Taking a stab at wind

[Madscientist267]

I want to try my hand at wind, with a not very serious design to start off.

What my intentions are, is to build a small mill that will sit about 10 feet off the ground out in the open space next to my house, somewhere in the neighborhood of a 4 foot rotor... ?

It's not ideal for wind conditions, or to do any serious charging with, but I just want to get my hands dirty in this so I understand more of the principles than anything else.

I do get fairly steady wind when it is here, sometimes in the 20 MPH range, so I figure, why not.

Looking to build a 12V nominal system, with the motor as is.

Here's my motor:

http://www.monsterscooterparts.com/24v250wmotor.html

I will probably even gear it up, I have the wheel sprocket and chain from the scooter it came from.

The blades will be made from 4 inch thinwall sewer pipe.

If I get even 50W out of this thing, I will be happy. To start.

With that being said, where do I begin?

I realize that I probably haven't given all the specs you might need to give me a solid starting point, but I've done some reading on this side of the board, and understand the very minimal basics to get me going.

Unfortunately, this only takes me about as far as knowing about what it's going to look like on the tower.

Steve

[Rover]

Hi Mad,

Not so sure about the motor, not many specs on the web site. 24V motors typically not very good for power generation. I think you are going to have trouble trying to get 50W from it.

[Rover]

Ok, I just saw the spec page , 2600-2850 rpm. Best case scenario 2600/24v ~ 110 rpm/volt.

figure cut in at 12V 12*110 = 1320 RPM.

Unreasonably  high rpm, if you do manage to make it there, your neighbors may string you up for the noise.

And the power at that point will be minimal.

[DanB]

Interesting website - they have some interesting stuff and pretty low prices.

At any rate, the motor you mentioned is rated for 24V at something like 2700 rpm.  Assuming its a permanent magnet motor, I would expect 12VDC at about half that rpm (1300 rpm)... which is really way too fast.  You would need to gear it up for sure.

For a simple project like this, I'd consider playing with a treadmill motor.. or an ametek tape drive motor... or - off that same website, if 12 Volts is the goal, I might shoot for the 48Volt motors, they will likely cut in sooner although they do not give rpm specs for those motors.

I worry that the chain drive on such a small wind turbine is really going to hurt you unless you run a very slow rotor that's got lots of torque... in which case you need to gear things up even more so at the end of the day you might lose either way.

[defed]

i'd just make an axial.  i did.  4' piggot on an 18' pole.  like you, it is a test model before i venture into a bigger one.  want to do a Chris Olson 12G next.

i'm pretty happy w/ how the 4' is working.  it has produced 1kwh + in a day a cpl times (between 6 and 10 hrs of generating) and have had a peak output of almost 500w @ 16 amp.  the only problem i have w/ it is that it is a hard starter.  i used a car rotor and bearings.  the bearing is a double stack ball type (not sure the exact name).  in summer, the seal drag is enough to make it need a good 30 second gust of 15mph+ to get it kick started, but once running, it would continue to generate down to about 7mph.  in winter, not only is there seal drag, but the grease must be getting too thick.  it will only hit cut in in EXTREME winds.  it will still turn lazily, even in light winds, which confuses me that if it turns at all in almost no wind, why can't it break free?  but due to the bearings, i can't repack them w/ lighter grease.

it was pretty easy to make.  hardest parts are carving the blades and casting the stator...but all in all, not bad.  good learning experience.

[Rover]

If you are bent on repurposing a motor due to the simplicity, I agree with DanB. In the same vein have a look around the board for GE ECM motors, they are more in line with your desired output wattage (50-100W). They are a good place to start and get you through most aspects of a larger build (rectification, wiring type (star , delta) , etc).

 Don't get your hopes too high with a 10ft height, very turbulent air.  I really don't recommend it just for the danger aspect.

 

[tanner0441]

Hi

I have one of those motors and they generate well...... If you can turn them fast enough. Like in the 1000s RPM. Look on the motor plate and see what speed it turns at at the design voltage and that is your starting point. The motor I have is 5000 RPM at 24V so to charge a 12V battery your looking at nearly 3000RPM.

