Author Topic: Furling (Read 3795 times)

97fishmt · « **on:** March 19, 2010, 01:14:54 PM »

And the day after the big winds and snow.

Do you think I have flagging going on?

fabricator · « **Reply #1 on:** March 19, 2010, 02:41:25 PM »

I don't know about the flagging thing but you live in one of the most beautiful places on the planet.

SparWeb · « **Reply #2 on:** March 19, 2010, 03:50:42 PM »

We are all VERY ENVIOUS.

freejuice · « **Reply #3 on:** March 19, 2010, 03:51:56 PM »

yep, that tree is bent and pushed to one side.

Make sure you keep that hat on your head... if not you might find it 800 feet down the hillside

bj · « **Reply #4 on:** March 20, 2010, 06:30:04 AM »

Had to give my head a shake to remember what the post was. Beautiful area, nice shots. Being a flatlander, I always appreciate shots like that.

Back to the post, looks like furling is happening. Does it seem to be consistant? Nice tower too, by the way.

97fishmt · « **Reply #5 on:** March 20, 2010, 10:26:11 AM »

Not in constant furl. It is working like it should,

turns out of the wind with pressure on the rotor.

My issue I had in my last post was that it was furling

to far and the blades would stop. Not what you want

with a wind turbine.

Someone posted a comment on a Bergey Excel about the

tail was only allowed to go to about 75 degrees when

it was furling.

This was what I wanted to try first, limit the tails

travel to still produce power in stronger winds.

I also gave the tail a little more negative angle at

the at rest position. So the tail points the machine

into the wind to be more affective at starting the

balance between pressure on the rotor and gravity

of the tails inclined hinge.

The results so far are a very safe and smooth machine.

It doesn't slam the tail around and the tails action is

nice and smooth letting the machine work even through

high winds and still producing power.

It was like watching it dance, poetry in motion when I was

getting some high winds. I am so happy.

97fishmt · « **Reply #6 on:** March 20, 2010, 11:27:50 AM »

Look at the bending on this tree.

http://www.fieldlines.com/images/scimages/3510/grandpa_tree.JPG

I call it the grandpa tree.

97fishmt · « **Reply #7 on:** March 20, 2010, 11:43:02 AM »

http://www.fieldlines.com/images/scimages/3510/above_clouds.JPG

Sometimes it's cool to be above the clouds.

It's like a sea of clouds with islands all around.

When the sun heats up the air and they all evaporate

the wind comes charging up the mountain.

Usually I am dumping lots of power when it's like this.

The solar power and wind is a bit much some times.

This is when I turn off the turbine sometimes.

Ronnn · « **Reply #8 on:** March 20, 2010, 02:44:43 PM »

Looks mighty familiar like N.M. [where I am at 7k feet] or AZ or Co. Sometimes I'm surrounded by low clouds with just me and Carizo peak @11k feet sticking up out of them. NIce tower. What size is your genny? You mentioned a negative angle at the rest position. By rest do you mean pointed into the wind? I'm pretty new to all the lingo but I learn something here every day. Back to the angle, is it a homebrew genny? If not what was the angle when you started and what did you change to. Nice pics and nice work on dialing in the nice performance.

Ron

97fishmt · « **Reply #9 on:** March 20, 2010, 03:15:13 PM »

Hi Ron,

I'm only at 4500' and that's Mt. Bonaparte at 7200' but the valley

below is at 2500'. So lots going on when air temps change.

My big challenge now is to make damn sure I get my lightning

protection up to date.

As far as the tail stuff I started off with the tail angled straight

back from the back of the alternator and let it rise on its hinge

past 90 degrees.

Changes were made to both points. Let the tail drop further past

straight back (negative) and limit its high point before 90 degrees.

Hope you can share your builds with us. Thanks for the comment.

Dave B · « **Reply #10 on:** March 20, 2010, 05:01:33 PM »

It's great to see you worked on your furling and you are happy. Like a dance you say, I know what you mean.

It is interesting to read of all the new ideas (and I wish those trying the best of luck) for furling. It is too bad that a few unexpected results of the furling has created such anxiety that many feel the need to change the gravity furling tail completely.

I did not fall into getting it right but I sure had no plans to try to re-invent the wheel from the most successful design out there so I worked at it.

A new design proven to work even today would take many, many years of real world performance to even start to be accepted as a better mouse trap. I'm sure it's out there but I would rather go with "up time" just like Bergey. If it ain't broke don't fix it.

Thanks for posting, those are great photos too.

Dave B.

