Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

Information regarding wind turbines

  1. Jun 3, 2008 #1
    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?

  2. jcsd
  3. Jun 3, 2008 #2

    Check out: http://en.wikipedia.org/wiki/Torque
  4. Jun 11, 2008 #3
    power in watts=the torque in newton meters X the angular velocity in radians per second

    1 degree = (2 X pi)/360 radians

    so for your wind turbines:

    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.
  5. Jun 11, 2008 #4


    User Avatar
    Science Advisor


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

Share this great discussion with others via Reddit, Google+, Twitter, or Facebook