Printable wind turbine 55W output

[Woodworker]

Hello Forum,

I'm an aeronautical engineer and when I'm out of office I am mounting wings to generators, not to planes. Normally I don't like plastic and so I prefer to work with wood and steel. But some years ago I saw the first 3d-printer and I liked this little machine. 2 Years ago the idea was born to build a little wind turbine with a 3d printer for generating the electricity for my homemade automatic mower. I thought it will take me 2 weeks. Now, two years later it is done. The idea was to build it mostly with the 3d printer, no welding, no milling machine and no lathe. I had some setbacks! I had to modify the design during 4 prototyp series. Rigidity and cooling of the generator were only two of the items I had to spend more work on then I thought in the beginning of this project. Now it is able to produce 55W without thermal damage of the generator and two test-samples survived the european hurricanes “Christian” and “Xaver” in autumn 2013.

Here are some technical specifications:

3-blade rotor D = 0.84 m
Storm protection by stall of the rotor at wind speed > 50 Km/h
Power limitation by stall (save temperature boundary of the generator)
Generator brake by shorting the phases
Triphase neodym magnet alternator. Maximum charging power 55W (continuous output!)
3-phase collector ring
12V battery charging

I read the rules for this forum and I did not find a rule that it is forbidden to make advertisement. But I do not want to run into trouble. What I want to say is, that I made a very detailed step by step construction manual for my windturbine and I provide it together with all STL-datafiles you need to print on my website. There you also find more information, pictures and so on.

You are not meant to post links especially 'advertising' until you have made 50 posts to establish your bona fides: DamonHD

To the moderation team: If this post is not in the spirit of this forum because of advertising please take it out. I will accept and understand this.

I'll try to upload 2 pictures here to give you an idea about my printed windtubine.

If you are interested in my project you are welcome to visit my website:

No links but someone could use their favourite search engine to look for "Reprap-Windturbine"

Best regards

Andreas

[Bruce S]

Sounds interesting. At what speeds are you getting the sustained 55W @ 12Vdc at?
I understand the stall protection at 50Kph, but with blade diameter at less than 1M it gotta be screaming at a high rotation speed.
Cheers
 

[kitestrings]

Andreas,

Welcome to the board.  It looks very cool, and I have no idea how it is done.  Clearly you've persevered.

I would, however, be cautious of this type of statement(s):

Triphase neodym magnet alternator. Maximum charging power 55W (continuous output!)

At .84 m diameter, the Betz limit at 12 mph is about 60 watts. With reasonable assumptions for efficiency, this would suggest your site never drops below 18 mph (8 m/s).  Maybe you meant maximum, design or rated output, then I think this is logical.

Good luck with it,

~kitestrings

[gotwind2]

Andreas,
Very good work, it looks like you've put a lot of hard work into this. I believe 3D printing to be the future of many products.
I noticed you have a good picture gallery on your site (reprap-windturbine.com) and this interested me.

It looks like your rotors are plastic?? - you would get far better results if you had a 3mm steel backing plate on either rotor, this how it's normally done - if you're seeing 55 watts @ 12v already then you might see nearer 100 watts with steel backing discs at around 1000 rpm I suspect.

Keep up the good work 

[CraigM]

Interesting technology 3D printing / laser sintering. I noticed the material used is ABS which seems to be the most prevalent material for 3D printing. Perhaps it's because ABS has a low melting point but I'm curious if a high temp engineered plastic such as Celezole PBI or PEEK could be use with the machine you have.

I see laser sintering is also possible with high end alloys and stainless steel although the laser for this type of application is most likely much more powerful.

As Ben mentioned the magnets should be attached to a continuous steel plate to complete the magnetic circuit. Is there a steel plate behind the magnets? Can a 3D printer apply plastic over a metal structure? Or for reinforcement over a carbon fiber structure?

Great work and exciting to see how you can go from 3D Cad model to 3D object.

