Ametek motor fun

[mikeyny]

  The kids and I have been playing around with an ametek 100 v dc 5200 rpm motor. Starting out small, learning as we go. We have a 4 ft 8 inch diameter 3 blade prop. Believe it or not we made the blades out of some scraps of 3/4 osb plywood carved and shaped by eye, no specific copy of any other blade. We  had it flying on a fixed mount into the wind today,(no tower yet). We had very high winds in the fingerlakes today. (blades held up well so far). The best We could get out of it was 7 volts. I think we need about 500 rpm to get any usable power. We would like to get 14 volts. Should We make a 2 blade prop for faster rpm?  Our current blades are 4.5 inches wide from tip to root, tapering from about 1/4 inch think to 3/4 at the root. We have plenty of disposable blade material laying around to experiment with. I have some pictures and video that I may be able to post next week when I am back at home.

                                                   Mike

[ghurd]

Pics would help.

Seems like 4' 8" is kind of large for 700RPM cut in.

And really large for anything made of OSB.

Shorter is faster in the same design.

Might try 3' if you get bored.

G-

[mikeyny]

Thanks Ghurd, I may throw together a smaller set one nite this week. We got up to 8 volts today. It was going fast but a little out of balance. I am thinking about seting it up with a pully to gear it up. The high speed it takes to get any voltage out of it is a bit scary. Also I think my blades may be a bit heavy. So far we are having fun and may move onto something a bit better and bigger this summer.

                                             Mike

[mikeyny]

  Ghurd,

     Thanks for the help. I cut 8 inches off each blade. I also threw together a quick pivoting tower out of a couple 2 by 6's and a heavy duty door hinge. Now with the smaller blades we get much higher rpm. Up to 13 volts in high wind. (20 mph I think ?). Like I said before the high rpm is a little scary. Having the tower makes a big difference. I will post pics next week. I think I will try gearing it up to a 2 or 3 to 1 with some pullys and a shaft I have at home. I have also been looking at some of the furling info here on the site. We will experiment a bit to get it to furl when we want it to. My brother has a great wind site in the penn. wind gap so we may work our way up the learning curve and put up a usefull machine next summer. I think his wife is a bit weary of a windmill in the yard so we will probably put up a nice big heavy duty flag pole in the back yard with a flower garden around it for her ( and then sneak in a windmill when she is away.) LOL. I think I will be getting myself  one of hugh's book for my birthday this month. We also need to study up on some way of controling voltage and charging systems.

                                                     Mike

[mikeyny]

          Finaly some pictures. I hope I got them sized right. I can only seem to get one pic per post. this is a picture of the blade profile. The 3 blade prop is mode out of 1 piece of 3/4 osb including the hub.

[TomW]

This the one you wanted to show? Only other file was a .pdf that will not display in a page.

[popeye]

Hi, this is the first time I have commented on any of these forums. But after reading your post I coudnt resist.

  Without sounding too much like I am trying to sale something as much as I am just trying to help I would like to introduce myself. I make blades as a hobby and sale them. And my six footers make 1000 RPMs in 20 MPH winds. I have not found the top RPMs in my 4 footers, They easily make better than 2000 RPMs. These I have made out of wood and I have always chalenged anyone to find a faster blade than mine. So far nobody has. So far everyone has told me mine are the fastest.

  O.K. now for the advise. Dont gear it up. Just put a faster blade on it. For a first attempt your blades arnt too far off the mark. But a redesign is in order here, and it also looks like you have a sufficiant amount of skill to make a really fast blade.  

  For one your blade is way too wide. Make it 2 1/2" wide x five ft long x 1 inch thick. Any bigger than that is a waste of time. Make it a twin rotor so that the whole thing is one piece. This really simplifies attachment to the motor. And finally give it an airfoil. Because the airfoil is what is going to give you true performance. Wikepedia is full of this kinda stuff. Find a good airfoil profile and copy it. You can give your blade twist for added power but for a first attempt just make it streight. One tool that is absolutely a must need is the spokeshave. If you dont already have one then buy it. You will likely get hooked on making these and wind up useing it over and over again.  

[mikeyny]

Thanks Popeye,

           I will take your advice. And I may even take your challenge someday. I would love to see it spin as fast as you say (from far away) LOL. I have been doing carpenty and fine trim work all of my life, so I do know how to work wood. The spoke shave is one of my favorite tools. Most of the young guys laugh at me when I pull it out of the old leather sheath I keep it in and use it on the back side of some big crown moulding or other wood trim. So I will make a single blade, 5 foot diamiter. I will look up airfoil info and go frm there. I may do it this coming weekend , unless I go fishing in the good weather here. I will also be moving my makeshift mount further from the house, but maybee a bit lower. There seems to be good wind on the ground as well as in the air her. I will keep you posted.

