Bearing woes

[kitestrings]

Dang.  I’m pretty frustrated right now.  I just was watching the turbine running today in light to moderate winds.  When the wind shifted direction and it yawed around, I winced to hear that clunking/clapping sound I thought we’d just corrected.  It’s a nice, mild day so I scampered up to have a look/see.  Sure enough we’ve got significant bearing play; again.  I’d recently re-tightened & lubed the outer bearing, but did not replace it.  I took from BigRock’s cue to torque the thing a bit tighter, and gave it a few good seating hits with a mallet & block at the hub, then backed off only a flat (or maybe two), so it was fully seated.   

It ran well – quiet, balanced – but not for very long.  I assume the inner cage must be failing?
 
It's a pretty major repair to pull the blades, stator & magnet rotors to get at the back bearing… though I guess everything could stay up on the tower this time.  Maybe I should be thankful that I can do this with the removeable coil sectors.  With most axial’s this would not be an option.  Just wish I’d gotten to it this summer.  We just got about 10” of heavy, wet snow and the days a short now & windier.


Got’ta find a better, long-term solution.

[kitestrings]

I was just looking... and this set of bearings was new in November 2020.  Maybe that's good wear, but it doesn't seem very long at all.

It's a 4,910# Baum hub with Timken (#25877, #25590) tapered roller bearings.  Maybe I'm not putting enough grease thru it?  Maybe it's the wrong bearing for the application - Chris has said this out-right.

[MattM]

You are going on 4 years.  That was your moneys worth.

[bigrockcandymountain]

That really sucks.  I hope you can get it fixed quick.  Winter is no fun with no wind power. 

Just my opinion, but I think you should get better service out of them than that.  You could go with a larger series hub if it would fit inside your generator.  You could try a different bearing brand.  Timken is one I have always trusted, but I don't buy more than a handful of bearings a year, so it's hard to say. 

Skf would be my other go to. 

You can put a bearing cap/cover on with a grease zerk in it.  Then pump until it pushes out the back seal.  That way both bearings get grease.  I think you could do that with the blades on.  Maybe that's what you have.  I don't remember how you grease. 

Synthetic emb grease would be my choice for grease.  Do as i say, not as i do haha.  I use EMB, (electric motor bearing) grease, but not synthetic.  And it shows when the temp goes below -20c. It doesn't spin up near as easy when it gets cold. 

I'll wait the results of you taking it down.  I don't envy you that project, especially when it is cold. 

Safe climbing.

[Mary B]

There are a LOT of counterfeit bearings on the market, make sure you buy from a reputable source(your local auto parts store IS NOT on the list! Corporate bean counters buy cheap crap!).

Think about it, that bearing has been up there 4 years, approx 35,000 hours, Timken rates them for 3000 hours at 500 rev/min... I think you passed that!

[kitestrings]

Thanks all.  A few thoughts, not necessarily in order:

It's closer to 3-years, but we also shut it down quite a bit.  Summers for example, the winds are lower and we usually have ample PV.  I also regularly shut it down at night.  I have great neighbors, but I don't want it (noise) to be an issue if I can avoid it.  I think the run-hours are considerably less.

They are Timken bearings.  I bought them with the hub from Baum Hydraulics.  They are a long-time US manuf.  I also bought two additional sets of replacements, so I still have one.

The hub has a grease zerk that dumps in the middle.  I had replaced the stock zerk with a 45 degree fitting and drilled the downwind plate to allow access.


Grease.  Below is what I'm using (Molly B?).  Perhaps this is an area for improvement.


Thoughts on how it failed?  The play is probably .125" to .1875" at the rotor radius if I had to estimate, so I assume the cage is failing(?)

The weather looks good on Saturday.  I may just have at it.

[clockmanFRA]

+1 As 'Mary B' said, fakes everywhere.

I have had fake timken, fake SKF, fake everything, yes things are really that bad.

What i do now is everytime i get a new bearing i give every bit a good QC, no matter who supplies it.

Except for stainless coaxial bearings, all steel taper etc bearings are hardened and temperd.

I use a very fine Swiss Valrobe needle files and actually try to file the outer, inner and the cage and the rollers/balls, yes it screws up a file as the file should not cut and should slide over. But after my testing at least i am happy with each bearing.

We shouldnt have to, but today unless you are standing over the bearing manufacture as they machine and heat treat there is no way of gathering that its genuine. As the box printing is exact copies of the genuine complete with 3D imaging and everything.

