Wednesday, 29 October 2008

Wednesday 29th Lab session

The rectifier mounting holes were drilled + bolts cut to size.

Steel parts for stand and tail were all cut all ready for welding next week.

Tuesday, 21 October 2008

Wednesday 15th Lab session

Last Wednesday we had our first EA1 lab session of the year. A good start was made on the next stage of the turbine build.

The Stand

A stand is really useful for balancing the blades. The stand will also be able to be used for a display which we hope to have in engineering so that everyone can see the turbine. In the lab session we managed to get hold of all the steel that would be needed for the stand thanks again to engineering. Picture shows Suneil standing proud! and how the stand will look once we have it all welded. Next step is to prepare for welding and then weld.

Rectifier box
The rectifier box was marked out ready for drilling.


A start on the tail was made. Unfortunately an error was made in choosing the right size piece to create the hinge between the mounting and the tail. so a bit of a change of design is needed.

In looking through the store for suitable pieces of metal, Steve suggested that using some smaller size box steel would work well if we added a second piece that created a triangle. So we cut 2 long pieces of box steel for the main tail body and then a 3rd 300mm length to be used to bolt the tail on to.

A few more cuts to do with a hacksaw and some edge cleaning and its ready for welding.

Another large part of the tail is the plywood fin. Don suggested that we should make the tail in the shape of the EWB Cardiff logo, I like that idea. Need to get hold of a sheet of marine plywood.

3rd Stator hole
Due to misplacing of one of the wires in the stator, we needed to move one of the mounting holes out a bit. Steve pointed out that there was still enough room on our mounting plate to move the hole out a bit. Especially using an 8mm bolt.

Sunday, 19 October 2008

Assembly and some Wind Spinning action!

The moment came nearly two weeks ago now when we had everything ready to assemble the blades, alternator and mounting.

Alternator assembled, blades on the front a few more bolts to add.

We had a temporary stand that we used for the societies fair on hand, we mounted the turbine on the stand and table so that it was high enough to let the blades spin. We took the turbine in to the alley behind Suneils garage, there was quite a wind blowing through it acting like a very effective wind tunnel, once we gave the blades a quick spin to start them spinning the wind really got a hold of it, it started spinning really quite fast! A major milestone!

And a video of it spinning:

Wind turbine test 1! from Trystan Lea on Vimeo.

The Mounting

The mounting sits on top of the tower, it holds the alternator, blades and tail together and enables the whole assembly to rotate to face the wind.

To make the mounting, the first step was to find some steel. Luckily Engineering had all the steel piping, angle and flat bar that we needed . Next we cut the steel to the correct lengths and prepared for welding. We were very fortunate to have Malcolm an expert welder from the department who welded the parts together for us:

The Alternator

One of the great things about making a wind turbine from scratch is making the alternator, Its quite surprising finding out that it is possible to build something your self that generates a useful amount of electricity.

The alternator is able to produce 500W of power and is of the axial flux design were 2 magnet rotors each containing 12 strong magnets rotate either side of a stator which contains 10 coils.

The Stator
The coils were coiled by hand, each coil has 80 turn of enamelled copper wire in it. Here's a picture of myself, Ben and Paul making one of the coils:

Once all the coils were wound they were all connected together. One wire end of each coil connects to the ring neutral. The other wire is routed out of the stator to be connected to the rectifiers.

The coils are all cast in fibre glass resin which keeps the arrangement of coils in the required ring shape. The resin also makes the stator very durable. Picture is of Don taking the mould apart which is quite a task:

The Rotors
Each rotor consist of 12 strong neodymium magnets stuck to a steel disk. A jig is used to fit them all in the correct position.

Each rotor is encased again in resin in addition to making them more durable the resin holds the magnets in place stopping them from flying off. Picture is of Sylvie, Don and myself pouring in the resin mix:

One of the rotors being taken out of its mould:

In order to assemble the alternator, the mounting is needed I will detail that next.

Making the Blades

One of the first stages in building the turbine was to make the blades. The blades were carved out of wood, we used pine from a wood supplier just up the road from engineering. Each blade is carved out of a 1200mm x 150mm x 37mm plank.

The shaping is done in 4 principal stages.

1) Cutting the tapered shape - thick base, thin tip.

2) Carving the twisted windward face

Picture: Sylvie sanding down the twisted windward face of a blade and Mathew marking out a magnet mould.

3) Carving the thickness

Picture: Paul carving the thickness, luckily we had an electric plane to make this a bit easier.

4) Carving the curved shape on the back of the blade.

5) Cutting out the blade disks and fitting it all together.

Picture: Don holding the finished blades held together by the blade disks and quite a few screws.


If your reading this for the first time, welcome to the EWB Cardiff Wind turbine Blog! This blog is to serve as a record of what we do each week and how far we have got on the turbine. Hopefully it will mean that everyone involved can keep up with progress and that anyone interested can see what we are doing and get involved!

Last year 2007/2008 we started a project to build a wind turbine. We followed a design developed by Hugh Piggott of Scoraig Wind. The design has been used in development situations and by self-builders around the world. The all important manual:

The turbine has a blade diameter of 2.4m. Every part of the wind turbine is built from scratch. The blades are carved out of wood. The alternator is built from 24 permanent magnets mounted to 2 steel disks and 10 hand wound copper coils cast in resin. The blades and alternator and tail are attached to a welded steel mounting which sits on top of the tower.

We have currently finished carving the blades the alternator and the mounting. The next step is to make the tail, the tower and the electronics before we take it up in to the hills for testing!