diyWindPower's logo

Wind turbine vertical

View of 600w axial fluw wind turbine on 8,5m scissor type tower. Can be raised and lowered using very little effort. Ideal for both urban and rural installations

Technical

This page details how to build a 3-phase axial flux wind turbine. This design is closely related to designs you can reference on the net. The Technical Drawings at the bottom of this page supports those designs, but are all in metric sizes to make things easier in the South African market

I successfully used this alternator, detailed in the text and technical drawings below with anything between 1,5 - 2,5m diameter blades

For further reference, refer to my "Gallery" page to get a better idea of what the different components look like in the real world

Also, if you look at the following link "Rotor assembly" you will get an idea of what a side view of the assembled alternator looks like and may help to put things into perspective when reading through the balance of these instructions. Refer also to the "Exploded view" which also contains notes on how to assemble the alternator

I suggest having all the flat plate components laser cut. Although it can be done using other means. It is quick and easy and because of the tight tolerances, will result in a vibration free wind turbine

For me, the most challenging part is the stator. I suggest buying one unless you are fairly good with resin and glass fibre. I can supply you with a good quality finished sator wound to either 12, 24 or 48v. Making it yourself would require that you build a stator mould and coil winder, which if you are only building one, are costs you could use to offset the cost of a finished one

That said, let's get onto the detailed instructions:

Check out the "Products" page for prices on the diffent components if you choose the buy rather than make yourself

 

1. Axle Spindle and Hub

 

You need to source a standard trailer axle spindle and hub. As you would find on a standard 750kg trailer. A four stud with 100mm centres. I choose to have it lathe cut to 13mm. This provides an accurate surface onto which the rear rotor seats. If you speak to your local trailer spares supplier, you should be able to source just one end. These stubs are normally used on rubber suspension models so should be available as a standard replacement part

 

2. Rotors

 

Front and rear rotors have been designed to accept 50x20x8mm neodymium magnets. I found this size to be good value for money and they are good for 1kw (tested). You'll need 24 magnets to complete to two rotors. Be sure to buy plated ones as they would rust if not plated. I would strongly advise you to electroplate the rotor disks and magnet plates. Paint them afterwards if you want the looks

The only work required to assemble them if laser cut, is to countersink 12 holes on each magnet plate (inner surface), so that the 12 - M6 x 20mm Stainless Steel Countersink Allen Screw heads on each rotor are flush with the inner surface so as to prevent contact with the stator. Bolt the two "Magnet plate" to the two rotor disks using M6 bolts and tighten. Drop the magnets into the rotors by sliding them in lengthways. They will snap into position, so don't be alarmed. Use safety glasses when doing this as they are quite brittle and although I have never had one break, one wouldn't want to take the chance of an eye injury

Warning - These magnets are very strong. Individually, if allowed to snap together, they would surley result in some pain. Once assembled, if the whole rotor were to come together with any part of your body between them, injury would result. When working with the magnets or rotors, work on a surface free of any iron fillings. When done drive a nail into an overhead beam and store the rotor disks out of harms way far enough appart from one another

 

3. Stator

 

The best option here is to buy one. I have a proffesional mold and can supply your voltage choice of stator. If you insist on making one. I can provide you with detailed instructions. You will require about R500 copper, R400 resin and glass matting and add to that the cost of the mold itself. From experience you would come close to the same cost of buying one. Refer to my "Products" page for cost of a complete stator

If you make it yourself, be sure to check on the position on the mounting holes so that you stator fits the mounting holes on the "Stator bracket"

 

4. Blades

 

If you are a capable woodworker, then tackle the building of the blades yourself. There are many designs on the net. If you choose to buy them, see "Products" page

 

5. Turbine Chassis & Tail Boom

 

Drawings to be added soon

See "Gallery for an idea of what is required. You would need to know how to weld to complete this section.

The pipe dimensions required are all deatiled here "Pipe cutting list". I suggest using sched 40 pipe for it's strength and tighter tolerances, although thicker walled conveyance pipe can be successfully used. Other parts required for chassis and tail boom can be found in "Flat plate cutting list"

I strongly suugest hot dip galvanising the complete chassis and tail boom to ensure years of rust free operation. You need to tape up the axle spindle with a good couple layers of masking tape to ensure the bearing surfaces and thread don't get filled with galvanising

See "Gallery" for completed chassis and tail boom

 

6. Assembly

 

See "Rotor Assembly"

Start by attaching the complete rear rotor to the hub with 4 - M12 x 70mm HT 1,5mm thread pitch bolts. Don't use any washers at the bolt head as the length of the 70mm bolts is just enough. Tighten the 4 - M12 bolts down.

Place assembled hub and rear rotor onto the axle spindle and tighten axle bolt and fixing pin into position. The bolt should only be tight enough to ensure there is no play on the bearings and allow free rotation of hub. Fit bearing cover cap

Place 6mm worth of washers and a single 10mm thick (standard) HT nut onto the the threaded end and tighten down.

Place stator loosely in position

The next step requires some caution. The front rotor needs to be lowered into position under control. Failure to do this will result in the two rotors pulling together with extreme force

This can be done safely by cutting a 1m M12 threaded bar into four, grining one end of each so as create a conical point, then thread each into the four threaded holes in the front rotor plate so that about 100mm sticks through. By undoing each of the bolt slowy in turn, you can slower and in a controlled manner lower the front rotor plate into position. Completely remove the four pieces of threaded bar when you feel that the front rotor has come up against the nuts you already installed

Ensure there is at least 1mm space between the two rotor plates and the stator. If not, remove the front rotor plate and insert extra washers. You want there to be just enough play to allow the rotors to pass freely over the stator

Tighten the front rotor plate into position with four M12 HT nuts

This leaves just enough thread to mount the 6mm blade hub

 

Technical drawings:

Rear rotor

Front rotor

Magnet plate

Stator bracket

Flat plate components

Pipe cutting list

Rotor assembly

Rotor exploded view