97fishmt · « **Reply #11 on:** March 20, 2010, 05:41:53 PM »

Thanks Dave B

On my last tower the unit had a spring to keep the tail in the

into the wind position. When I made a new platform for the

alternator and more offset I knew I could try the real gravity

furling system. My spring setup worked good to pull it out in

gusty winds but it was slam bang kind of stuff. Ugly. And on that

smaller tower lots of turbulence.

I agree with you about just keeping it simple and making it work.

I have found setting things forward and keeping the gravity tail

with offset to work perfectly.

You will see me go larger with out a doubt.

97fishmt · « **Reply #12 on:** March 20, 2010, 06:10:06 PM »

Hi SparWeb,

Thanks for the comment, I know how wonderful it is.

I'd just like to say it was about 25F degrees outside

and 80F degrees inside just taking pictures out the

window. I have a nice getaway place huh? I just want

to share the fun.

Dave B · « **Reply #13 on:** March 20, 2010, 06:42:10 PM »

Yes, it just takes a bit of work to make things right. I am so glad you didn't think it would be easier or that you would be more likely to hit a winner first try with a new furling design.

Looks like a Rohn tower ? My machine is on an 85' Rohn 55G tower modified to tilt also very similar to what I see yours to be. Quad sets of guys on a triangular tower had me thinking for a while, again it looks like we worked that out similar as well.

Keep us posted and if you ever experience a visit from the wind seeking curse when building your larger machine (it could happen) you already know a little work and not garlic will send it on it's way.

Dave B.

97fishmt · « **Reply #14 on:** March 20, 2010, 08:12:18 PM »

You know Dave B. Whats going on. It's cool to share tales.

I plan to make some blades like you use, soon.

I don't think I need all the speed from lift on some of my projects

like most others, more torque and force to put into the battery is nice.

I like the slow sunflower look to a wind turbine.

SparWeb · « **Reply #15 on:** March 21, 2010, 08:11:33 AM »

Ah! Stop it or you'll have 100 neighbours before the year is through!

ChrisOlson · « **Reply #16 on:** March 21, 2010, 09:31:23 PM »

A new design proven to work even today would take many, many years of real world performance to even start to be accepted as a better mouse trap.

You mean like Jacobs with their spring loaded tail and variable pitch governor? When Joe and Marcellus Jacobs opened Jacobs Wind in Minneapolis in 1927 I'll bet they never dreamed that their machine would provide primary power for more farms than all other turbines combined. Besides being the most proven turbine on US farms, the "Jake" has run for over 50 years in remote locations Africa and in Antarctica with that furling system on it.

Bergey is a youngster in comparison and didn't show up on the scene until 1977. And if you read the Bergey manual you will find that they acknowledge that they know of situations where "Auto Furl" fails to work.

From their manual:

CAUTION!

Do not install the XL.1 wind turbine near cliffs or precipices or on sharp hills such

that the wind does not travel horizontally through the rotor.

Above that they explain how this can affect furling "and produce higher peak outputs" (translated to homebrew turbine jargon - a "burned genny").

When you use an angled hinge tail against gravity you can only assume that the hinge angle always stays constant no matter how much the tower flexes in high winds, that the airflow thru the rotor is always "clean" with no up or down drafts, and that there's no such thing as powerful side gusts (wind shear) that can down jet aircraft and cause wind turbines to run at full power fully furled.

All it takes is yet one more burned genny on a machine with the good old "reliable" angled hinge tail and we got another furling thread.

If it weren't for the experimenters exploring new territory the wheels of progress would come grinding to a halt overnight and the whole world would be stuck with the status quo. I've never been satisfied with the status quo.

--

Chris

Dave B · « **Reply #17 on:** March 22, 2010, 01:02:55 AM »

Exactly,

Copy the Jake or Bergey, they are certainly not new designs. I prefer to go with the less complicated for the home made machine and pick the youngster of only 33 years flying and thousands of machines worlwide.

I like experimenting as much as anyone and I have all the respect for those trying new things. Jacobs and Bergey were new once too but a new furling system proven to work today couldn't catch up to their success for at least 33 years and that would be if Bergey quit the gravity tail today.

It's all about what makes you happy. I am happy watching my machine perform as well as it does. To others this may be boring compared to experimentation and that's great, we get to see it all here.

Dave B.

ChrisOlson · « **Reply #18 on:** March 22, 2010, 07:07:24 AM »

My point is, if you use the Bergey-style furling system you have to design your machine and generator to handle those "higher peak outputs" that can happen. Bergey has more experience with that system than probably all of us put together, and they acknowledge that there's "issues". Does it work? Yes. Is it 100% exact? No. So if you design your machine around it as being an exact thing, you'll probably lose a stator or crash a turbine.

The one conclusion I've come to is that money and time spent on putting substantial copper density in your stator with a tail wagger is money and time well spent.

