need help

[raine]

been working on a lofty goal to build a outer ring turbine generator.  been having a bit of difficulty and looking for a bit of guidance.

Project:  27" diameter shell (outer ring) with 27, 22 g., 250 wind coil with a oval 1/2" x 1" center and each a little less than 1/2" think.  they fit nicely around the outer edge of my casing.  with a steel back plating 1.25" wide

http://www.dyocore.com/turbine/coils_27.jpg

On the inner turbine, I have 36 magnets, 1/2" x 1" x 1/2". with a steel wire (16 g) backing I ran around the rim about 6 times.

All my coils are placed in the same wiring config - positive lead to the left around the outer ring.  I have configured a 3- phase STAR.

there is about a 1/4" space between the magnets and the coils when assembled

A1+ to A2-, A2+ to A3-, etc...

When i try to test any one phase i get fluctuating readings.  from neg to pos - just a few v each phase.

When i connect all three phases I get only about 5 v total but nothing steady...  have a small led light that flickers as i turn the center wheel - at about 100 rpm.

I expected quite a bit more power and think my wiring is wrong or my coils are wrong.  My goal with just a light spin was about 20 v.  Am i off base that much?

here's a video of my first test but as you can see, very poor results.  the video is over 40mb.  

http://www.dyocore.com/turbine/benchtest01_8-4-08.MP4

thanks for your help!

[dnix71]

Your wire coils have no ferrite cores. That would increase inductance. What type of magnets are you using? The air gap seems large and doesn't look 'adjustable."

[vawtman]

Yah Dnix i'm sorta lost myself but could'nt get the video goin.

 Wondering whats driving the device.

[dnix71]

I converted the original mp4 file (43 MB) into a 4.2 MB flv.

http://www.savefile.com/files/1725690

for those on dialup. I couldn't get his mp4 file to play in Quicktime, either and I'm using dsl.

www.videolan.org has a media player called VLC that will play a flash video offline if you need to. My browser won't play it without it being on a web site first (like youtube).

[raine]

36 x 1/2" x 1/2" x 1" long Block, Grade N42, Neodymium Rare Earth Mag.

there is about a 1/4" gap between the mags and the coils.  

No, I do not have a core in the center of the mags, only the steel backplate.  what is meant by core?

thanks - d

[raine]

device is currently be manually turned but will eventually be wind driven with a 6 blade center.

http://www.dyocore.com/turbine/spins_great.jpg

[dnix71]

A ferrite core will give a higher inductance than air.

http://www.bcae1.com/inductor.htm

That makes the arrangement more efficient.

[dnix71]

You don't appear to be stacking the voltage, either, by connecting every third coil to each other in series. That would give you 3 phased output which could be put through a full wave bridge to rectify it.

[raine]

on that link it refers to an "air core" being the most efficient for hight power.  my goal is about 2000 watts or greater.  Did i miss-understand?

[raine]

Yes, I think i have setup the STAR config correctly.  there are 3-phases,  27 coils and 9 sets of 3 coils.  every 3rd coil is connected but quite possibly connected wrong.  the link is pretty much what i'm utilizing:

http://www.dyocore.com/turbine/star_wire.jpg

[methanolcat]

    From what I see it looks like your coils would be better turned 90 degrees so that your magnets are passing the long side of the coils rather than the short side.

   Matt

[dnix71]

That setup has a common neutral, so it's not really 3 phase. I was thinking 3 separate windings each fed to a full wave bridge to convert to dc.

2000 watts output with phone line (22 gauge) as windings won't work. 2 kw of power out would require more than 2 kw in. You can't pedal a bicycle that hard standing up out of the seat. 1 horsepower is about 746 watts.

At nominal line voltage, 2 kw is 16.7 amps.

[raine]

do you have a reference link or diagram?

[raine]

I will try this tomorrow.  I was going to run a new set of coils - 18 g.  and re-setup the outer ring.  I will turn the coils 90 degrees.  thank you!  any comment on if I need a center filler for the coils?  I was going to use standard fiberglass resin when all is set and fished.

[dnix71]

The best filler is iron filings/powder mixed with epoxy. Air doesn't store inductance like iron does.

I don't know about turning the coils. The picture is an example of a brushless motor. The grey in front of the white plastic winding holders is a stack of flat steel sheets that help reduce the air gap by following the curve of the rotor magnets as they turn. In this case you are running it "backwards" by spinning the rotor to induce a current in the winding. The flat stacks focus the field and reduce eddys in the coil assembly. Filing or powder can do the same thing.

The reason for three separate windings is in case one sets shorts or otherwise fails.

If they are isolated with diode bridges, then you will still get the output from the remaining good ones, and with the alternating windings the arrangement will still be somewhat balanced.

