More bearing problems!!

[windvision]

Jarrod:

  Thanks for sharing. No one has asked, so I am assuming the grease used is up to the task. Any thought of running a synthetic grease or a grease capable of higher loads before breakdown? If it isn't the end play, or the fact it might be somewhat small for the job, I would take a hard look at the grease when you do the teardown inspection.  Good luck.

[zvizdic]

Type of grease is no issue.
You can use any grease or oil but if bearing is not up to load rating it is bound to fall .
In windmill application those hubs carry almost all load on one bearing and if it is 1.25" ID at-list use Timken or SKF bearings they are rated for 8000 pounds.
I like synthetic grease,high heat resistance is a god thing in a summer .

[fabricator]

high heat resistance is a god thing in a summer .

You got that right!

[niall2]

hi Jarrod

this is,nt really related to your post , as i got temped by using the "cheap" maintenance option

lately i had to again replace the bearings on my machine (much smaller)....

the new rear bearing i bought turned out to be a Chinese grey model ....i wasnt sure whether to use it and a friend suggested i wash it out with cleaner to see if  
anything "extra" was included in the price ...and have a rethink

sure enough after rinsing with carb cleaner there were  some steel filings (a small amount) left in the cup....you could pick them up to the side of the cup with a magnet
actually more like steel dust than filings  

but i wonder if bearing issues (choices)  dont get as much publicity as they perhaps might .....if the bearing starts to let go ..the air gap is compromised ?
its a good topic

my hub is borderline for the machine size.....but being a small mill  it,s easy to do periodic maintenance ....a 20 footer seems a totally different challenge though
 

    

[zvizdic]

Good  build machine require no maintenance for long time.
I picked my bearings having in mind that a Bridgeport mills ran for years and die whit good bearings.
New ones are 200$ each I got old ones (good for life whit one spare).

[jarrod9155]

Niall2 ,
  Your right about the inspection for fillings , and for the topic involving the stator being damaged that was really my whole reason for asking for a different way of building the axial flux alternator .
 

[Watt]

This hubs a rated for i assume  3000 pounds radial and your trust is all on one bearing .

Even a 7000-7500# spindle (#42) only uses like a Timken 1412 outer bearing with a 1.25" journal, which is too small for a 20 foot wind turbine.  If you get rid of the grease in the hub and go to oil bath like all heavy duty trucks use so you can run decent preload on the bearing set -  then it might take it for awhile.  But otherwise you're barking up the wrong tree and it will only last on a poor wind site where it doesn't get pushed very hard.
--
Chris

Just some thoughts.

These taper roller bearings on vehicles take a beating these blades can't duplicate very easily.  Take a fully loaded Ford, Chevy or Dodge pickup 2wd with these taper bearings installed in the front rotors or hubs with the truck laden load in the 12k plus pound range.  Hit a bump, turn a corner, hit the brakes while turning a corner or steer at high speeds while turning and applying the brakes in panic, bearings hold up well with nearly the same dimensions as these bearings installed on our axial flux alternators 6k axles as pairs.  These loads are tremendous.  As an inexperienced teenager, I wrecked heavy " boat " cars and bent spindles yet never had a bearing failure due to load.  My failures were due to improper bearing installations and once I learned " trial and error " to properly install bearings, I have yet to replace a bearing for reasons other than neglect/age. In this thread, I believe calling these bearing failures may result in yet another repair.  If nothing else, send them to the manufacturer for their opinion. 

[jarrod9155]

Watt , 
  I see your point on your view of weight but remember that when this turbine is in a 20 plus wind most of the load is straight forward not mostly pushing straight up do to the weight of the vehicle and these vehicles don't have stators right behind them that need minimum clearance . I have never had any problems in my boat trailer bearings and that has a 5,000 pound wakeboard boat on it plus the weight of the metal trailer thats combined close to 6,500 maybe more if the balast tanks aren't completely empty and I haven't had a falure on any of theses hubs .At  work everything is mostly wheel hubs now but a lot of the trailers I work are still hub and bearings and I haven't yet had a failure I can remember . What I am getting at is done Right to spec the hub and bearing on my unit with my winds isn't holding up no matter the tech working on it . I have never lived some were where you have to tie your  trampoline down to the ground or it will blow away like a piece of  paper I am on my third trampoline . Again I still believe trailer hubs done right are a great way to build a turbine  and if I wanted to stay with this design I would step up to a 5,000 plus hub and probably have minimum problems but a different approach would be refreshing .
Jarrod

[jarrod9155]

Chris , sent you a private message with my email thanks again .

