DIY dual Axial Flux Wind Generator

[bryan1]

Hiya Guys,
Just waiting on a few parts to arrive then I'll be making my first dual axial flux wind generator. I intend to do a log in here on the progress and the finish will be a DIY guide to making one yourself. This thread will be used as a log and as I progress along a new thread will be done in the RE Projects forum for the DIY instructions.

The one I'm making I'll be targeting for the 3-4kw range @ 24 volts with 4 metre diameter blades and one can scale down for a smaller generator.

I'm waiting on a trailer hub assembly arriving so I can get the bolt hole measurements then I'll be getting 2 350mm diameter 10mm thick steel plates laser cut. The reason for the laser cutting is if cut using an oxy torch the plate will certainly buckle slightly and this is what we don't want.

The concept of the dual axial flux generator is 2 magnet plates with the opposing magnets facing N-S so they attract then a stator is in between holding the coils which generate the voltage/current. I'll be using 50x15mm round N52 grade nickle plated Neo magnets with 12 magnets on each disk. The stator will be 9 coils with 3 coils in series to make a 3 phase output, to hold the coils a mold will be made and either high temp epoxy or fiberglass will used to make the stator.

Once the generator assembly is made the mount will be made to suit the tower I'll make and for the blades I'll use my mate's idea and show how to make 2 metre long blades using a chainsaw.

More to come....

Cheers Bryan

 

[Simple Simon]

Bryan
Thanks for the heads up on this one.

I like doing motor conversions. I'm trying something new, I'm not turning down the rotor but drilling into it.
I will be mounting the Magnets on there sides. I'm looking to make this Simple. "Like me"

Simple Simon

 

[annrkey2012]

I am considering several types of generators.

So far my plans are in the 1kw an under but I want 2.5kw+ so I'll be interested in several of your details.


What size wire, how many wraps, how you plan to make the blades...

 

[bryan1]

Hi Annrkey and Simon,
If you check out https://www.otherpower.com and have a look at the way they build their turbines, mine is on the same theory and although it won't be build letter for letter as theirs it will be close. The idea behind doing a DIY on this forum is to introduce members to the idea some of who have no idea and others that want to learn. As far as the turns ratio I will show how one can workout the turns needed for the voltage and cutin speed. I will constantly mention people look at the otherpower site and I would suggest members buy the Dan's book on the subject as that book will show more than I can in here if they are considering building one and don't have a clue on wind power.

With wind generators just remember that is only the power input part and there is a heap more items to have in place to make everything work. With solar one can just short the PV input and not worry about overcharging batteries. But with a wind generator of this nature the batteries won't like 80 amps going into them when they are nearly fully charged and a gale is blowing outside. I do feel a smart diversion project on the horizon but one has to get started.

Cheers Bryan

 

[bryan1]

Bryan
Thanks for the heads up on this one.

I like doing motor conversions. I'm trying something new, I'm not turning down the rotor but drilling into it.
I will be mounting the Magnets on there sides. I'm looking to make this Simple. "Like me"

Simple Simon

By drilling directly into the rotor and not having a non conductive bond you WILL be wasting your efforts. The only flux the copper will see is the top of the magnets so please revise your efforts and if your going to do a motor conversion do IT properly. I was on stripping the wire out of a 4kw motor when my mate said to me, with the effort and expense your going to for the return in output why bother, just build a dual axial flux and have more power than you know what to do with.

I have done a 1.5kw motor conversion and I must say without a total rewind the thing is only a 250 watt genny at best in high winds. Zubbly(RIP) was a guru on motor conversions and one can find his files on the feildlines forum.

Cheers Bryan

 

[bryan1]

Hi Guy's,
Rather than go into a long winded post about making blades using a chainsaw below is a link to the guy who originally designed this concept.

TheBackShed.com - Chainsaw cut windmill blades.

Just be aware of the dangers doing this type of thing and please ensure you know what you are doing as no-one wants to see armless RE enthusiasts.

