Dual Axial Flux Generator & Wind Turbine

Mission:

To make energy generation accessible with 3D printing.

Story:

I had been selected to join the International Antarctic Expedition (IAE), ClimateForce: Antarctica, that equips leaders with resources and actionable solutions to become a part of a global force of change.

This expedition gave me the ability to learn from experts on the subject of climate change as well as equip myself to be in a position to create an impact back home.

I wanted to use this opportunity as a platform to promote the use of 3D printing to give access to renewable energy to as many people as possible. Even though the maximum output if this generator is 50-100W, it can act as a blueprint for others to get into improving manufacturability of wind turbine or generator designs. Maybe this could inspire some college students who take up this project to pursue renewables as a career.

This generator was used in Antarctica along with CFA2018 and the organisation 2041 to generate power and power our electronics. It goes to show the resilience in 3D pritned parts and what amazing things this technology can do in the future and play and important role in creating a sustainable future.

What is a Dual Axial Flux Generator?

A dual axial flux generator consists of powerful magnets placed on either side of a fixed stator winding, like a sandwich creating a very strong magnetic flux between them, and thus inducing a powerful EMF in the stator winding. Since the magnetic flux is axial to the output shaft, it is an axial flux generator, unlike a radial flux generator like that most commonly found in DC motors that are converted as dynamos.

I chose to build this kind of generator, since it creates a dense magnetic field and makes the most efficient use of the magnets. There is hardly any magnetic flux leakage outside the generator itself.

Another upside is that, it makes the generator flat, and is easy to construct, as well as integrate into power generation projects.

Assembly:

Jig Preparation:

The winding jig is used to wind the coil. The Jig and the Jig holder are fastened together using M3 fastners.

Coil Preparation:

The jig is mounted on a power screw driver/drilling machine using a HEX bit. There is a notch on the jig to indicate when the maximum number of coils are reached.

Try and maintain a constant level of tension on the coils to get a roughly same number of coils. 6 coils will need to me made like this.

Use kapton tape to keep the cool from unwinding. Keep the kapton in place on the inside of the coil, and wind on top of it.

There is a hole on the jig where the start of the coil is placed. As long as you use the same convention for winding, and placing into the coil holder, you should be alright, only the polarity of the DC would change.

To Do: Automate this process with a encoder and counter to be more accurate.

The HEX bit used to mount on the drilling machine can be seen below. After winding is done, fold the Kaptop tap on top of each other and remove the coils

Coil Placement:

Place the coils inside the Coil Holder/ Stator. There are three pins inside which the coils will sit.

The "IN" and "OUT" of the coils where the winding started and ended need to the placed in the appropriate notches. These will help identify how the coils would be wound.

Coil Housing Preparation:

Glue gun the coils in place.

Star Topology Arrangement:

Connect the phases in a delta pattern. There are 2 Coils for each phase. The coil on the opposite sides are of a single phase.

Connection coils of the same phase in series first, the "OUT" of the first coil with the "IN" of the second coil of the same phase.

Then connect all the remaining "IN"s of the three phases together which would be the common ground. All the "OUT"s will be the three phase output.

In the below images, I covered the coils with the stator cover, and marked the IN's and OUT's of the coils to aid wireing.

Rotors:

The picture below shows of the rotor stacks up into an assembly. The magnets get embedded into the magnet housing, and is covered by a laser cut sheet metal cover. The sheet metal cover prevents magnetic flux of the powerful magnets from going out of the generator, and also makes the flux stronger on one side of the Magnets.

The rotor brace prevents the powerful magnets from collapsing into each other, as well as provides a way to mount the drive shaft. Use M3x16 CSK screws to mount everything together.

Dynamo Housing Preparation:

The generator now comes together. Using the bearing housings, the generator cover and M4 rods cut to length.

Application:WindTurbine

The below video shows the initial tests. The generator outputs DC via a 3 Phase rectifier.

3D Print the gears that can be mounted on the output shafts of the generator. We couple the generator to a 3D printed Axial Flux turbine design (https://www.thingiverse.com/make:167496) To couple the generator to this, we 3D print gear hub to replace the default one.