Inside a Wind Turbine Nacelle — 300 Tonnes of Secrets

That metal box on top of a wind turbine? It weighs as much as 50 elephants — and it turns to face the wind by itself.

We see these everywhere, but almost nobody knows what's inside. There's a whole power station up there.

The blades spin a shaft at about 15 RPM — far too slow to make electricity — so a gearbox multiplies it to around 1,500 before it reaches the generator, which turns that spin into three-phase AC that runs down a cable inside the tower to the grid. A hydraulic brake can lock the rotor in an emergency. And a yaw drive — an electric motor turning a ring gear — rotates the nacelle so the rotor always faces into the wind, automatically.

Here's the part that gets people: the computer reads the wind every second — and if a storm pushes past 25 metres per second, it feathers the blades edge-on and shuts itself down. The turbine is built to stop itself from making too much power. It protects itself.

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