[Flux]

As a matter of interest for someone the other side of the pond, what size bearings are used in these hubs. I saw someone mention 1.25" inside diameter in a post. I used that size on a 10ft machine and wouldn't to use it on anything bigger.

Also I see mention of how these stand a beating on trailers, yes loading wise it may be similar but the annual milage is small compared with a wind turbine running all the time, there run for an incredible number of hours. When you get near bearing limits it become a matter of stress cycles and hours affects this greatly. the low wind running may not hurt much but in high winds the stress cycles mount quickly.

Flux

[Dave B]

Jarrod,

  Do you know the actual RPM vs. wind speed that your turbines were running at ? Not the projected or programmed or estimated figures but the actual measured RPM vs. wind speed ? At 20' diameter the output of a "good" turbine could increase 1000 watts per every (1) MPH increase in wind speed from 23 MPH to 26 MPH. Possibly from close to 7000 watts @ 23 MPH to 8000 watts @ 24 MPH to 9000 watts @ 25 MPH to possibly 10,000 watts @ 26 MPH.

   Even at 20 MPH wind speed you could be close to 5000 watts and just (1) MPH more could put you up near 6000 watts in a blink of an eye. Just my gut feeling but I'm guessing your inverter and or load control is not putting the brakes on early enough or hard enough and soon enough to protect your system from running too fast for it's design.

 Any machine and especially the larger diameter machines running at high RPM with possible play in the bearings, a close air gap and iffy load control is going to have a short run with this current design I'm afraid.  Dave B.

[jarrod9155]

Dave ,
   Your right the inverter has had a hard time with these blades do to there torque . Rob Becker made a quick tune for the inverter but theses blades needed a lot more load and slower rpm compared to what he has worked with in the past . Luckily my furling with my current blades has been right on furling at 20 mph the max input the inverter has seen is 3100 watts , a day last week it stayed constant around 1,800 watts all day in out of furl some times staying furled for minutes at a time . And before I had time to change the tune from the old 18 foot to 20 foot blades they were really moving it's a guess but I would say 250 rpms was the max rpm the blades see . I use the voltage and hz to figure rpm and at 3,100 watts i am seeing 220 rpms witch is 200 volts dc in the house . I have had no problems in the past braking the mill with just the stator even with the big blades but thats also having a tight air gap that in return bight me every time when it rubs . This time it completely wreck the nicest stator I've built yet . Really I should of lowered it and waited on fixing it but in staid I raised it back up and now I'm starting over .
       Short answer is no I don't know actual wind speed at the time of reading rpms or voltage my wind speed devise is a cheap home depot unit with 6 second delay wireless .

[Watt]

As a matter of interest for someone the other side of the pond, what size bearings are used in these hubs. I saw someone mention 1.25" inside diameter in a post. I used that size on a 10ft machine and wouldn't to use it on anything bigger.

Also I see mention of how these stand a beating on trailers, yes loading wise it may be similar but the annual milage is small compared with a wind turbine running all the time, there run for an incredible number of hours. When you get near bearing limits it become a matter of stress cycles and hours affects this greatly. the low wind running may not hurt much but in high winds the stress cycles mount quickly.

Flux

Flux

I will be happy to get the bearing size this afternoon.  For the ' 1.250" ' bearing, that would be the outside bearing of the smaller 5 lug or 4.5" to 5" - 5 bolt circle hub and still the smaller of the two.   On the 3000lbs rating per hub 6 lug units most of us here in the U.S. are Loading, both bearings are near the same size and much bigger than the hub referenced here. 

