# Wind turbine torque

neonwarrior
Hello everyone,

I am reading a book about wind power turbines and found a calculation. I tried it myself and the numbers doesn't match.

Here is an image of the data and result.

I don't get to the same torque.

And also what do you think about the moment of inertia value?

Before the data the author gave the formula:

Homework Helper
Hi,

I don't get to the same torque.
I don't get the same torque either. Do we agree on some value ?
 It might just be a simple power of 10 the author 'forgot')

And also what do you think about the moment of inertia value?
Again, what do you get for a reasonable size windmill ?

 The author makes a mess of symbols and dimensions. Uses ##J## for moment of inertia (the 7500 kg/m2) AND for polar moment (m4) .
I find no way to balance dimensions in ##(5-4)##

##\ ##

Last edited:
neonwarrior
Hi BvU,

I wasn't aware that there was another moment of inertia (the polar). It's time to read myselft a physics textbook first LOL.

What I get is :

In the first one: converting first the rpm to rad/s

Net torque = J . (DELTA w)/ 5 seconds = 785.4 Nm

And the other question:
I calculated from some papers of windmills a moment of inertia of 113,000 kgm2

Yes, as you said, I think also there is a 10 factor missing or something.

Neonwarrior