The wind turbines were turned off...

Discussion in 'UK DIY' started by Man at B&Q, May 4, 2011.

  1. Man at B&Q

    Man at B&Q Guest avoid fanning the flames

    Heard during a report on R4 this morning about countryside fires.


    Are people really that stupid?

    Man at B&Q, May 4, 2011
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  2. Do you really need to ask?

    Or do you just not meet the great unwashed on a regular basis?
    John Williamson, May 4, 2011
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  3. IN what way? for sure turbines increase ground level wind.

    You get a lot of wind shear, and the turbines 'stir' the layers..

    But I'd expect it to be a safety if firefighters were around, or there
    was a chance the turbines could catch fire (I wish)

    But is it a true story?

    I dont listen to radio 4 PC lefties any more..
    The Natural Philosopher, May 4, 2011
  4. Do you have to ask?

    There might be an element in truth in that to stop damage to bearings
    when sat still for long times they are motored round. There is f'all
    wind ATM, 300MW from wind when I looked a few minuets ago. About 1%
    of the total installed wind capacity...
    Dave Liquorice, May 4, 2011
  5. ITYM 10%...

    In fact that's a fairly normal figure and reflects a medium breeze.

    Wind farms seem to spend most of the time between 5 and 15% output, with
    occasional excursions above 50% to 'make the figures look good' and
    occasional excursions below 5% which don't overall make a lot of
    difference to the averages, anyway.

    To put it in simple terms, the 25% average is actually more or less
    10-15% most of the time, with a few days of >50% and a few more days of
    less than 5% interspersed.
    The Natural Philosopher, May 4, 2011
  6. Man at B&Q

    Allan Guest

    I didn't hear the report on R4, but if it's Ovenden Moor near Halifax,
    there are currently moorland fires up there, and there's also a wind
    farm on the moor too.

    Allan, May 4, 2011
  7. yep. fires are very common. Generally if the mains frequency stops them
    over speeding, if the wind is too strong they should feather to keep the
    torque down. If the feather fails either the generator will overcurrent
    or the gearbox will overheat and catch fire, or the bearings will fail
    and the same thing happens. If they lose connection to the mains as the
    windings burn out, then the thing will overspeed and shake itself to pieces.

    It is rumoured as little as a .22 round in the right place can cause this.
    The Natural Philosopher, May 4, 2011
  8. Man at B&Q

    newshound Guest

    newshound, May 4, 2011
  9. Have you got documentary proof of that?

    The Other Mike, May 5, 2011
  10. I've seen the video yes.

    So yes and overspeeding turbine will disintegrate.

    That takes in general a cascade of failures..the feathering mechanism
    has to fail, and then either the gearbox or anything else that keeps it
    as a certain speed. Earlier fixed speed turbines are synched to the
    mains I think. Modern ones use inverters. But anything that takes the
    load off the turbine without it feathering will cause it to disintegrate
    in a strong wind.

    There is for that reason a safety exclusion region that is broadly as
    wide as the turbine is high.

    There is some evidence that lightning strikes can remove a blade as
    well..that leads to disintegration as well if it also takes out the
    feathering system.

    Too high seas in a marine locale will result shutdown as well, as will
    sufficient blade icing. Note that ice that does not seriously unbalance
    the turbine will simply be thrown off. Up to 200 meters estimated, at
    speeds of up to 150mph. .

    But the most common cause of drastic failure is overheating gearboxes,
    and especially bearings. Fluctuating strong magnetic fields together
    with water - especially salt water - are the perfect way to induce
    electrochemical corrosion in metal bearings. Secveral times a year...;-)
    The Natural Philosopher, May 6, 2011
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