Simple generator

[broli]

The generator has been built for a while but sadly it didn't run very smooth to say the least. One of the lessons learned was that magnets can be too strong and using Neo's can be overkill in a lot of cases. I used waaay to little steel for the flux to be fully captured so the setup was leaking flux all over the place, it looked liked I was using a non ferro metal at times, the magnets were that overpowering, and causing massive eddy current on the bearings. Concerning the bearings I also learned that when the load is mainly axially you are better off using thrust bearings to avoid massive friction. Regular bearings are designed for radial loads not axial loads.

Anyway after this setback I decided to return to the fight. I settled on a relatively "cheaper" design to built. A toroidal core that is only wound for 180°. It's funny how I discovered how similar it looks to this concept:

http://overunity.com/1463/toroid-magnet-generator/#.V2fjRTVBHBw

Yet noone wondered what would happen if you only used one coil instead of both fighting each other's flux and forcing it out of the core causing it to interact with the rotating magnet. Using a single coil there should be no reason for the generated flux to escape the low reluctance core. But reason is not enough when it comes to violating established laws there we experiment.
I won't go into detail to as to why it is designed that way but it doesn't take a genius to figure it out.

In fact it's currently being built.

[broli]

Here's a small update, I haven't made the whole assembly yet but out of curiosity I did a quick and dirty run just spinning it by hand.

https://www.youtube.com/watch?v=vgl0-wF2t8M

It's surprising to see the signal, it almost looks like a square wave, you don't expect that from an electric generator.

[gyulasun]

Hi Broli,

Thanks for the update. Do you have permeability data for the toroidal core used? Just curious, trying to understand the squarewave-like waveform. If you have an L meter, would you check coil inductance without and with the magnet in place at some position?
Does this induced waveform change when you have some kOhm resistive load across the output coil?

Gyula

[broli]

The core is standard silicon steel with a strip thickness of 0.23mm. I have an L meter but atm the magnets I used are not the final ones, also the gap distance of the stator core and rotor magnets is too big now as I can't get them too close before they jump to each other. I'll be doing that when I have stator and rotor rigid.

Also I had an assumption and it looks like FEMM confirmed it, the simulation shows almost a triangle like waveform for the flux through the coil over time. This thus should give a square wave like shape for the induced voltage as the below graph shows.

This is quite interesting if you think about it because the interaction between the coil and magnet seems to be only taking place at the edges of the coil, meaning if the magnet is small enough and the disc sufficiently large the coil and magnets interact for only a few degrees and the rest of the way it keeps on changing the flux but the magnets are then so far away from the edges that they no longer interact with it.

[gyulasun]

Thanks for the details. Though I thought that saturation could not be a ruling factor in the induced waveform
but I did not think the flux changes like a triangle wave and this results in a square wave-like induced voltage waveform.

I wonder What may cause the coil interact with the magnets only at its edges. Common sense suggests
the coil cannot have definite poles at its two edges when wound onto a closed ring core. Can you explain that?