Axial flux generator

Overview of my project of an axial-flux generator.

Axial-flux generators are very efficient dynamos in generating electricity.
The reason they are much more efficient in comparison to traditional dynamos or alternators, is that they make optimal use of the magnetic flux passing through the coils especially when the rotors with the magnets are on both side of the coils and the magnets are attached on a iron disk redirecting the magnetic fields one way ( through the coils).

In comparison - traditional alternators often are radial flux -meaning the magnetic fields are orientated outward causing the speed of these alternating magnetic fields to be quit low relative to the coils. The coils have a iron core to more efficiently distribute the magnetic flux through the whole coil enhancing induction through copper wire but putting a drag on the torque force of the turbine driving the rotor with magnets. This make them less efficient overall.

Axial flux alternators don't have this problem.

Here is how o make them:
This is a one phase alternator by the way.

I winded the copper coils and connected them in opposite direction so clockwise and counter clockwise.
When winding the coils it's importamt to make sure all of them have the same amount of turns, in my case 120 turns each. Otherwise it would create noise in the output current

After this is done it should look like this in the image below (a one phase stator)

After I solder them al together I connected the circuit to the terminals this can be some big screws. Make sure however they are conducting properly since some do have a non conductive protective layer.

Then you need to make a molt for the stator. It should like this:

We are going fill this with epoxy resin. Top the resin of with a fiberglass mat and put a top cover (lid )on it. Make sure the molt is tightly screwed upon the bottom and top so no or minimal resin is going to leak out of it. This is where the long screws are for you see in the images.

In the image the resin already hardened and I had remove the top cover of the molt

The resin takes approximately 24 hours to harden.
After this I removed the screws which took a little force. but they will come loose from epoxy.
Then the stator can be removed from the molt and it should look like this:

Now I did cut a disk out of a iron plate to mount neodymium magnets on.
These magnets should be alternating between their north and south poles which will create alternating current in the coils later on.
So attach each magnet on its opposite pole relative to the previous so north - south - north - south. In this case it was a one phase alternator containing 8 coils so i also needed 8 magnets.

Me in my workshop cutting out the iron disks

Because the iron plate was thin (1,2 mm) the magnetic fields still came through the iron on the other side so I did cut out 4 disks in total. With the second disk mounted it didn't attract any peaces of iron like paperclips, so this was sufficient.

I also cut two plastic disks for the protection iron disk against oxidation. These I mounted on top is the disks.

I taped edge of the disks with duck tape and putted resin over the iron side of the disk with magnets on it. This glued everything together from the magnets, the two iron disks and the plastic disk. It also protects the magnets and iron disk against oxidation.

Then when it had hardened I drilled 4 holes through the rotor blades to mount them on the spacer.
Without a proper spacer the rotor blades will attract each other and collide with the stator in between with a extremely strong force.
Note to be very cautious and store these rotor blades far away each other when not mounted. And during mounting on the spacer be very careful for your fingers.

The spacer consist of 5 (3mm) plastic disks which fits well within the stator cavity without creating friction during rotation.
It has also 4 screws on the edge of the stator to mount the generator on something such as a rooftop and 4 screws that not only connects the spacer with rotors but also a turbine or anything else that drives it that could be mounted on it.

It produced 10,5 V / 2A at 500 RPM. The highest I reached turning it by hand. With actual wind turbine or perhaps a spinning cycle attached to it, it could properly reach way higher voltages enough to charge car batteries and laptops.

The dimensions of this one 16cm diameter, 12 cm high.
Weight is 1,5 kg

I hope to be able to make a bigger one in the future which could create some serious output.
It will contain a 3 phase stator with 24 coils and 32 magnets.

But for now it was a nice project.