Cheers Bryan

 

[bryan1]

Well I finally got back onto making the wind genny, I oxycut 2off 360mm diameter disks out of 8mm plate at work and today I finally got around to cleaning them and bringing them home. This weekend I'll cut a hub and axle off the 30' caravan we have on the farm which will never move again and then make the magnet disks complete. Then by carefully bringing the plates together using jacking screws I'll make some different shaped coils to see which is the best to go with. Once I get that far I'll setup my digi camera and make a few short vid's and chuck em on u-tube showing the different voltage and current outputs for each coil I wind. As I have 2 5kg spools of 14awg(1.6mm) enameled wire here I have plenty to play with and besides I get it cheap from work anyway. The 50x15 N52 round neo magnets are still in their box and when I had to separate some for my mate they were scary to try and pull apart even when they were in the north-south config with a 3/4" insulator between them.

I do have an old drawing machine here and some old cad drawing film so I am tempted to draw up the genny with each part on separate paper then by turning the drawing with the magnet disk drawn on one will be able to see where each magnet pass's the coils. This will explain in visual terms how these wind generators work and might also be worth a short vid.

Cheers Bryan

 

[shawn]

Hi brian found my way here .What you are building is just what I need and my tower was built for 4meter blades so you can call me a copycat all the way!
ok I have some heavy duty horse float hubs (new) will find someone that has a laser cutter but I need some pictures..

 

[shawn]

Bryan would A plasma cutter do ?
Do you know the price of the neos as I need to buy some there is A guy here but he said they need to be made to order lots of $$$.

 

[bryan1]

Hi Shawn,
I cut my 360mm disc's out of 8mm plate using an oxy torch and they came out nice and flat. The neo's I got came from china and were custom made, I imported 150 of them between 3 of us and I got 50 for myself. That is enough to make 2 wind gennies with 2 magnets spare incase of any mishaps. I already have an order for a wind genny using the second set and it will be a few months before I get any more magnets from China. Depending on how many orders I get for wind gennies the order could be sooner. If your contact is getting them made in China and trying to rip you off be carefull, if you let me know what size and how many you need I can get you a quote so just pm me and we can do this in private.

Regards Bryan

 

[Powerit]

How are you holding the magnets to the steel disks?

Hello Bryan... this is Frank who saw you at work today here. Are you relying just on the huge magnetic attraction of the magnets to the disk or are you actively securing them (with epoxy or something)? I seem to recall that some designs actually had cut out grid sheets that stopped the magnets trying to move sideways to or from each other. Then the disk had epoxy poured over it. Or do your magnets have a hole for a fixing screw?
Cheers ... Frank

 

[Powerit]

How are you holding the magnets to the steel disks?

Hello again. Do you have any iron (solid or laminated) in the cores of the coils? Or are they just air cored? There would be a massive increase in induced flux cutting the coils with a ferro-magnetic core material. Although this would increase drag (and maybe cogging), there would be a much higher output available. I am primarily interested in a generator driven by a slow-revving vintage engine (rated speed 600 RPM), so available wind power is not a concern. I can provide 6-HP which should give at least 2.5kW output.

 

[bryan1]

G'day Frank,
First of all Welcome to the forum mate As Neo magnets will rust at the first sign of moisture it is important to paint/seal the steel magnet disk before the magnets are installed. The general way of holding the magnets is just potting using high temp epoxy of fiberglass. What the Dan's do now is put a SS band around the diameter which not only will stop the magnets flying off it also serves as a dam for the potting material. Another way is to use roll pins to hold the magnets in place which will work a treat.

With my next shipment of magnets I'm going to get a countersunk 5mm hole put in the centre so that 5mm countersunk bolt will not only make it easier for alignment it will keep the magnet in place. Today I'll be finding out if the heavyduty hub I ordered has come in so hopefully I can get started this weekend. When I get the magnet rotors done I'll be doing a 1 coil test to find the best shape and coil count to use for a given voltage/current range. You are welcome to come up for visit and have a play.

Cheers Bryan

 

[Powerit]

Good morning Bryan. How did you go with the solid rotor/bolted on magnets idea? Do you have any test results as yet regarding coil details per output volts? I presume you will use 9 magnets on the rotor and 12 stator poles. Is that right? Cheers... Frank

 

[bryan1]

G'day Frank,
I ended up selling all those 50mm round neo's and started again on my 4kw motor conversion. anyway the next you visit you might find the place a bit empty as I finally had enough and are no longer with them.

Cheers Bryan

 

[Powerit]

Hi Bryan... now I'm a little confused. When you said "next time you visit", do you mean the place of your daily employment, or this forum? I read this that you've quit work. Is that right? Where to now?. You can email me direct at anytime, at: seifert at internode.on.net. Cheers... Frank