Another added thought:

As mentioned earlier on in the thread by someone: on a vehicle, the load is mostly fixed and downward.  Well, my thought on this is: this type load mostly loads only a few or so rollers in each bearing while a straight on wind load would mostly load and distribute the force on all rollers in the bearing set.  So, if the contact area of the bearing cone face is damaged, I would doubt any damage related to wind load.  However, if the roller retaining edge of the bearing is mostly the only damage reference, this may be factually related to wind load. 

[ChrisOlson]

These taper roller bearings on vehicles take a beating these blades can't duplicate very easily.  Take a fully loaded Ford, Chevy or Dodge pickup 2wd with these taper bearings installed in the front rotors or hubs with the truck laden load in the 12k plus pound range.

That's not the issue.  Any wind turbine installed in a good wind area runs 7,500 hours a year.  Using the 36 mph average used in the trucking industry that's the equivalent of putting 270,000 miles a year on your truck at about the same rpm (figuring 600 wheel rpm on a 16" wheel @ 55 mph)

There are few, if any, TWD pickups with grease packed front bearings that will run 270,000 miles between service intervals.
--
Chris

[zvizdic]

And they got a good bearings in a hub, put a Made in China bearings 20-30 mph they are  kaput .

[Watt]

These taper roller bearings on vehicles take a beating these blades can't duplicate very easily.  Take a fully loaded Ford, Chevy or Dodge pickup 2wd with these taper bearings installed in the front rotors or hubs with the truck laden load in the 12k plus pound range.

That's not the issue.  Any wind turbine installed in a good wind area runs 7,500 hours a year.  Using the 36 mph average used in the trucking industry that's the equivalent of putting 270,000 miles a year on your truck at about the same rpm (figuring 600 wheel rpm on a 16" wheel @ 55 mph)

There are few, if any, TWD pickups with grease packed front bearings that will run 270,000 miles between service intervals.
--
Chris

Agreed, with the exception to loads during that service interval and the fact these type bearings have a century of miles.

I have two 2wd Ford f450 service trucks " mentioned 2wd due to having grease packed taper roller front bearings " in my field service fleet with more than 450,000 miles each.  Each one has an annual mileage of +100k and each one has yet to have a bearing failure.  These trucks are beat to death down country roads here in West Texas in the oil and gas industry.  While very well maintained, packing front bearings only happens near annually and each are still on there original set.  My f550 is an 08 and with 200k on the ticker, I have yet to replace its bearings.  Now, on the other hand, I have Chevy 2500 and 3500 4wd's with the sealed front bearing assemblies.  All of these trucks have required bearing assemblies before 100k and before the next 100k on the ticker if oem bearings are not used as replacements.  These Chevy bearing failures seem to be due to the roller " ball " type bearings as they are not tapered. 

[ghurd]

I have or had a few Toyotas.  No clue as to the size.

96 Camry, 290,000 miles, all factory bearings.  Regreased the rear bearings at about 275,000 because of a strange noise that turned out to be rust on the drums.
96 Tacoma, 180,000 miles.  The brake shop may have greased something before 90,000, but not after.  Usually has about ~700 pounds in it.  Need to trim that down soon.
99 4WD 4-Runner (that's a big one, larger than the Sequoia). 135,000 miles.  Never changed the brakes or greased anything.  Got it with a lot of miles, so not sure about the history.
92 PU (Tacoma?), near 200,000 miles when I sold it, shop greased at 100,000 miles with the brake check?
89 Camry, rusted to an early death, 165,000(?) miles, never greased.
86(?) PU, same as 96, about 185,000 miles when sold.

The trucks were in some rugged boondock places.  Not often or many miles, but water deeper than the doors were tall regularly, and more than one bullet hole.

