I lost my new blades to a wind storm.

[Bruce S]

Workbench magnets....

They start by drawing in random wrenches, loose bolts, and cans of WD40.  No surprise at first, magnets do that.  Every bench seems to have them, but you can't see them.  Soon, paint cans and margarine containers with odds and ends begin to appear, and you start to wonder about these workbench magnets.  Stuff covers less that half the bench top so it doesn't bother you much.

Months layer, you walk into the shop and realize the workbench magnets have accumulated a half-finished roll of poly tarp, a power drill battery charger and a box of hardwood molding offcuts.  You now question if these workbench magnets are breaking some law of physics or an invention you should patent.  There is still nearly 2 square feet of workspace, so it slips your mind after you finish whatever project you are working on, like painting a doghouse or sharpening the lawnmower blade.

After a year you have learned to live with your workbench magnets, and you manage to complete a couple of new chairs for the kitchen using the 13 square inches of flat space that remain.

Workbench magnets seem to be installed in every bench and table in my shop.  Even sawhorses and 10 gallon pails seem to get Workbench magnets after spending time in my shop.

I visited my Dad last week.  Ever since he retired the Workbench magnets have gotten into his boat and pickup, because they are now filled with random stuff too!  We have to find a way to remove or block these Workbench magnets.

This theory explains the JRA (Junk Reproductive Activity) particles that seem to constantly arrive at my work desk.
No matter my attempts to send them to the outer reaches of the 5th element universe the "STUFF" that somehow reappears each morning.
I'm going to attempt to thwart this phenomenon by improving the broom and box method of retaliatory pile-ons 

   

[Mary B]

It applies to desktops too... especially ham radio desks... mine is covered in tools, connectors, zip ties...

[tanner0441]

Hi

They are world wide as well. Totally international. We have them in the UK I spent a week being brutal and tidied my workshop and covered work area, 5 binliners went out. I was impressed, my wife was impressed I even sent a couple of photos to a friend and he was impressed. It is now some 6 months later I recently had to clear an area to put a small rolling mill and anvil made from a piece of railway track on my bench, there does always seem to be a small area round the vice with the bench exposed.

Strangely you can find things easier than when you have them all neatly in the drawers..


Brian

[DamonHD]

What's this "neatly in drawers" concept, please?

Rgds

Damon

[Bruce S]

BRCM;

Just wanted to stay thanks for letting us go on yet another well known tangent  .

We are all watching your quick recover. Looking for the continued updates

Cheers
Bruce S

[DamonHD]

Oh yes, definitely my fault this one.  Please and thank you and sorry not sorry.  %^P

(Actually, my tiny desk is tolerably empty and neat right now, but we can gloss over that...)

Rgds

Damon

[SparWeb]

Actually, BRCM, once we figured out you had your problem well in hand, like you always do, then the herd of cats felt free to do its thing.  I'm glad I was there to encourage them.

doncha love when 3 moderators in a row defend themselves for off-topic wanderings?  I just had to pile on.

[bigrockcandymountain]

Ha ha no problem.  I definitely encouraged this one.  I was hoping someone had some sort of "demagnetizing" device that works for a work bench.

The turbine is back up and running, and making good power.  The old rotor performs the same as it did before. Kind of noisy and not very balanced at low rpm, but makes decenr power.

The yaw is nice and smooth and light, but no better than before the bearing damage.  I think it all happened at the same time as the blade failure. 

The head must have jumped up about 4" and the ball cage flipped perpendicular to the races and jammed and bent.  The head assembly must weigh 300 lbs, so quite a force to make it jump.

[Bruce S]

The head must have jumped up about 4" and the ball cage flipped perpendicular to the races and jammed and bent.  The head assembly must weigh 300 lbs, so quite a force to make it jump.

Holy Moly!! 300lb moving 4inches and what TSR??
This would be Mother Nature reminding us how insignificant we are.
Glad to read it's back up. You getting enough to run the workshop & house again?

Cheers
Bruce S

[bigrockcandymountain]

Hey Bruce, looks like i missed replying to this one.  Yes. The old #2 set of blades kept us in power until yesterday. 

Yesterday, the tail unfurling spring broke, and the turbine shut down.  I thought it was a good excuse to put the new blades (4th version) up.  They have been hanging on the shop wall for months.

They are up spinning now and making power.  They are better balanced, and start up a touch better than the version #2 that were up there.  They might even be better than the version #3 that broke. 

I haven't really got good numbers from them yet.  They were making 250w in some pretty light winds yesterday. 