Oh Yea, for those folk here saying get a well known make, ....... A couple of years ago i  purchased brand new Timken from a Timken authorised seller and i tested them, and they failed my testing.  I Personally went to the well know firm in Europe and was fobed off,  I showed my test report and photos and had a heated discussion with Timken selling morons.

In the end they gave my money back but never admitted that they were fualty and not hardened correctly.

So get some new fine needle files and test each new bearing yourself.

If you are wondering, .... I have done heat treatment on high carbon steels for most of my working life, and its a skill not easy to master.

[kitestrings]

Wow.  Thanks for sharing this - I had no idea it was this prevalent, or how one could tell.

I had one other idea here:

The first, and last, time the alternator came to the ground (~2019/2020), it was for some pretty extensive work.  Not to divert too far, but we had some corrosion issues, stress cracks in the stator rings, blade work, etc.  We removed: 1) the blades, 2) the stator, and 3) the hub & magnet rotors assy.  We were able to then leave the head assembly, the tail, tail boom, hinge, vane, spindle, and stator bracket... so the heaviest lift was only about 135#.

In this case, nothing really needs to come down, and I really only need minimal separation of the hub off the spindle; enough to change the downwind bearing.  Why couldn't I leave the stator wired and between the magnets, as an assembly, and held by just the stator rings?  If I removed the six button-head bolts connecting to the stator bracket, the stator would be loose but held together by the rings (each sector has a separate through-bolt).


On the plus-side it would eliminate disconnecting and dismantling the stator.  On the down-side it would add about 28# to the lift - so now we're looking at 160-165#.  What am I missing... likely something?

[SparWeb]

I know this doesn't help much, but I agree counterfeit bearings are a big problem that doesn't seem to be going away.  So I'm just piling on my opinion to what's already been said.

You just re-lubed it, didn't you? So I don't think that's the problem.

Handling heavy loads on the hoist...  Can you anchor a sheave to the ground?  Clearly if you weigh 160 pounds and the mass on the hoist (at 1:1) is 165 pounds, well then you're about to have a bad day.  But if you anchor a sheave on the ground, then you can use your legs, like lifting weights.

Better to not need to do this, so hopefully there's a workaround that doesn't require lowering the head nor making it more massive.

[Mary B]

A gin pole is required for a job like this...

For those who don't know what a gin pole is or how it works this is a good video demonstration. At the beginning he talks about an out of control load crashing over after a rusted bolt snapped, a load that was probably 100+ pounds! Gin pole held it instead of having the load crash to the ground. His demo is light tower sections but a proper gin pole can handle the weight you design it for, commercial tower stackers lift 1,000 pound tower sections! He is a bit long winded...

https://www.youtube.com/watch?v=cZwf5IqkBWs

[kitestrings]

Yes, that's right.  Neil, my long-time climbing buddy and I erected lots of towers, and set, and took down many turbines back in the day.  We almost never had a crane, but we had a good variety of gin-poles, winches and adapters for different towers.

Spar, we run a sheave at the bottom as you've suggested.  I like to have the ground-folk get a wrap or two around a truck-pull or tree when it is anything heavy, like this - as I lift, they also can pull and take-up slack, so it should be quite manageable.  I've never had a capstan; wish I did.

Here's the gin I adapted to fit this turbine.  It works great because it is light, but strong and the top pivots and locks in any position:




The weather is turning again.  We got another 6-7" of heavy wet snow today, and now it is supposed to get colder.  But, this weekend was warm and mild, so except for some fog and early ice on the tower, I was able to get the gin set and take the blades off.  Doesn't sound like much, but it is so much easier if it is calm.



I think the hub assembly is roughly 5" deep, so I'd need this and enough clearance to get at the rear bearing, but I'm still thinking the stator can just drop down a bit and sit on these spacers:

[Mary B]

Yes, that's right.  Neil, my long-time climbing buddy and I erected lots of towers, and set, and took down many turbines back in the day.  We almost never had a crane, but we had a good variety of gin-poles, winches and adapters for different towers.

Spar, we run a sheave at the bottom as you've suggested.  I like to have the ground-folk get a wrap or two around a truck-pull or tree when it is anything heavy, like this - as I lift, they also can pull and take-up slack, so it should be quite manageable.  I've never had a capstan; wish I did.

