I tried to build a small dynamo and failed

[Drone Zell]

I'm trying to make a small, magnetic induction generator and I keep failing. I'm a noob at this and would highly appreciate some help.

My first attempt was a simple tube with copper wire around it, and a magnet that I tried to spin inside the tube to generate electricity.

First tube attempt: https://i.ibb.co/VCvzQnY/Whats-App-Image-2020-05-08-at-14-10-01-4.jpg

Magnets I was using: https://i.ibb.co/Vw0TB4y/Whats-App-Image-2020-05-08-at-14-10-01.jpg

The copper wire is 0.3mm thick and the magnets are neodymium. The cylinder magnets' polarity is at the top and bottom. The rectangle magnets' polarity is on the sides.

After my first attempt, I noticed I'm generating some energy by pushing the magnet in and out of the tube, but not when the magnet is spinning inside. I then read a bit and thought my problem was that the copper wire was wound horizontally instead of vertically. So I made this second tube:

https://i.ibb.co/jrMvPFL/Whats-App-Image-2020-05-08-at-14-10-01-2.jpg https://i.ibb.co/k2BwYLW/Whats-App-Image-2020-05-08-at-14-10-01-1.jpg

And it still looks like it generates a little bit of energy when the magnet goes in and out instead of spinning. It's such a small voltage I have to go to the 200m portion of the voltage-meter to see anything.
I can spin the magnet very fast (with an electric drill) and I only get like 00.2 or 00.3, but when I try to push it in and out I get bursts of 00.8 - 2.00. (I don't even know if that's in Volts).
That's with the rectangle magnet, the cylinder magnet only generates a bit of electricity when pushed in and out, and nothing when it spins.

Can anyone please help me? What am I doing wrong? How can I build this so it will generate as much energy as possible with the magnet spinning inside?

Thanks a lot for your time :)


What am I doing wrong? I just want to be able to power a small LED or something.

[Rob Beckers]

Hi Drone,

Interesting project!

Magnets and wire generate electricity proportional with the CHANGE in magnetic flux through the windings. So just moving a magnet around, without causing the magnetic field going through the windings to change, won't do a thing.

That would be an explanation for your first experiment; the same windings see the same magnetic flux as you spin that magnet around. There's no change in flux. When you move the magnet(s) in from the top and out the bottom there is of course a fairly large change in flux, from zero, to some value, then it reverses, and down to zero again as the magnet comes out the bottom. Change in flux, therefore electricity.

Similar issues happen with the round magnets that have their poles at top/bottom. Spinning them does not make a change in flux happen through those windings in both scenarios you describe.

Now, the flat magnets spinning inside your last experiment could work, if you wired those coils differently. Right now all those coils are in series, so as the flux decreases in one it increases in the next, and overall the coils catch the same flux. No change, no electricity. If you had just one of those 6 coils connected individually and you spun that flat magnet around inside you'd likely see much more happening.

With the 6 coils you can of course make more by properly connecting them together, such that those coils seeing the SAME change in flux are in series. That would give you AC output, as not all those coils are going to see the same flux change happen at the same time. You can rectify AC into DC and do stuff with that.

Try one coil in your last experiment (so cut the wire connecting to the next coil). That should give you some AC coming out. Be sure to set your meter to AC when measuring.

-RoB-

[Dave Schwartz]

Perhaps a silly question... you are using 'magnet wire'? It looks like there may be some kind of fuzzy coating in some places but its hard to tell. Magnet wire has a clear lacquer insulation coating. If this is plain bare wire most of the coils are probably shorted.

[Drone Zell]

Hi Drone,

Interesting project!

Magnets and wire generate electricity proportional with the CHANGE in magnetic flux through the windings. So just moving a magnet around, without causing the magnetic field going through the windings to change, won't do a thing.

That would be an explanation for your first experiment; the same windings see the same magnetic flux as you spin that magnet around. There's no change in flux. When you move the magnet(s) in from the top and out the bottom there is of course a fairly large change in flux, from zero, to some value, then it reverses, and down to zero again as the magnet comes out the bottom. Change in flux, therefore electricity.

Similar issues happen with the round magnets that have their poles at top/bottom. Spinning them does not make a change in flux happen through those windings in both scenarios you describe.

Now, the flat magnets spinning inside your last experiment could work, if you wired those coils differently. Right now all those coils are in series, so as the flux decreases in one it increases in the next, and overall the coils catch the same flux. No change, no electricity. If you had just one of those 6 coils connected individually and you spun that flat magnet around inside you'd likely see much more happening.

With the 6 coils you can of course make more by properly connecting them together, such that those coils seeing the SAME change in flux are in series. That would give you AC output, as not all those coils are going to see the same flux change happen at the same time. You can rectify AC into DC and do stuff with that.

Try one coil in your last experiment (so cut the wire connecting to the next coil). That should give you some AC coming out. Be sure to set your meter to AC when measuring.

-RoB-

Thanks a lot! That sounds exactly like what I needed. I'll definitely try to run it with only one winding out of the six and see how that goes. However, I didn't quite understand how to properly wind the 6 together. Do you just wind 6 separate threads and connect them at the end? Is it just one continuous thread that has a different order?

Another question, If I had 2 magnets facing south to south, instead of 1 magnet... would that change anything?

Also, is there a special setting on the meter for the AC? (Is it the one that says "A"?)

Thanks a lot again!

[Drone Zell]

Perhaps a silly question... you are using 'magnet wire'? It looks like there may be some kind of fuzzy coating in some places but its hard to tell. Magnet wire has a clear lacquer insulation coating. If this is plain bare wire most of the coils are probably shorted.

Yes, I'm using copper wire with clear lacquer insulation coating, just removed the coating from the tips to connect to the meter's cables.

[Rob Beckers]

Thanks a lot! That sounds exactly like what I needed. I'll definitely try to run it with only one winding out of the six and see how that goes. However, I didn't quite understand how to properly wind the 6 together. Do you just wind 6 separate threads and connect them at the end? Is it just one continuous thread that has a different order?

Another question, If I had 2 magnets facing south to south, instead of 1 magnet... would that change anything?

Also, is there a special setting on the meter for the AC? (Is it the one that says "A"?)

Thanks a lot again!

The "A" probably stands for "Amp", that's current. I don't know your meter, there should be a way to switch between AC and DC. In a larger sense though, and respectfully, you really need to do some reading/studying if your electrical knowledge is currently at the level of "what does the A stand for". There's no need to get a degree in electrical engineering, but a basic knowledge will make life a lot easier if you want to play around with alternators, generators, and other things electrical. I've not looked, though there should be plenty of basic tutorials/courses on the Web.

How windings can be connected together depends on which ones see the same flux change at the same time. Only then will they produce a Voltage waveform with the same polarity, magnitude, and phasing. That in turn depends on the physical location of those coils and the magnets. There are 'recipes' that have layouts of magnets and windings that are known to work. A little Internet searching will bring them up.

Connecting coils in series increases the output Voltage, connecting them in parallel increases the output current.

Have fun!

-RoB-