Back when I drove 70-ish Beetles, REAL Beetles with no radiator and the motor in the trunk, I changed the bearings more often than the brakes.  Most were roller bearings.
Not a fair comparison because most of the Vdubs were junk when I bought them.
G-

[ruddycrazy]

Hi Jarrod,
             I came up with a design ages ago for a large wind turbine and got the guys at Timken to put my design thru the paces, the response was although they aren't into wind turbines the design is sound. Essentially the design is a full complement bearing as the front bearing which will take all the radial load then a dual tapered bearing for the rear to take the axial load. For your 20' blades I would look at a 75mm (3") shaft and get a machine shop or use a decent lathe to machine the shaft and hub. Also it would be worth buying a matched tapered bearing set for the rear bearings. I did work repairing industrial gearbox's for 5 years and do have a sound knowledge on bearings, the trailer hubs and simple facing tapered bearings can withstand upto a certain load but after that forget it. I can come with up a concept drawing if your interested and the guys here can agree or throw it down. Anyway with my 4kw motor conversion I upgraded the shaft diameter to 1-1/2" and I'll use a dual roller bearing for the rear. I did think about re-designing the bearing arranegemt but I'll only be putting 16' blades on and have a drum brake as well as furling to keep thing in check.

Cheers Bryan

[Janne]

Hi Bryan,

Since you're the native bearing expert here... What would be your take on using a pair of spherical roller bearings for the main shaft? It would make building the frame easier, as they would forgive any minute mistakes in aligning the bearing blocks.

[jarrod9155]

Bryan,
        What I ordered last night was 1-1/2 3 foot long keyed shaft with matching 4 bolt flange dayton bearings one for each end with matching couplings and split rings to keep the shaft in place .
        The modifications to swap over my blades  and magnets will be minium ,but I will redesign my whole windmill structure tail and all . I really like this idea so far it will be easy to service and it will desplace the load across the shaft I am thinking of about 2 feet between each bearing and the stator will mount in the back and blades in the front ,this design will use no automotive parts trailer hubs or car hubs . I hope this will allow me to keep a real tight air gap with out the worries of flexing .I am even thinking of adding a disc brake to the shaft for extra brake ,there are couple good deal on eBay includes disc , caliper , resavoir just need to add a actuator of some sort . Hopefully this weekend I can post some photos of it .
         I think this will be a great way to compare the two designs and even this setup can be done in average garage of diy that build the home-brews  . And again I think the the home brew designs are a great setup don't any one think I'm trying to reinvent the wheel here just trying something different that  I can give  some great feedback on good or bad .

[Flux]

There is a good case for separating the prop from the alternator with this type of bearing scheme. It lets you increase the distance between bearings and frees you from a few other limitations. The big virtue is that any mechanical failure will not wipe out the expensive alternator.

With your facilities you will no doubt make a very decent machine and I look forward to seeing your ideas. I am now convinced that the hub you were using is just not up to the duty, the scheme can be upgraded and made to work but your new approach will be fine. Just watch that you don't make too many dimensional changes that will compromise the furling, which you seem to have got right at present.

Flux

[jarrod9155]

Flux ,
    I like Chris idea with using springs and dampeners for furling ,I will increase my offset of the hub from the yaw bearing, I would like to run a smaller tail so I will be starting from scratch in that area . I think right now my tail ways around 70 to 80 pounds .
 

[jlt]

I used a 2 inch piece of exhaust tubing  For the tail boom on my 12ft . It seems to Pretty stiff and lite.     As for springs  to set furling . In my opinion They are more trouble than they are worth.     

[ChrisOlson]

    I like Chris idea with using springs and dampeners for furling ,I will increase my offset of the hub from the yaw bearing, I would like to run a smaller tail so I will be starting from scratch in that area . I think right now my tail ways around 70 to 80 pounds .

Jarrod,

If your furling has been working good the way it is, before you completely disassemble your machine place it on a stand in the shop and have a helper hold the tail stationary.  Push on the front of the blade hub with a scale of some sort, inline with the stationary tail boom, and measure the lb force it takes to furl the machine.  If you do end up going to a spring furling mechanism it will give you a starting point for the particular rotor and generator combination you are using to set your furling pressure.

I'd think twice about adding more offset.  If the machine has been furling the way it is you'll find it a lot more adjustable with a spring system and I think the amount of radical offset being used in some of the homebrew machines is due to the fact that it's difficult to get the tail light enough for the angled hinge system to work without a lot of offset.  That problem is pretty much non-existent with a spring system.