As always, I didn't take as many pictures as i thought i should
As you can see it took a fair bit of weight to get them balanced. 
The hub got extended ears made out of 3/8" steel plate.

I also have the power furling project on the go, but I'll save that for another time.

Specs on these blades.
13' /4m diameter
2x8 spruce lumber so 1-1/2" x 7-1/4" at the root
4" wide at the tips
They are about a 20% thickness flat bottom airfoil. 
3deg pitch at the tips
11 deg at the root. 
The pitches were set much more carefully than before.  I think this helps balance. 

[Bruce S]

Nice view up there too!!

[SparWeb]

The pitches were set much more carefully than before.  I think this helps balance.

Aerodynamic balance, yes.  Just as important as mass balance.

[kitestrings]

I like that the failure mode - you're spring breaking - results in the turbine shutting down.  Usually when something breaks there's hell to pay.

Looks like some icing on the blades; cold there too.  We had a few record warm days last w/e, but we're back to building fires again at least at night/early AM.  Looks good.

[bigrockcandymountain]

It has been another fairly cold april here. It was raining/ice pelleting the day I put that rotor up.

So far, I'm quite happy with these blades.  They made 15kwh one day this week.  Most days they made about 6kwh.  It has been quite calm lately, so not bad production.  The peak power is also better.  They seem happy to make 2kw where the old rough ones struggled over about 1400w. 

They run smooth and start up better than any set so far. 

The only complaint so far is an annoying high pitched noise at low speed.  Maybe a corner of leading edge tape is loose or something.  It's not a huge deal, just kind of an ugly noise.

[MattM]

Hopefully not the sound of a flat spot in a bearing.

[bigrockcandymountain]

No, at least I don't think so Matt.  The noise changed as soon as i put the new blades on.  The bearings still feel really nice. 

I don't think I ever took pictures of it because I'm usually covered in grease, but the motor bearings have grease fittings.  They also have drain plugs on the opposite side of the bearings. So you take out the plug, pump new grease in one side and it pushes old grease out the other.  Kind of like an oil change for the bearings.  I think they should last a long time if i keep up with the maintenance on them.

We had a strong wind last night.  I saw over 2kw on the meter, plus whatever power the clipper was dumping.  Probably some 3kw peaks.  I shut it down because i wanted to sleep and not worry.  It all seemed like it was doing fine though. 

[Bruce S]

BRCM;
Once it gets up to cut-in speed does the high-pitch go away slowly or does it just drop away?
IF it's just going away, I'd still be looking at a bearing. Those types of whines sound similar to how wheel bearings get to sounding.

Cheers
Bruce S 

[bigrockcandymountain]

I bit of an update on these blades.

Bruce, I would say the noise cuts out abruptly at a certain speed. I won't rule out a bad bearing though. They took a pretty good thrashing when the blades broke. 

The new blades were mostly ornamental for the summer.  The last few days I have been using the turbine again, and they perform like they did before. 

I did some work on power furling during the summer, and it finally all came together yesterday.  I can now turn it off with a switch in the basement.

I did all the trenching by hand, so it was good exercise.  I'll go up in the next few days and take pictures of the actuator installed. 

[mbouwer]

Is it a hard ground to dig into?

[bigrockcandymountain]

I can definitely relate to the picture.  There were a couple times that I doubt i could have found a dry spot on my shirt.  I trenched the main cables down with a chain trencher, so it was disturbed soil.  Not the hardest digging, but not easy either. 



I didn't exactly make a pretty job of it, but it works as it should.  It takes about 30 seconds for the actuator to cycle.

[Bruce S]

Gotta say, the view is awesome!!
Biggest issue we had last week was the humidity. Can't sweat out when the air is as high as the temp.
Drank so much water even it got to tasting bland. Gatorade-ish to the rescue.


Cheers on getting it sorted out!!
Bruce S

[Mary B]

View reminds me of the top of Buffalo Ridge near me...

[kitestrings]

The next time you don't have to hike up that hill in a violent storm, it will be well worth it.  Congrat's.

I vaguely remember the set up.  This cable goes to a pair of ears that extends below the sliding tube IIRC.  What I don't remember is, does the mechanism furling our open the tail when you pull down?  I was thinking your default position was that it was furled.

Best, ~ks

[bigrockcandymountain]

No, I wanted to make it as a "pull to turn on" but couldn't seem to make a plan work.

