# Information regarding wind turbines

## Main Question or Discussion Point

Im looking for information regarding wind turbines. A 1.5 megawatt turbine rotates at 20 rpm and requires 338 kilonewton meters of force. A 100 kilowatt turbine rotates at 60 rpm and requires 19.4 kilonewton meters of force. Both are gearbox driven generators.

Is there a formula that is used to determine these torques? I do not have the intellect to successfully determine this. Is more information needed in order to get the result?

Kit

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Im looking for information regarding wind turbines. A 1.5 megawatt turbine rotates at 20 rpm and requires 338 kilonewton meters of force. A 100 kilowatt turbine rotates at 60 rpm and requires 19.4 kilonewton meters of force. Both are gearbox driven generators.

Is there a formula that is used to determine these torques? I do not have the intellect to successfully determine this. Is more information needed in order to get the result?

Kit
$$P=T\omega$$

Check out: http://en.wikipedia.org/wiki/Torque

power in watts=the torque in newton meters X the angular velocity in radians per second

1 degree = (2 X pi)/360 radians

20rpm = 7200 degrees per minute = 120 degrees per second = 2.094 radians per second

torque = power divided by angular velocity

1.5 megawatts = 1,500,000 watts

required torque = 1,500,000/2.094 = 716,332 newton meters = 716 kilo newton meters

this value is just under twice that of that stated in your question so im not sure what the value you've stated is for (possibly the torque and rpm values are from different ends of a 2:1 gearbox?). however i did the same working for the other turbine values and got 15.9 kilonewton meters which is slightly lower than the stated value which makes sense because you need to acount for the efficiency of the generator and power losses through the gearbox etc.

iv just noticed that the value i calculated for the first turbine is in fact more than double the value stated. i dont understand at all the origins of the number you found. mabye a 3:1 gearbox with pretty bad efficiency? or the wrong number? i know nothing about wind turbines, just a bit about torque so thats all the use i can be i think.

just out of interest whats this for? if you dont mind me asking.

stewartcs
Im looking for information regarding wind turbines. A 1.5 megawatt turbine rotates at 20 rpm and requires 338 kilonewton meters of force. A 100 kilowatt turbine rotates at 60 rpm and requires 19.4 kilonewton meters of force. Both are gearbox driven generators.

Is there a formula that is used to determine these torques? I do not have the intellect to successfully determine this. Is more information needed in order to get the result?

Kit
http://www.rpc.com.au/products/windturbines/wind-book/wind4.pdf

This should explain it in detail if you feel like reading.

CS