Here's the gin I adapted to fit this turbine.  It works great because it is light, but strong and the top pivots and locks in any position:
(Attachment Link)

(Attachment Link)

The weather is turning again.  We got another 6-7" of heavy wet snow today, and now it is supposed to get colder.  But, this weekend was warm and mild, so except for some fog and early ice on the tower, I was able to get the gin set and take the blades off.  Doesn't sound like much, but it is so much easier if it is calm.

(Attachment Link)

I think the hub assembly is roughly 5" deep, so I'd need this and enough clearance to get at the rear bearing, but I'm still thinking the stator can just drop down a bit and sit on these spacers:
(Attachment Link)

(Attachment Link)

Some warm weather in the 10 day... I am afraid of when it breaks and dumps feet of snow on us! Had ice fog this morning, my antennas were so loaded the 2 meter 20 foot long booms were drooping 3 feet at the ends! Lot of weight can build up fast!

[kitestrings]

That's got to be pushing the limits of things structurally... then you add in wind, and all bets are off.

[Mary B]

That's got to be pushing the limits of things structurally... then you add in wind, and all bets are off.

Wind will shake it off the ends of the booms and they spring back up, adds a heck of a lot of wind load to the tower! My worst was over an inch of ice, everything survived it but that was no wind and we had mid 20's and sunny days the next 3 days. Sun will melt it off even if below freezing. I did put a hard hat on and grab a telescoping painters pole and knock a lot of the ice off the ends of the antennas.

[kitestrings]

We got a perfect day Saturday to take this on.  Warm.  No appreciable wind.



I released the stator as planned.  There seemed to be plenty of slack in the Liquid-tight to swing it off the spindle.  Prepped for the lift.


The rope was down thru a snatch, then out to my (parked) truck where I had a clevis on the plow hitch with a figure-8 descend ring.  Adler, my son and I put about 150# of tension on the rope, and tied off.  No backing up now...


The rear bearing was toast.  I was able to pull it apart in pieces.  The one snag was the inner ring was ceased on enough that I couldn't remove it without a puller, and my longest puller was too short.  It had to come off, or we would need to lower the thing; high winds coming Sunday/Monday.  It meant a last-minute run to auto-parts store... losing daylight, but they had just the one I needed.

Here's the new bearing in place.


The 10-12" lift took two on the ground, and me lifting... a bit of jockeying and finesse, but we managed to land it, finishing by headlamp.

[SparWeb]

Do I see rust on that bearing?  Moisture snuck inside?

Ooh, you gotta sell tickets and popcorn at these events.  "Will KS and the team get the WT back together before the storm blows in?"  Or start a Youtube channel.

[kitestrings]

Rust.  Moisture.  Yes & yes.  It looked to me like the rear seal had allowed moisture in.  Maybe it gets too dry, or maybe there is condensation after running longer stints?  The seal was in place and the rubber looked good, but look at all the accumulation behind it:


This was the heavy lifting; pun intended.  We should be able to be up and running soon.  Crazy high winds today & tomorrow, but after that... it's looking good.  Colder, but much lower winds.

[bigrockcandymountain]

I'm always in awe of your climbing adventures.  It's such a cool thing to do with your saturday, and I bet your kids think you are superman.

I'm glad you found a smoking gun, and aren't left wondering what caused the failure.  And i think I can still like timken bearings, so that's always good.

+1 on the YouTube channel.  I'd watch that. 

[Other David]

 Hello kitestrings my name is David I've been looking for your post and spotted something that interests me but it's going off the topic of bearing. I noticed you produce your coils as individuals could I ask please how do you connect the coils together. Thank you very much
David

[kitestrings]

Hi David, and welcome to the forum.  Yes, we did individually potted coils, and we just brought the leads out to external studs where they are then connected with ring terminals and these little boots, kind of like spark plug wires.

https://www.fieldlines.com/index.php/topic,147846.0.html



Electrically it is like this (16-pole alt, 12 coils):



If you meant physically how are they connected, they have T & groove on the edges which holds them in one plane, and we now sandwich them between two Garolite stator rings.  The rings then attach to the stator bracket assy.