--

Chris

97fishmt · « **Reply #19 on:** March 22, 2010, 09:55:52 AM »

Sorry to get you guys jazzed up!

My alternators are very robust

and able to handle 5+ times what

I shoot for getting out of them.

The tower height solves most of

the turbulence problems you are

putting out there.

I've had my share of failures but

mostly they chalk up to just another

step in the right direction.

Please don't be offended. I'm not winding

stators. I'm using large motors made

for abuse, and lots of head room.

ChrisOlson · « **Reply #20 on:** March 22, 2010, 12:10:35 PM »

Oh, I'm not offended at all! I never get offended :-)

It's just that in the homebrew world I think a lot of stators get wound on the light side - and they burn up as a result when the furling doesn't work as expected. I think The Dan's build very robust stators, and anybody following their design parameters will not have a problem (or shouldn't).

But when you try to scale, say a 10 foot design, up to 16-20 feet and start dealing with huge changes in output with only a few mph change in wind speed, that has to be taken into account. The bigger the machine gets, the less room for error. I think that right around the 20 foot rotor size (Bergey Excel) you're at about the limit of where the furling tail can fail to work because things start getting too heavy.

I think this is evident in the designs by Bergey and Jacobs - Bergey plays on the small end with the Excel rated at 10 kW (7.5 kW for battery charging), while Jacobs plays on the higher end of consumer-level/farmstead turbines with the 31-20. The Bergey has become more popular because of cost. But of the two the Jake is the tried and true, and even Bergey recognizes this. Bergey says right on their website:

While it's cheaper to build a light-weight, fast-turning wind turbine, the history of the industry dating back to the 1920's clearly shows that light-weight turbines don't stand the test of time. The heavy-duty Jacobs turbines from the 1930's can still be found running today. Their light-weight competitors are long gone.

--

Chris

97fishmt · « **Reply #21 on:** March 22, 2010, 02:39:09 PM »

Well I certainly agree with you about building

much bigger and stronger and the effects on such

a large rotor.

I think when I get to that stage I may be looking

into the variable pitch control and definitely a

mechanical break. Thanks for trudging forward and

sharing your experience with the many followers.

Ronnn · « **Reply #22 on:** March 23, 2010, 10:54:57 AM »

Chris Said: I think The Dan's build very robust stators, and anybody following their design parameters will not have a problem (or shouldn't).

Chris, when you only know a little there are always more questions than answers. My area in central N.M. at 7k feet, is not a very good wind area. We often get serious gusts. The carport roof I built stayed in place for 20 years then one day it went sailing. So I'm concerned about over speed issues. We get high gusts as often as not. I will be using the metal kit from the Dans to be sure about furling. But if I wanted to add a little margin of safety, I get the idea that some extra windings wouldn't hurt.

If I were to do this, maybe winding two strands of smaller wire, how would that affect the performance of an otherwise stock homebrew 10 ft.machine? Start up speed maybe?

I'm only guessing, I don't have any practical experience to fall back on. Also would two strands of smaller wire with the same number of windings be appropriate or is more better. Same question regarding outcomes.

Ron

ChrisOlson · « **Reply #23 on:** March 23, 2010, 12:03:45 PM »

I don't have any practical experience to fall back on. Also would two strands of smaller wire with the same number of windings be appropriate or is more better.

When I've wound my stators I've found that using two-in-hand windings doesn't change the cut-in appreciably. But it adds copper density so the magnetic flux lines are being cut by double the strands of wire. Think of it as running two generators in parallel with the same set of magnets. So the amount of amps it puts out increases, and the power curve is a bit steeper.

So for that reason, I wind less turns with two-in-hand generators vs single strand or your blades will reach stall too soon. It'll cut in a tiny bit later, but that's not significant because there's no good power in < 10 mph wind speeds anyway.

On 24 and 48 volt generators you don't have to worry about this as much as with 12 volt. A 10 foot machine with a 12 volt stator requires two-in-hand windings to my way of thinking. Once you go to 24 or 48 volt with a 10 foot you can easily get by with a single strand of AWG 13 in a 24 and AWG 14 in a 48.

So if you're building an OtherPower 12 volt, I don't know what the plans call for as far as windings, but if it's only single strand you can ask DanB what they wind them with using two-in-hand with their blade style to make it work.

And if you live in a gusty area like you describe I'd definitely wind it with heavy enough wire so that you can throw the shorting switch any time and shut it down without burning anything up.

The other thing is blade style. The OtherPower design uses a lightweight, high speed blade style that's easier to stop, so it's not as critical as when using a low rpm torque blade that will turn a shorted turbine at 250 rpm and reduce the whole thing into a molten glob of copper.

--

Chris

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Author Topic: Furling (Read 3795 times)