[raine]

I think i get it.  the objective is to close the gap with a conductive solid between the magnets and the coils.  I'll look into how to do this.  does it half to be separate fillers between each coil or a single filler along all coils?  Whats the end gap I should be hoping for?  less than 1/8"?

[Flux]

"When i try to test any one phase i get fluctuating readings.  from neg to pos - just a few v each phase."

Sounds as though you are trying to measure volts on the dc range.

Flux

[tecker]

With 1/4 air gap and coils around 1/2 to 5/8 thick  your betweem 3/4 to 7/8 to the steel backing. the coil legs  are very short turned that way a few volts at 50 to100 rpm is about right .

[tecker]

You can't just fill the center with fillings or steel the core has to be aligned with the magnet moment . Draw out the geometry the stator is using and look closly at the magnet alignment .You see very little with your meter you need a scope to view the charge and release.

[wooferhound]

If you put cores into the coils, the magnets will want to attract to the cores, and on a machine with that large of a diameter will make startup very difficult. It's best not to use cores in the coils of a wind generator.

[wooferhound]

I can't get any of the videos to work ?

[wooferhound]

I mentioned this above, but it's important enough to mention again. Putting Ferrous metals into the coils will make the generator more efficient, but the magnets attracted to these cores will make it incredibly difficult to get started and you may need a kicker motor to bump the props into motion whenever there is enough wind. Air cores are best for wind generators.

[wooferhound]

ALSO

you mention a "conductive solid", that should read as "magnetic solid" because if you tried to use aluminum or brass it would cause drag from eddy currents without any benefit to output power.

[electrondady1]

your video runs on my computer using quick time

it's impossible to tell what your magnet spacing is.

the space between your magnets should be about the same as the width of your mags.

what is the dia. of the wheel you have the mags  mounted to .

can you detect any magnetic flux on the back side of the rim using a steel paper clip?

if so you will need to add more steel in there .

i would recommend you google search the board for "electric ed"

look for diagrams showing the relationship between coils and mags.

the center hole of your coils should be the same shape and size as your magnet.

the width of the legs of your coils should be such that when the outside of one leg is over a magnet , the inside of the other leg of the coil is over the adjacent magnet.

don't put any sort of iron filler inside the coils.  

[raine]

all this is very helpful!  

1.  yes i was getting magnetic attraction from the back side of the rim, I will have to add more steel.  
   
2.  The magnets are the size of the center hole of the coil and I will NOT fill the center for now to prevent clogging.
   
3.  Yes i was testing DC voltage.  I will go down and pick up a strobe today.  
   
4.  I have noticed some alignment problems and i will re-set the coils today and be more precise in re-assembly.
   
5.  Once i have a new build I will do another video to post and try a different format.
   
6.  I will check out information about "electric ed"
   
   

Thank you everyone!

[raine]

I would like the end build to spin at very low wind speeds.  I will avoid a core for now.  was thinking about a small solar motor that would keep the turbine spinning during sun hours but might not be enough to break clogging.  I'll have to do a new build and some tests.

[tecker]

I looked at the video and there's a place right after he pans away from the meter towards the end . The gaps looks very large more than 1/2 " . Use filings, black sand etc.  on paper to see how much flux goes forward and how much turns . These lines can be compared to rubber bands they have to stretch and deform the shape of the wave guide around the copper going from a even round to a compressed ellipse before returning and passing current. If nothing holds the bands from the other side proximity to the copper the copper is not effected . Also the large hole makes a divot in the peak waveform :As the coil conducts slightly and back emf returns the peak before center conduction. . Add a steel ring for magnet backing that will also close the gap more mags more coils and turn the coils . The resistance is very high now so some creative connection are definitely in order to get good power. . The reluctance idea is cool but you can see how little the flux is to the steel ring to be able to affect the wheel.

Here's videolan to run the mp4

http://www.videolan.org/

[Flux]

You can't measure the ac output of the coils with a dc meter. That is why it is going negative. You will need to use the ac range or connect your coils to a 3 phase bridge.

Flux

[dnix71]

VLC will play the flv I made, too. Download it to play offline. It's 1/10 the size for people still on dialup.

[dnix71]

Here is a screen cap selection showing the air gap. The magnets are round and become invisible when the hub turns.

[vawtman]

Hmmm going back to the basics.When you assembled the rim did you test the polarity of the mags or just put them on?Are the mags positioned has designed also?Just ckecking.

 Mark

[terry5732]

Even without cores, it looks like you already have cogging

[raine]

27 coils with a 1/2" x 3/4" oval center set in resin. I'm going to test this tomorrow.  my question is - do the coils have to be touching?  As you can see I have about 1 1/2" space between coils.  will this cause a problem?

I used a Star configuration with 21 g wiring - 150 turns.

I'll post a final test tomorrow sometime.