[kitestrings]

[kitestrings]

I just wanted to share a couple pics of this figure8 device that I mentioned (not from our actual lift).  Anyhow, I'm finding more and more that this is a pretty handy thing for different applications.  You can use it to cinch up, or lower, in controlled fashion, a very heavy lift/pull.  I didn't own one until 5-10 years ago, so I would commonly do wraps around something round, smooth... sometimes doubling back to a loop for a similar mechanical advantage.  This works better, and can be anchored more easily (than a tree that might not align well).  You can wedge the dead-end perpendicular under the rope to "lock it' (though I still wouldn't totally let go).  See:





I should probably also mention that at the top of this gin, there is the option to "dead end" the rope at a pin connection, and then introduce another snatch block.  This cuts the load in half on the rope.  In our case though, we didn't have much clearance to work with, and it also would move the lift point away from where we wanted to be - so a easy trade off.

More here than most folks probably care about, but I'm always fascinated when I cross paths with someone who knows rigging, climbing, rope/knot know-how; always like picking up new tricks.

[SparWeb]

I've rappelled down some cliff sides under those figure-8's.  It was a long time ago, of course!

When do they need the little horns on the larger ring?  I remember seeing those but never saw it used.  Tie off?

I saw these again, doing helicopter projects where the forest-fire fighting crews were rappelling out the helicopter door.  I was concerned with the heli, more than the ropes at that time.
By then they started using other devices which helically coil the rope inside a cylinder to achieve the same thing (but builds a hell of a lot of friction heat).

[kitestrings]

Yes, I've seen those too, but I honestly don't know what the application is that they are intended.  The rock-climbers, rescue and nautical folks have so much more knowledge when it comes to this stuff.  I'm usually like, wait, wait... what did you just do there.

Our snow took a big hit, but on the plus side, this unusual, extended warm spell allowed us to get everything back together - without weather events setting any limits.


On Sunday I seated the grease seal, reattached the stator and preloaded the bearing.  The stator was a snap to realign; much easier than a full dismantle.
 Yesterday my son and his SO helped hoist the blades to me. There were lots of surfaces needing to be de-greased (and no one else to blame).


...working bare handed on 12/26!  We're up and running, though winds are forecast to be modest at best until ~Friday.  At these speeds it is near silent(night).

[kitestrings]

Things seem to be working well again.  Here are a few random pics.




Today was a pretty good test... strong steady winds that started mid-morning.  We've logged about 4 kWh so far today; the PV was .5 kWh.  My latest power curve has the transition from the fist controller set a bit lower, and this works well.  Cut-in is ~58-60V on the first controller.  The second one wakes at about 70V now and starts to load up pretty good starting at about 86V, and topping out ~135V.  Hard to capture both at once with a still shot, but something like this:


We also have the load bank starting to pulse a bit lower voltage.  Keeps things calm.  Oh, Happy New Year. ~ks

[SparWeb]

Happy New Year to y'all too!

[bigrockcandymountain]

Looks good.  Good to see you back in business.  You got that fixed faster than I imagined you would. 

Did you do anything different with the grease seal this time around?

[kitestrings]

So happy to be up and running.  This is the time of year when we really rely on this thing.  I'm happy to report it is working well, very quiet, very smooth.  And, with our latest curve the two turbines are sharing more evenly; peak yesterday was ~2 kW on one and 1.5 kW on the other.

No real change other than new Timken bearings front and rear, & new seal.  I'm still using Chevron Ultra-duty EP.  I'm thinking that we should be pushing more grease thru this thing though.  Clearly some moisture got behind the seal, but some of what I cleaned out was dried out, sticky.  I'd been using my smaller grease-gun and I may just need to hit it more, and more religiously when I go up.  Perhaps just a pre-emptive replacement at say 3-years would avoid issues too.


We had two back to back storms that knocked out ~30k customers across the state within days of one another.  We had probably pushing 65+ mph gusts here.  I shut things down, shorted winds and lashed the tail just to be sure.  Phew.

[kitestrings]

Wednesday we logged 5.3 kWh, and I shut it down at 11 PM.  The first controller peaked at 1,976w; the second one was 1,565w, at an input voltage of 82VDC.  Yesterday the winds dropped off mid- to late day, but we logged 3.6 kWh, with 1,857w & 1,172w respectively at 78V. 

The peaks are not of super high importance, but I had been trying to shift a bit more off the first controller, and generally start limit the high-end speed just a bit sooner.  So far the highest I've seen is 2,242w and 1,425w at 124V.  I like this better.

[SparWeb]

You sure are spending a lot of time up that tower!

[Mary B]

Winter climbing on top of it! Did that twice, then decided I could live without that antenna working until it warmed up!

[MattM]

He certainly is proving wind turbines work in the cold.

[JW]