Lube oil failure?

[rl71459]

Be carefull Dan.

That documentation could render validity to my previous "Rambling" 

Rob

PS. The articles I have seen on the Drirect Drive units Still have some gearbox's/Lube for blade pitch and directional control and also a Hydraulic system with Motors (Not All have hydraulics)

[rcavictim]

A neodemium permanent magnet equipped armature, high pole count direct drive generating alternator for megawatt class wind turbines costs much more than a similar powered induction generator and gearbox system.  With the export restrictions now on rare earths from China these magnets have recently doubled in price.  A cheaper, more efficient solution to the gearbox is needed.

[dieselfox]

Gentlemen

I used to design big machines, which used big gearboxes.  I would have them made by Flender, now Siemens, up near Chicago.  When I would visit the plant I would go out and see the the big orbital gearboxes they were making for the GE windmills as they were a supplier for GE.  As I watched them through the years, they got better at what they were doing.  Finally, they put in a huge machine, which would run these big gearboxes under load for a specified period of time.  Then they would take all the lubricant out of the gear box, and have it analyzed, for any foreign material.  If they found anything, they would tear it down and find the source and then test them again.  
Oil as a lubricant works best at higher temperatures.  To say they do not have adequate lubricant for these gear boxes is just not correct.  
The biggest problem with these gearboxes, is that they are orbital in design.  They have planetary gears moving around in a big ring.  There is no place for any foreign material, a chipped gear, or any metal to fall out of the way.  It just falls to the bottom of the ring, and the next planetary gear that hits it is toast.  They do their best in heat treating to make sure the each gear tooth is not brittle but hard enough to resist wear, but nothing is always perfect.
From reading the posts, you have to realize, the gearbox oil is not the only thing that has to be cooled.  A generator is like a motor in revers.  It generates a lot of heat that has to be dissipated.
Your right about the Enercon now has a direct drive, but the inverters are huge.  Well the entire monstrosity is huge.
That is my two cents.
Dieselfox