The advice to build something is the way to go, plus the height you want to mount it the air will be very turbulent.

Brian.

[Madscientist267]

Wow, the replies pile up quick on this side...

Already gaining some good insight. Keep 'em coming...

defed -

You said 4' piggot on an 18' pole... is that with PVC blades?

And what length would each individual blade be... 20-22 inches?

Another concern is the height of the pole. I grabbed 10 ft out of thin air (no pun haha) due to the idea that I have no idea how the town is going to react to anything of real size...

Steve

[defed]

i carved the blades from regular old 2x6 hem/fir/spruce.  they are 24" each.  was pretty easy once you get going.  i used a hand saw, chisel, and spoke shave.

10' will be bad, but it WILL work.  mine was around 12' when i started (mounted in on my tilt over purple martin house pole), then i pushed it to 18'.  wanted 20' min but i don't think the base pole will handle any more.  granted, it would be alot better at 50', but like you, i did it low as to not get into trouble w/ the town.  they haven't bothered me about it.

[Madscientist267]

Something else I just thought about.. I actually have two of these motors.

What if I were to take them and put them at opposite ends of the rotor and drive them both... wired in series.

Any ideas as to what that would come up with?

This particular motor is rated 2600RPM @ 24V, so I figure (as mentioned) ~1300 to be in the 12V range, but in series this would translate to 650?

Would a 4 footer be able to supply enough torque to be able to hit that at the motors?

Please forgive me, I'm not discounting everything I've read. This is all good information, I am sure.

I'm just looking into all the possibilities.

Steve

[ghurd]

I think it would be less frustrating to start with something, uh, easier to make work.
Lots of better choices than scooter motors.

10' is too low in town, if there are many kids running around.  I'd want to go at least 12' to get a bit more out of reach.
Nobody messed with any of mine but they were where I could see them out the window, and I brought them in the house at night until other people's interest wore off.
G-

[Madscientist267]

If I were to go axial, I'd have to buy one. I don't really have the tools to build all of this stuff.

I can carve the blades, that's one thing, but making the alternator and all that, I just don't have the resources really to do it.

Someone sell a pre-built axial that would work with 4ft pvc blades?

Steve

[Rover]

OK, then look for a treadmill motor, or ECM. There is a chap on Ebay right now selling GE ECM's 1HPs for 133$ or best offer (new ECMs) he has 10.  I know because I made him an offer for 1.

 They do work, they are a little more work, but less than an axial, and they will work better than the motors you have.

 Back to the tower height, please try to get it to at least 15'. As Ghurd and I have mentioned ... besides the turbulence, it is dangerous.

 15' is just for safety, it is still not good as far as turbulence.

[97fishmt]

 I just bought a permanent magnet ac servo motor on ebay 2 day's ago
for $19.99.  It should cut in around 190 rpm, for 14 volts, a little high for me but, for $20 it's rated at 10 amps.  I know from experience it will do at least
4 times that.  I'll try and pass on the savings to a neighbor.

 I wouldn't try to gear anything in the smaller rotor category, there are options out there.  I used to make geared machines 15 years ago,  5:1 worked OK for some of my stuff,  (brushed dc motors) 2 or 3:1 would work better, it depends on the motor you're starting with, but start up is a problem with small machines.  You might get good results with a larger machine with gearing.

 So keep reading and keep the dream alive,  you'll be hooked once you get something whirling around.

Mike

[fabricator]

If you end up going the geared route you are gonna want some pure torque blades, these blades fit that bill.
http://royalwindandsolar.com/index.php?page=shop.product_details&flypage=vmj_genx_img1.tpl&product_id=21&category_id=8&option=com_virtuemart&Itemid=65

[defed]

If you end up going the geared route you are gonna want some pure torque blades, these blades fit that bill.
http://royalwindandsolar.com/index.php?page=shop.product_details&flypage=vmj_genx_img1.tpl&product_id=21&category_id=8&option=com_virtuemart&Itemid=65

doesn't look like they make them for a 4' diameter.  besides, that's alot of $ for a 4' machine!  maybe a water pumper type would work?