The size of the tail also makes little difference with a spring system as long as you don't get the fin so small that it takes a lot of angle of attack for the fin to make enough lift to steer the rotor.  A longer tail boom will provide satisfactory control over the rotor steering with a quite small fin.  On my 12 foot machines I've been using 8 square feet with a fairly long boom and they track the wind perfectly and steer very nice.  If you increase the offset too far the machine will be tracking up to 30 degrees off the wind direction without a radical tail offset, and you'll lose out on power.  On my 12 footers I only got 5.75" and it only takes 26 lbs of spring pressure to control the furling.
--
Chris

[fabricator]

Flux ,
    I like Chris idea with using springs and dampeners for furling ,I will increase my offset of the hub from the yaw bearing, I would like to run a smaller tail so I will be starting from scratch in that area . I think right now my tail ways around 70 to 80 pounds .
 

I used around 12" of offset on my 17' machine, HUGE mistake, no matter what you do you will always be 10-15 degrees of the wind, if you use a version of Chris's spring furling you won't need much offset.

[fabricator]

I used a 2 inch piece of exhaust tubing  For the tail boom on my 12ft . It seems to Pretty stiff and lite.     As for springs  to set furling . In my opinion They are more trouble than they are worth.     

What experience have you had with spring furling?

[DenisGCroombs]

I used around 12" of offset on my 17' machine, HUGE mistake, no matter what you do you will always be 10-15 degrees of the wind, if you use a version of Chris's spring furling you won't need much offset.
[/quote]

Hi fabricator
What offset would you use on a 17' machine ?

Thanks
Denis

[fabricator]

I used around 12" of offset on my 17' machine, HUGE mistake, no matter what you do you will always be 10-15 degrees of the wind, if you use a version of Chris's spring furling you won't need much offset.

Hi fabricator
What offset would you use on a 17' machine ?

Thanks
Denis
[/quote]

I'm building a 16' 4/1 gear reduction machine right now, it has 8" of offset, I think you'd be better off with something more like that, that way you don't need to run the tail at a goofy looking angle to get it to track the wind decent.

[ChrisOlson]

What experience have you had with spring furling?

Spring furling is fine.  But the winter and summer furling in the blizzards and thunderstorms is a lot more impressive.  LOL!  I couldn't resist that one  

For Jarrod - this photo sort of shows the angle at which the spring pulls on the tail control lever



If you move the anchor bolt to the rear it can be adjusted so it either just about, or does, go over center and "latch" at fully furled to shut the machine down automatically in very high winds.  If you move the anchor bolt to the front it can be adjusted to act more like a governor and get Bragging Amps in high winds.  And, of course, it can be adjusted anywhere in between too.

There's a series of holes in the tail control lever too.  Moving the spring anchor on the lever towards the hinge reduces max power, moving it in each hole progressively further from the hinge increases max power.

I've gone to the different adjustment holes to adjust it instead of using spring preload.  I now only use one spring - a Hillman #67 rated at 10.9 lb/in and 44.12 lbs max load - and I adjust it so it has 1/4" preload with the tail lever pulled up against the stop.

I still have one machine flying with one of the compression spring cylinders I used to use too.  Those also work fine but it was a lot of unnecessary complexity.  One day I walked in the beef barn and happened to look at the spring that has pulled the door shut for over 20 years.  That spring is so covered with fly crap and dust and rust that you can't even tell that it's a spring.  But it's been pulling that door shut countless times over the past 20+ years, pulling on a big staple drove into the door and it just works.  So I decided it if works there, it will work on a wind turbine too with a lot less machining time building cylinders and such.
--
Chris

[jarrod9155]

Thanks for the pointer on offset , I have always hated that the blades were 10 to 15 degs of from the wind and if I can get them more straight on with the spring system than I am more all for it . I like the idea of using a scale to find amount of pressure needed to furl using the old setup as a base .
    I plan on starting the new mill  tonight .