[popeye]

     Hopefully my photo upload was successfull. This is a pic of the airfoil I use with good results.

  I know what you mean about the spokeshave being an object of joking on the job site. I have an old cordless drill too that I carry with me, bit an brace. I love that stuff and the only reason they tease us is because they are just jealous.

  I will attempt to upload a few more if this one works out.

   

[popeye]

[ghurd]

I hear they are too fast, too narrow, and very low torque, meaning they stall on some of the common PM DC motors, and have a hard time starting when they should with no load.

How many watts have you managed to get out of them?

G-

[popeye]

 Well what you heard is only a half truth. Yes they do have less torque than the wider blades but only at start up. Once they get up to speed they outperform the wider blade every time. The long narrow blade design is nothing new. In fact you can see them operating on every big commercial wind turbine.The design I use is borrowed from those. As far as stalling out on some of the common PMs out there I am guessing that you mean the 30 volt ametek or the 99 and so forth. These motors make 12 volts at very low rpms, and would need to be matched to the correct sized prop. For example my 4 footer is not a good choice for the 30 but is a really good match for the 38 so long as you charge with 24 volts or greater. My 4 footer gives me 50 volts open cercuit in 18 MPH with the 38. Many people have discarded the 38 for use as a suitable gen because they cant get it up fast enough. As far as watts go the 38 gives me 300 watts in 20 MPH.I try to keep in touch with as many of the people I sale to as possible. All have given me the same feedback. And that is for the same size comparison mine are better.  Now as far as the 30 goes there is a guy in New York that is doing some testing for me with my 6 footer. He owns every other blade that has ever been sold, including those wide aluminum ones, and from what he tells me is that mine has out performed them all. No official data yet, but soon to come. My own testing with the six has been brief because I do not have a suitable PM for it. But lets put it this way. In light winds it spins furiously. And when I short out the 38 it doesnt even slow. In fact I wanted to take it down because it had sold once the guy saw it working but I had to wait for three days before I got the chance. Sounds a little like Im telling stories here doesnt it? Air-x makes a blade that is only 1/2 inch at the tips and they produce plenty of torque. I know because I own one. Can you guys see my pics? Because all I see is a box with a little x at the top left hand corner. How do I fix this?
   

[ghurd]

All I have heard is from the buyers to whom I suggested may want to try those blades with Ameteks, Indianas, etc.

And I kind of feel bad about it.

Paraphrase quoting from the video.

(I still have it if you lost the link)

"The long narrow blade design is nothing new", like on the Air-X?

"Probably blowing about 12MPH right now" while showing 16V is not that great.

"Free-spooling" voltage doesn't mean anything.

"That slowed her down quite a bit" is obvious.

"Let me disconnect it from the battery, and alright, as you can see it is picking up speed real fast" is an indication of stall.

"If you do your math" infinite volts at 0A is 0W.

51V at 20MPH is about on track for a 36.  Nothing special.

However 300W with a short-version Ametek 36 is smoke in the making.

And 300W with a 4' dia prop in 20MPH is... (where is Ron when you need him?)... questionable.

You have a windmill, tower, blades, battery, Sperry meter...

Damn!  Why not just test the real watts of output???

I think the props look OK, better if they were from 2X4s.  

The price was good, if they are relatively balanced.

You need to tweak them for real-world loaded conditions, and stop making crazy output claims.

G-

[TomW]

G;

Yeah, I agree. Down the line. He should offer honest, no spin results or quit pimping them here.

We must look like a bunch of suckers?

I haven't tracked thru to any of the links but the words here leave a bad taste.

Any user with just 9 days of membership should be scrutinized very closely before simply accepting their claims. At least thats what I think.

I also passed on posting a comment with his pictures included because I find his tactics offensive and predatory. But thats me.

That is all I am saying til the coffee kicks in.

Tom AKA "Bluto"

[popeye]

  Well guys I do apologize, and I guess you really do have to be careful when you post here. Did not mean to offend anyone here or step on egos. I thought that what I was posting would be a help to someone in need.I do not wish to sale anything here. I have plenty of customers without the discussion board. You notice that I left no way of contacting me. As for the motor it was a 38 volt not a 36 ametek. And like I said the charge voltage was 24 not 12. Its cake to get 300 from a 38 that way. Just one thing before I go. Do me a favor before you get high and mighty and look on wikepedia on wind turbine blade design. This is not back yard stuff this is enginering. I will humbly digress now. You guys are now top dog again.

