A theory and build inspired by Friedrich Lüling's magnet motor

[kajunbee]

Cadman if the pic is to large please delete.

[Cadman]

Thanks for the input and ideas guys.

Citfa, that's a good idea. I actually have a couple of those, but unfortunately they are  3 and 5 spoke pulleys so won't work for this. I'll make a note of it and keep my eyes open for one.
Too bad we all don't have our own foundries and machine shops.

Lota, I have used black sand with epoxy before but it's magnetic attraction is in between iron PLA and the iron 100. At least the ones I cast were. Maybe I used too much epoxy?
It's cheap though and may do alright for a build. I might cast a couple with a different binder and see how they do.

Kajunbee, the pic is alright for my screen but you should try to size for 1024 max width. Guilty of that myself.
BTW, earlier you mentioned leverage. Leverage is a factor used in this build in a couple of ways. You'll see.

Regards to all,
Cadman

[kajunbee]

There's always a trade off and I wasn't seeing it at first.
There is more leverage near the center but there is also reduced velocity. So the rotor near the magnet will be in the sticky point for a longer duration.
Not sure if there's a workaround for this or not. Maybe a smaller air gap between the two rotor arms. Not sure. Also since eddy current drag needs to be considered I was thinking a laminated steel rotor might work. But ideas are great until you see the price tag.

[Cadman]

There's always a trade off and I wasn't seeing it at first. There is more leverage near the center but there is also reduced velocity. So the rotor near the magnet will be in the sticky point for a longer duration. Not sure if there's a workaround for this or not. Maybe a smaller air gap between the two rotor arms. Not sure. Also since eddy current drag needs to be considered I was thinking a laminated steel rotor might work. But ideas are great until you see the price tag.

Yes, laminated electrical steel would be great but it's too expensive and difficult to get so it's out for now. Looking at your drawing it appears you have a magnet at the center of the rotor.
Just so everyone knows, there are no magnets on or in the rotor in this experiment. The rotor is all iron.

[Cadman]

More stuff has been delivered, almost ready to cast a rotor and assemble some test pieces.

You can see in the first drawings 2 magnet switches have to be physically moved.
Closing the switches isn't a problem because the motor magnet's natural attraction will power that.
But opening 2 at the same time is going to take a lot of force, even with a sliding top shunt on the magnets.

Kuling used air cylinders to operate the switching system but I really want to avoid that or any kind of electrical device if at all possible.
So, this experiment will have a mechanical roller cam system to open and close the switches at the proper time.

There is a big problem with that idea though, because the force needed to open the switches
will be greater than the motoring force of the rotor, and will probably break plastic parts too.
So in order for it to work some system has to be devised to increase the rotor force or decrease the force required for opening.

I see no way to increase the rotor's relative power so the only alternative is to decrease the opening force. 
That doesn't sound practical but the required force can be somewhat counter balanced with a mechanical spring system
to lessen the load on the rotor.

The drawback with that idea is the force curve of a magnet is exponential.
Off the shelf springs don't fit the bill very well because their forces are linear and end up soaking up too much power at the wrong times.
The only solution that I could think of is to come up with a spring that has an exponential force curve similar to the motor magnets.
If the operating force can be evenly counter balanced through the entire switch movement then we are home free!

Last night a practical solution presented itself to me, one that anyone can make, and will be incorporated into the build if it works.
What can exactly counter a magnet's exponential force curve?
Another magnet!

No secrets.

Regards

edit: Reading what was written it looks like I'm taking credit for the solution. Just the opposite, it's sarcasm.
All this time I've been trying to bull through the problem with springs and the solution has been staring me in the face.
I was just too focused on springs to see it.