[fabricator]

I'm pretty sure he'll make 4' blades, the price all depends on whether you have facilities and abilities to carve your own blades and they'ed be one hell of a lot more efficient than pvc blades, but hell, for a first try at getting your hands dirty, just do it!

[ChrisOlson]

I worry that the chain drive on such a small wind turbine is really going to hurt you unless you run a very slow rotor that's got lots of torque... in which case you need to gear things up even more so at the end of the day you might lose either way.

For horizontal axis turbines I think gearing only makes sense when you get to a certain size machine.  Up to 10 feet you can build a pretty efficient generator without spending an arm and leg and the rotor runs fast enough, and has a wide enough operating rpm range so gearing doesn't really work.

Once you get to the point where you have to start adding poles to the generator to get all the copper to fit in the stator, and use bigger more expensive magnets along with a large rotor that will make more noise running at high speeds, then gearing starts to pencil out.  For a little 4 footer that can run over 1,000 rpm at a pretty mild 6 TSR I think it's better to just use a direct drive generator of some sort that matches the cut-in speed you wish to get from the rotor.
--
Chris

[DanB]

For horizontal axis turbines I think gearing only makes sense when you get to a certain size machine.  Up to 10 feet you can build a pretty efficient generator without spending an arm and leg and the rotor runs fast enough, and has a wide enough operating rpm range so gearing doesn't really work.

I think at this point gear, or chain (or whatever means of gearing things up) can make lots of sense.  Especially if magnets get lots more epxensive.  But...  there are pretty nice direct drive wind turbines on the market up to at least 1MW rated output.  A gear box is an 'extra component' with more moving parts and it involves a whole new set of pros and cons.

[ChrisOlson]

But...  there are pretty nice direct drive wind turbines on the market up to at least 1MW rated output

True.  And there are also pretty nice turbines on the market, classified in the Small Wind category, that are geared:
http://www.windturbine.net/documents/Brochure%2031-20.pdf

--
Chris

[Rover]

Ok, think we might have veered off course a bit ,  the original poster , Madscientist267 ,  is looking for a way to get into this cheaply without a lot of fabrication work .  I have no doubt that gearing works, and I've liked your posts Chris ( fact they have inspired me for other avenues).

Neeed to help Madscientist267  here. Who has stated he does not want to build an Axial for the effort level.

I guess we are all trying to help him find a direct drive, low start up cost alternative to his motors. Of which there are a few.

[zvizdic]

Here's my first attempt at wind 90 vdc motor 1 / 3 hpmax200W.

[97fishmt]

Excellent!

You got what it takes.

Keep up the good work and it will pay off.

[Madscientist267]

Yeah, zvizdic's machine is more like what I'm looking to do...

I have some significant limitations in my abilities to get done what I wish to accomplish, so the simpler, the better.

This is mostly so I can understand all of the basics involved.

I have been poking around to find out more about the various terms I see on here regularly, ie cut-in, TSR, lift vs drag, etc... Still not entirely certain about some of it.

But when it comes to applying what I have been able to figure out to an actual machine, I don't know how it all translates into the actual physical device. Particularly the blades. They're still very much an enigma to me.

Much of the other aspects I have a fair grasp on at least the principles... and some of that of course translates over from solar (ie dump controller etc).

As predicted, you all are very much a help in this, and for that I definitely thank you.

So let's talk more about your 90V PVC system, zvizdic. I think you've hit it on the head.

Steve

[SparWeb]

I got my start just taking stepper motors out of printers.  I cut some PVC blades, jammed them on the stepper shaft, and instant wind turbine.

I still use one of those as my anemometer.  Tidied up the wiring and made a durable mount for it and so on but that's details that go with any wind turbine.

Somewhere in my old files I should have a picture of it, but I never remember how to find them (not without deleting this typing anyway).

You can only get a few watts from a stepper motor, but if it's only for the sake of experimenting, it's easy.

The PMDC mill is another great way to start - it's just less likely that you can find one of those motors for free like you can with stepper motors.

[Madscientist267]

Best to go with a larger 3 phase version I take it, right?

And elaborate on 'few'... 5, 10, 50?


