www.smallwind.co.uk

Before we start.

A few quick notes before we get started.

I'm building my wind turbine out of materials that I have available, or can obtain for free. The main construction will be mostly of wood or MDF. There are no doubt much better materials I could use, but this is just a hobby, so I'm using what I have available.

That said there will be some items that will have to be bought. For me, these are:

Bearings
Neodymium magnets, AKA: Neo, NIB, NdFeB or rare earth
Enamelled copper winding wire.
Stainless steel rod, nuts & bolts etc...






I am not an expert in building wind turbines so some of my reasoning behind the decisions I make during the build may be way off, but that's all part of learning. The design will most likely change as we go along. Although I have a CAD model draughted. It's just to get some visual ideas of how the parts will fit together. Don't be surprised if we get "so far", then go back a few steps to work around an unforseen problem. Hopefully that won't happen, but it's possible.

Any electricity produced by the wind turbine will be stored in 12 Volt batteries. An inverter will be connected to the battery bank to provide 240V @ 50Hz. My aim is to power all the lighting in my workshop. I have tested a 240V compact flourecent lightbulb using a very cheap inverter and a car battery. Hey presto, we have light. So the idea seems good. Let's see if we can make it work.....

Making the Parts

Here the parts will be listed in the order that I'm making them. Click on one of the thumbnail images below to view a description about each part. The list will grow as I build each new component of the wind turbine and new CAD files will appear in the Download section for each component listed here.

Design Chage: Yes. I've changed the design already. The original plan was was to connect the two magnet rotors together using 6mm bolts around the outer edges and to hold the stator, (coil disk), in place through an opening in the rear magnet rotor. I've now deceided it would be better to join the two magnet rotors through the inner 8mm bolt holes and attach the stator via an outer bracket. This means that what was the front magnet rotor is now the rear magnet rotor. The part and file below, (The Purple one), remain the same except for the name change.



First up are the blades. Click the thumbnail (left), to view a description and some photo's of making the blades for the wind turbine.


The rear magnet rotor. Click the image for more details.




This part will be the front bearing ring. Click the image for more details.




Making the Stator. Click the image for a bit of info on making the sator.








The Front Magnet Rotor.








Miscellaneous Parts.

Here you can download the CAD files for building the wind turbine.

The files are in .IGES, also some DFX files are included.

Part Name: File Size Files Contained

Turbine Blade 205K Zip file 5 files
Rear Magnet rotor 399K Zip file 2 files
Front Bearing Ring 54K Zip file 2 files
Coil Winding Form 89.6K Zip file 2 files
Stator Bracket 15K Zip file 2 files
Stator mold 4.6K Zip file 1 file
Front Magnet Rotor 787K Zip file

Video Downloads.



I captured some footage of the wind turbine with the test set of blades on a windier day. Plaese excuse the wobbly test rig and the nasty looking tail.

3Mb WMV

This is a short video clip of the set of test blades I made for the wind turbine, before going ahead with the rest of the project. It wasn't a very windy day and the motion doesn't capture well on video. The file is a 1.5Mb WMV
Here is a small video of the CNC router in action, cutting one of the wind turbine blades.

7.5Mb WMV

Initial Test Results.

I finally found time to get all the bits and pieces together, and get the wind turbine up for a test run. For the first few days there was little to no wind. Typical..... After about a three day wait, I was rewarded with winds of around 9 mph. That was enough to get the wind turbine up to cut-in speed. I don't have any kind of tacho on the machine, so I'm not sure at what RPM, cut-in is achieved. I'd guess about 180 RPM.

So......How much power was it making?

Hmmmm...........Not a lot. I saw around 5 Watts on the first day that was windy enough to reach cut-in. I re-wired the stator to reach cut-in at a lower RPM, and although it started charging the battery sooner, there seemed to be more drag, preventing the wind turbine from reaching higher RPM's.

I knew the all wooden alternator was not going to produce much but I was expecting more than 5 Watts. It seems that one inefficiency in the design has a cascading effect on everything else. Firstly. The magnet rotors are made from wood. This is bad because it does not complete the magnetic flux path. A steel rotor would be a much much better choice. The wooden rotor makes the magnets inefficient, and so you need more turns on the coils to reach the required cut-in voltage. More turns means more electrical resistance in the coils and to get more turns you must use thinner wire, which increases the resistance even more. So one inefficiency leads to increasing losses all over the place.

I've deceided to leave this turbine as it is, rather than try to improve on it. So, it's lessons learned, and the Mk2 wind turbine is under way with bigger magnets, steel rotors and thicker wire. Maybe some bigger blades too. So Stay tuned......... The building of the Mk2 will be comming soon.

The Mk1 has been in the air for about 2 weeks. The highest output I've seen is around 20 Watts. It may have gone higher while I wasn't looking, but I think it's fair to say that the average output from this turbine is very poor and of little use. At least I have a very cool weather vane for my efforts. ;-) It's been fun and I've learnt some valuable lessons to help with the Mk2.....

Building of the Mk2 wind turbine has started.....Check it out here