Why is there no EMF induced in this circuit?

[Baluncore]

You need to stop and think.
You are still wasting our time.

State clearly if you will, or will not, use brushes.
State clearly why you are wanting to do this.

Brushes, commutators and slip rings have been the bane of electromagnetic engineering since Faraday. One big advance was when Tesla developed the induction motor. Since then, permanent magnet rotors have appeared, and that has further eliminated brushes.

The biggest homopolar generators still have brushes, and the brushes are the most difficult part of the engineering. If it was topologically possible to build a homopolar generator without brushes, some genius would have thought of it over 100 years ago.

 

[doomer]

You need to stop and think.
You are still wasting our time.

State clearly if you will, or will not, use brushes.
State clearly why you are wanting to do this.

Brushes, commutators and slip rings have been the bane of electromagnetic engineering since Faraday. One big advance was when Tesla developed the induction motor. Since then, permanent magnet rotors have appeared, and that has further eliminated brushes.

The biggest homopolar generators still have brushes, and the brushes are the most difficult part of the engineering. If it was topologically possible to build a homopolar generator without brushes, some genius would have thought of it over 100 years ago.

Yes, but I want to know why brushes are necessary, if the center wire is causing trouble then why not use a ring magnet on top of copper disc and insert a mu metal pipe aka magnetic shielding in the center of such magnet to shield the center wire from magnetic field and rotate everything with load.I need pictures with vectors that show opposing forces, want to know how the brushes resolve the canceling exactly.
I've got a little advice for you:

"If you can't explain something in simple terms, you don't understand it" - Richard Feynman

 

[berkeman]

I've got a little advice request for you:

Fixed that for you.

 

[hutchphd]

u:

"If you can't explain something in simple terms, you don't understand it" - Richard Feynman

If you have a loop of wire and a loop of field to (dis)connect them one needs to cut the field line (Faraday) or cut the loop (contact). They need not be done simultaneously. Simple Chinese rings

 

[Baluncore]

I need pictures with vectors that show opposing forces, want to know how the brushes resolve the canceling exactly.

I have explained it in simple terms, but you have not understood it.

You are missing a solid and reliable foundation to electro-magnetics, and have many preconceptions, some of which are wrong. So I have no idea which way you might jump next, or what I might have to disabuse you of.

You seem to think that by making it more complex, you will understand it more easily. That is well illustrated by your placing the short bar-magnet, under the disc.

Judging by your 2D diagrams, you do not think in 3D, which is a major handicap where an inherently 3D cross-product is involved. I believe that would explain your problematic understanding of the need for brushes.

 

[doomer]

I have explained it in simple terms, but you have not understood it.

No, you didn't explain it in simple terms or even not at all, because that would require drawing opposing forces vectors and you didn't do that. "it's canceling because disk moves " - this is not enough.

You seem to think that by making it more complex, you will understand it more easily. That is well illustrated by your placing the short bar-magnet, under the disc.

Placing a small magnet under the disc so the field won't cross the wires is making things more complicated? nice.

Judging by your 2D diagrams, you do not think in 3D, which is a major handicap where an inherently 3D cross-product is involved. I believe that would explain your problematic understanding of the need for brushes.

I do not believe that drawing force vectors in paint is an impossible task, 3d animation is not needed, this can be achieved by making few pictures but I can make 3d model as well but first I have to know what is going on.

First we should start from this: "Working principle of a homopolar generator: due to Lorentz force FL negative charges are driven towards center of the rotating disk, so that a voltage shows up between its center and its rim, with the negative pole at the center."
So disc is charged and brushes collect this charge (no canceling here yet) current flow from the edge to the center of the disc.
Is the disc also charged when there are no brushes?? if so then soldering wires to the disc is causing voltage doubling and canceling, now I want to see this opposing canceling vectors. I think that a need to see those canceling vectors is realistic and reasonable.

This forum exist to explain things, you can give up, stop answering my questions and assume that I'm retarded or whatever, that's fine, I will ask elsewhere till I find answers and diagrams.

 

[doomer]

If you have a loop of wire and a loop of field to (dis)connect them one needs to cut the field line (Faraday) or cut the loop (contact). They need not be done simultaneously. Simple Chinese rings

By contact you mean brushes in faraday disc? If I place magnet on a wire and short this wire via switch, would I get some emf?

 

[Baluncore]

Placing a small magnet under the disc so the field won't cross the wires is making things more complicated? nice.

Yes. If the magnetic field lines do not cut the wire, then they must plunge back through the disc. The two passes, in different directions through the disc, cancel.

If it does not have a parallel vertical magnetic field, it is not a homopolar generator.

Your diagram does not show if the wire rotates with the disc, or where there might be brushes. Before the diagram can be discussed, too many reckless assumptions have to be made, or too many combinatorial conditions must be given in an answer.

Let's see if someone else is game to try to satisfy your demands.

 

[doomer]

If it does not have a parallel vertical magnetic field, it is not a homopolar generator.

What a nonsense, it seems that you knowledge about homopolar generators is worse than mine.
Check the link, this is valid brushed homopolar generator with one magnet under disc and it works, perfect parallel vertical magnetic field is not needed

Your diagram does not show if the wire rotates with the disc, or where there might be brushes. Before the diagram can be discussed, too many reckless assumptions have to be made, or too many combinatorial conditions must be given in an answer.

Did you see arrow at the top? it shows rotation of the disc, is obvious that there are no brushes, the whole discussion is about no brushes variant, well, indeed maybe someone else will be better at explaining what is going on.

 

[berkeman]

Thread is paused for a bit...