What about 5.25" floppy drive motors? I have one here...



It's (edit with correction) 4 phase... doesn't appear to be really much different from what I see you guys do with axials... not sure how it's wired; got the magnet off, but now I'm having problems determining which connections go to which coils so I can scribble me up a diagram:



More editing - I took the tracing homework out of the equation for anybody who has any input on this... Looks like 4 phase "boxed delta" type thing to me. Not sure of the technical term for it...



Spinning at just a few RPM, it puts out a couple hundred mA directly into the meter (across the right terminals)...

--- Even More Editing ---

I believe I've traced out the diagram, but if someone would, double check me and make sure it works... Not 100% positive about the position of the coil connections for each coil, and cant get under the coil shield to find out unless I drill out the rivets... was going to be a last resort, but I don't think I need to.



What I believe to be the correct coil connections...


and:



The schematic based on this information...

and, last but not least, the resistance measurements of each node to each other node:


(From - To =  Resistance)

Red -
   Orn = 20.7R
   Yel = 15.5R
   Grn = 15.5R

Orn -
   Red = 20.7R
   Yel = 15.5R
   Grn = 15.5R

Yel -
   Red = 15.5R
   Orn = 15.5R
   Grn = 20.7R

Grn -
   Red = 15.5R
   Yel = 20.7R
   Orn = 15.5R


Steve

[zvizdic]

Yeah, zvizdic's machine is more like what I'm looking to do...

So let's talk more about your 90V PVC system, zvizdic. I think you've hit it on the head.

Steve

If you are near Toronto Canada I would have given you spare blades. They are made of 8" PVC tube 32" long.
 I left them unloaded turning around 800 rpm no problem.

[ghurd]

For my steppers out of printers, a 'few' was less than 2W at 12V.

For stuff out of computer related stuff, a DLT tape drive motor (3-ph) can make some pretty decent low voltage watts, if someone had the desire to make a boost converter or find matching transformers.
3VAC open, rectified 3VDC open, 3A DC Isc.
Not sure where all mine went, and too cold to dang look very long, so I will steal the below pic.
Bigger than it looks,
http://www.otherpower.com/images/scimages/3666/Tape_drive_motor.jpg

If the coils in your floppy drive are like an axial, then the drag from eddy currents in the metal mounting plate will eat up all the potential power.
http://www.otherpower.com/images/scimages/2050/VCRmotrs.jpg

Edit-  Fould a pic showing some details,
http://i701.photobucket.com/albums/ww20/ghurd1/Stray%20Pics/PICT0871.jpg

G-

[Rover]

Hmmm, I have a cpl of Compac DLT's sitting in a trash can in the server room (been there for at least 5 years no one is allowed in the server room. no one can eat there, trash builds up very slowly) ... I might have to take em home

Ok tangent over, please excuse the non topical post

[ghurd]

If someone had great patience (VERY bored), could rewind one with more turns of smaller wire (maybe from a very small {13"?} color monitor).
I'd suggest throwing some kind of magnet keeper iron in the magnet drum while doing it, because the magnet can lose a lot of power if the core is removed very long.

Never throw away an old commercial server HD without looking at the magnets.
G-

[scoraigwind]

What about this?
http://www.windbluepower.com/Permanent_Magnet_Alternator_Wind_Blue_Low_Wind_p/dc-540.htm

[Madscientist267]

scoraigwind -

Very nice, but unfortunately way outside the price range I can do at the moment.

G -

Found out after all that, that the cut in is a bit too low also on the floppy drive. May be able to make a really small one from it. Thinking 1 foot blades, attached closely to the edge of the magnet disk, and spinning it's nads off. Might get a couple handfuls worth of wattage out of it, but otherwise I am back to square one.

I am actually considering a little more power than what is being mentioned here. In the process of doing all of this, I'd like to effectively be able to augment the PV array already 'in place'...

Steve

[Slingshot]

I often refer folks to this site when they express interest in building a simple wind gen with treadmill motor and PVC blades:

http://www.velacreations.com/chispito.html

It's not a bad little tutorial, and it doesn't get much cheaper than this.  I've seen these motors locally for $20 or less.