[TomW]

I did not realize Engineering was involved.

They must be exactly perfect for any use, then.

You are NOT the seller?

You sure seem defensive about someone else's product.

Tom

[ghurd]

I said I think the blades looks OK, and the price was OK, and they need tweaked.

There would be demand for a 4' wooden blade that did not stall with the common short-type "Ameteks".  Need to lower the design TSR and start with wider lumber.

Too much speed makes stall.  The only thing keeping it out of a very hard stall is the high coil resistance of a short 38.

Half inch tips make speed, not torque.  Comparing anything with the Air-X as an example of good is not good.

The 50V open at 18MPH means it won't reach 24V cut in until about 11MPH.

What wind speed made 300W?

There is some math in the engineering too.  Vo x Isc does not equal output W.

I could believe 300W at 24V may be possible from some Long-Versions of Ametek 38s, but 10A at 24V from a regular 38 is a bit much to swallow.

I expect you are not measuring the actual output.  Not sure anybody can get an honest 10A at 12V from a standard 38,

http://www.fieldlines.com/story/2008/5/6/0171/69661

[popeye]

Well the controversy between thin tips and wide tips remind me of when I was into making bows. There were guys that believed that certain woods would only make a good bow while others thought that certain other woods were better. And this controversy raged for mabye Im guessing a 1000 years. Well it turns out that both were right and both were wrong. When it comes to wide and narrow both have there place. If you have a gen with a low cut in speed go wide. If its a really high cut in speed go narrow. And of course there are extremes to both. Remember this guy is having trouble with wide blades not narrow ones. I have built both styles and many differant configurations. The thing that I try to target is a high TSR. And according to wind turbine engineers they claim that the higher the TSR the greater overall efficiancy you get. That is according to the info I read. And the results I get are conferming this. But here we go. The design of the entire wind turbine must be considered here. The blade is only one aspect. And it would be impossible to subscribe one size fits all. Hey, if this guy needs more speed then why not? Whats the alternative?
  As far as what wind speed do my 4 footers cut in at? They dont even get going until 12 MPH. And at that wind speed nothing in the 4 ft range is going to give you more than a trickle charge. And I think you would agree with me here. These are not low wind performers. But like I said people with motors that dont work with anything else are overjoyed to get something that makes them some amps. Even if it does take 15 MPH to really get going. The longer the blade the more torque with any design. And there is a happy medium with everything. obviously if you could get the speed out of a 10 footer that you can with a 4 footer every one would be going 10. Its a give and take. Kinda like when you are picking the size of wire to make the coils with. Thicker means more amps more current higher cut in speed. Thinner means lower cut in speed less current.
  Ghurd I think you are a really smart guy. And, I dont clain to be too smart. All my findings are just finding what other people have done and duplicating it. You like numbers and I like display. Lets stay open minded and keep refining things. Remember, iron sharpens iron.    

[mikeyny]

OK I finaly got an internet connection up here again. First of all thanks for all the feedback guys. I took popeye's advice and made up a set of blades 5 ft tapered a bit like he said. I balanced the blade by hanging a string from the ceiling and pulling it thru the center hole on the hub. It took a bit of sanding but I got the blade pretty well balanced. I also added a bit of width at the root. I saw that someone else did this to help start up in low winds. I am not sure it it helps or not but it looks kind of cool. I put a nose cone on it also. I got the nose cone from a local guy who noticed the windmill and I told him I was looking for something to use as a nosecone to make it look a little better. He came back an hour later with a nice black metal disk he found while dumpster diving. I had to cut it down to size but it looks great. The interesting part about the nose cone is that the guy is in a motorized wheelchair. I did'nt ask him if he drove in or dived in, but never the less it was a great contribution. OK on to the blades. We still have not got much wind in the past week here but the blade does get up to 12 volts in a gust. I am guessing 20 mph. Very little noise so far. I will post some more pics soon and maybee a video.

           As far as getting lots of power out of it I am not so concerned because we are still learning. Just to lite up a 12 volt bulb is great for us so far. This information and "debate"  about blades is the best way to learn. I saw Ghurds post about his little mill at the lake side and it gave me a few ideas. I may make a tower for my truck so I can get mine into a better wind area. I have it on a 6 ft tower and the wind is not so good there yet. Let the wind blow!!!!

                                                      Mike

[mikeyny]

here is one picture. I hope I got the size correct.

[mikeyny]

here is one more. The size is correct, thanks to my son Devin. The chicken coop is in the back ground. That coop sure would make a great base for the tower and, house all of the batteries and gear.

                               Mike and Devin