4 ms·
rapelled? (still sounds terrifying - presumably they were stationary?)
by andrewcooke 14y ago
rapelled? (still sounds terrifying - presumably they were stationary?)
- sopooneo 14y agoI assume OP means repelled down the tower, not the blades.
- defrost 14y agoRapelled, as in abseiled down on a rope, rather than repelled, as in forced away from.
- startupfounder 14y agoNope, I do in fact mean the blades. Because blades are made up of 13 tons of fiberglass they bend and vibrate a lot. You have to visually inspect the blades to make sure there are no cracks or de-lamination. If there are you have to do the repairs while on rope in winds blowing up to 12 m/s. It is in fact an extremely safe industry, Industrial Rope Access. With over 25m man hours on rope around the world there has only been 1 death offshore in the north sea in 2011.
- startupfounder 14y agoYes, stationary. When you lock out a wind turbine you stop the rotation by pitching the blades back to 0 or break them so that they do not generate any power, second you apply a giant hydraulic break. But this is not enough. The last thing you do is put a missive steal pin ~6" diameter by 12" long through a very large disk with many ~6" holes that is attached to the main shaft going from the hub (where the three blades are attached) to the gearbox (that has a 70:1 gear ratio). Only then are you able to tie anchors to the generator, bring the ropes up on top of the nacelle and rappel off the 250' to the ground.