Craig

[SparWeb]

It looks like it would be simple to add a layer of plastic, with the hole pattern for the magnets, and in the main rotor body have a 3mm deep channel for the ring of metal.  Then assembly would consist of:  ABS rotor body - metal disk - ABS face - magnets          then bond them together as a sandwich.  Adjust other dimensions as required to fit the extra layer or inset them all within the rotor body and keep the outer dimensions the same.  As long as the stator clearance isn't changed the electrical performance will be improved either way.

At this scale, it might also be possible to purchase the metal ring you need (instead of custom cutting / laser cutting one which would cost a lot more).  For a first try prototype I would just use tin-snips and cut the circle from the casing of a discarded appliance like a toaster or microwave oven.

This is great fun.  Thanks for sharing.

[Woodworker]

Hello Forum,

thank you for your replies.

Here some answers to your quesstions:

55W continuous output: Well, may be you can understand this wrong. This means that the generator can survive 55w continuous output ( save temperature boundary. It's all plastic!!!!).....but of course, only if there is enough wind.

The rotorblades are designed that they stall at 55W and at 50Km/h (13,88m/s). At 10m/s the output ist 37W (all measured on a testvehicle).

The sound: Well, yes it is a small rotor and it makes noise, but it is not louder than a Rutland WG913 (I have one of this).

Of course, all magnets rest on a 3mm steel-ring. You can not see the rings on the pictures. They are inside sandwich-assembly.

Most parts are made out of PLA or ABS. This plastics have low melting points. Temperature is a big problem. At the moment nearly every month new materials are launched for 3D-printing and I'm pretty sure the melting points will go up. Today we cannot print PEEK or PBI but perhaps tomorrow.

Best regards

Andreas

[tanner0441]

Hi

Impressive design and manufacture, you say there could be a problem with temperature when using plastic. On the photograph of the blue unit there looks to be air allowed into the front of the hub, could you not incline the webs or profile them so there is definitely positive ventilation past the hub and out round the stator.

Brian

[Woodworker]

Hi Brian,

yes, there is an air inlet and there is an active ventilation build in.

Regards

Andreas

[Ontheronix]

I'm building this one as a science/learning project for myself. I am hesitating on the coils though: it is advised to use 0,53mm diameter for low wind sites and less turns of 0,6mm for higher wind sites. I have rather low wind (3,8m/s at 10m height) but 0,53mm wire is hard to find. Can I wind more turns of 0,6mm? Since there seems to be space left in the stator:

"For coils with 80 turns of 0.6 mm wire, the resistance between each fase should be about 2.4 ohms. For coils with 110 turns of 0.53 mm wire, the resistance should be about 4,5 ohms." I was thinking of loading it with 5 3W powerleds in series since the generator is made for 12V. These will start to take current from 10V, and will die at around 17V 1A. Is this ok? I'll shut the mill down in stormwinds so the leds don't burn.

[MagnetJuice]

If you tell us how many turns you have in that coil and if it is 0.53 or 0.6, we can help you.

Since you have low winds, you want to have as many turns as you can fit in the available space.

And don't worry about the stated resistance in the manual. You want the resistance to be as low as possible.

Ed

[Ontheronix]

It's a picture from the manual. It advises 110 turns of 0.53 mm wire, or 80 turns of 0.60mm wire. It's not clear which coil the picture shows.

[MagnetJuice]

You said .53mm wire is hard to find. You have other options. Find out what other wire diameters are available to you.

You can wire 2 smaller diameters in parallel (we call that 2-in-hand) to obtain your desired diameter. For example:

2 wires of .36 mm diameter in parallel equals .51 mm
3 wires of .32 mm diameter in parallel equals .55 mm
2 wires of .4 mm diameter in parallel equals .57 mm

I think you should try to wind your coils with wire of about .57mm to keep the resistance low and get enough turns in the coil. Like I said before, get the available coil space completely full.

Also, I have my doubts as to whether this alternator can reach 12 volts with the low winds you have. But it should be fine to do the job that you have in mind.  If you can only reach 9 volts, you can have 4 of those 3 Watt LED's in series-parallel.

Ed