As it is, it is "pull to shut off".  And yes, you have a good memory.  The swivel is up at the head, with a pair of ears and sliding haf tube setup.  It all works nice up top.  I'm thinking I'll make a lot better use of the turbine now too.  There are always those days that you could maybe use a bit of extra power, but the weather is supposed to get ugly within a day or two, so I leave it off.  Now I can easily turn it on, even if it is only for an hour or two. 

Thanks for the encouragement.  Your slick setup is what got me thinking about this upgrade.

Now I just need to add a relay triggered by the classic to make it automatic.  Or maybe I will use a voltage monitoring relay.  I have one of those too. 

We get more than our fair share of freak ten minute wind gusts when cold fronts blow through and lots of times, they aren't forecast.  Automatic would be a good thing. 

Ya. the hike is worth the view that's for sure. I have lived here my whole life, and i still stop and admire it every time I'm up there. 

[kitestrings]

You mentioned bearings - our turbine recently developed a noise; one per rev.  I went up just to inspect, and found some noticeable end-play at the blade tip.  We had this once before, but I attributed it to one of the races just not being fully seated (and I had just replaced them both).  It seems unlikely this would have happened again, but I'm not sure what else it could be, short of a full-out failure of a cage.  Any thoughts?  (Sorry to drift, I can take this to another post if you prefer).

[bigrockcandymountain]

Maybe with a slight bit of end play your rotor is just shifting back and forth or side to side within the play of the bearing due to a bit of imbalance. 

Your bearings are tapered roller bearings if memory serves.  As long as they have grease, they will still roll when in pretty bad shape.  They usually only seize when they are dry. 

If it was me, i think i would just keep a close eye and ear on it  and see if it gets worse.  The geometry of tapered bearings makes a small bit of wear in cause significant play.  Trailer wheel bearings can  have quite ridiculous play in them, and not do any harm. 

Here is what happens when they don't get oil. 

[topspeed]

How do you ensure they do get oil ?

[JW]

Are you using 90wt gear lube. if so add a synthetic viscosity additive. something like lucas oil stabilizer.

 

 

[bigrockcandymountain]

This one was on an old john deere loader backhoe.  The lube port to this bearing was plugged with a little piece of something about the size of a pencil lead. 

I got the machine cheap, and lucked out that this was all that was wrong with it. I thought the powershift was toast.  I did all the machine work, since it spun and chewed both the inner and outer race.  I think total parts cost was under $200. The new oil cost more. 

It runs a low viscosity gl4 oil that is usually called TDH or tractor, differential, hydraulic. 

The sideways rollers at the top are welded to the inner race.  It was quite a mess.

Kitestrings, is it just a very small bit of play, or enough that it clunks back and forth pretty good? What is your method for setting bearing preload?

I don't mind this discussion on here, but if someone thinks it should be moved, that's definitely ok too.

[kitestrings]

I think it is pretty small.  I didn't have anything to measure when I was up there last, but I might estimate maybe .375", probably less, at the tip.  And, it is only about 2.5" between the bearings IIRC.  If that were true, and my quick math accurate, it might be .010" at the spindle.  I'm thinking a flat, or two, max two would correct it.  I just hope that's all it is, right.

My habit is to always move a vertical blade in/out from the tower each time I climb.  It's just more than there was, and the noise above a certain speed had me concerned.  I think I read somewhere that the human hand can feel things down to minute difference (less than half the dimension of a hair), like a divot from a pen on a pad of paper.  This is not precise, but it's interesting I think how we assess allowable tolerance, largely by feel.

[kitestrings]

Oh, the method…

I’ve been following the Timken guidelines, which are:

Want .001-.005” end play

1) while rotating rotor, torque to 50’#
2) loosen one full turn
3) continue spinning & toque to 10’#
4) back off 1/6 to 1/4 turn

Perhaps 50’#, or the 10’#, is not enough with the weight of the rotor on the hub?

[JW]

 

Oh, the method…

I’ve been following the Timken guidelines, which are:

I would just like to say for the record I hate Timken bearings because they do not handle thrust loads well.  Under such coditions they overheat and clearance get to tight.

[kitestrings]

Is there one that you feel is notably better?  If so, how/why?

It doesn't seem like we are spinning anywhere near fast enough to have heat be a measurable factor.  On a car the hub might be regularly turning 600-80 rpm.  On our turbine 250 rpm is pretty fast.

Chris O. had some interesting critique of tapered roller bearings in this application:
https://www.fieldlines.com/index.php/topic,145925.msg1019269.html#msg1019269
https://www.fieldlines.com/index.php/topic,146180.msg1000338.html#msg1000338

It seems like the issue of sitting for long periods, where the lubrication cushion is lost could be real.