and they spin with ease.
If you spin the turbine its like a fan, it ‘blows’ air. So if you ‘blow’ air against it, it will spin. And when one blade goes down (because its heavy), it pulls the other blades up.
Already answered, but as a side note, wind carries an incredible amount of energy. You can feel the force on your hand (which has a very small surface area) when you stick it out the window of a car at highway speeds. I sail catamarans and you can easily break the rigging if you don’t reduce sail quickly when the wind picks up. The blades of those large turbines are around 40m so the surface area is huge.
It’s kind of like the wing of an airliner. There’s a lot of force (lift) keeping it airborne. But if you watch it cruising along, it doesn’t look like the plane is going fast enough to keep it aloft. There’s a lot more force than you would intuitively think
being massive doesn’t prevent an object from moving. Only other forces on an object can do that.
We live in a world where friction is everyhwere. And massive objects often dig into the ground a lot to prevent us from sliding them.
And gravity pulls down on them hard, preventing us from lifting them.
But if you get rid of the other forces (really low friction) you can make anything change it’s motion. Massive things just have a lower acceleration when you push.
So the huge blades are just slow to begin turning, as the bearings remove almost all the friction. And they’re slow to stop turning.
I work around wind turbines. The blades are balanced around a central point. With a rope tied to 1 blade, a couple adults can start it spinning.
1. It is designed to spin with as little friction as possible.
2. Air has more mass than we give credit for. We hear a lot about the scary pressures of the weight of the ocean, but the atmosphere is no different, we are just don’t feel it because our bodies are adapted for it.
Examples of it’s force:
If a train metal container is cleaned with vapor and sealed before it’s cooled off, it will be crushed by the weight of the atmosphere just like a aluminum can.
Have you see the explanations of how a airplane can fly, and they tell you about pressure difference of the wing and you just nod and pretend you understood. In a nutshell there is a “vacuum” of pressure above the airplane, and the weight of the air bellow is being pushed up by the rest of the atmosphere to fix that pressure difference.
The wind that pushes the turbines is actually tons and tons of air being heated and expanded by the sun, and even at low speeds it builds momentum, at high speeds I’ve seen videos of turbines being torn off.
TLDR: If the atmosphere can lift a airplane, it can move turbines.
Air weighs about 14 lbs per square inch. It’s actually pretty heavy and can move large objects with seemingly a light breeze. Wind moves giant boulders across the desert sand. It’s crazy strong.
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