Storing Cookies (See : http://ec.europa.eu/ipg/basics/legal/cookies/index_en.htm ) help us to bring you our services at overunity.com . If you use this website and our services you declare yourself okay with using cookies .More Infos here:
https://overunity.com/5553/privacy-policy/
If you do not agree with storing cookies, please LEAVE this website now. From the 25th of May 2018, every existing user has to accept the GDPR agreement at first login. If a user is unwilling to accept the GDPR, he should email us and request to erase his account. Many thanks for your understanding

User Menu

Custom Search

Author Topic: Faraday paradox revisited,magnetic field rotation question.  (Read 56507 times)

PolaczekCebulaczek

  • Full Member
  • ***
  • Posts: 160
Faraday paradox revisited,magnetic field rotation question.
« on: August 05, 2016, 10:09:24 PM »
hello

I decided to start this topic because I want to summarize all we know about Faraday disk paradox in one topic on this forum, this may be helpful for further homopolar generator study.The most important question is "Does magnetic field rotate with magnet or not?"
let's consider a situation like this :

A coil is wrapped around a magnetized core (cylinder magnet). Both the coil and magnet are rotating together around the axis of the cylinder. Will current be induced in the coil?
This permanent magnet is ceramic, not iron; this should stop any induction taking place inside the metal body of the magnet.(if magnetic field does not rotate) This will simplify things and eliminate unwanted effects.

anyone tried this configuration?


Magluvin

  • Hero Member
  • *****
  • Posts: 5884
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #1 on: August 06, 2016, 04:02:40 AM »
I see where you are coming from here. Most likely the windings will have to have more angle from top of the mag to the bottom in order for the fields to cut the windings properly. At 90deg is best, but if the windings are tight, each turn is more closer to 0deg. Higher angles would mean less turns and less voltage out.

I like the config though. If the widings have more than 0deg angle, there should be something. Being it is one magnet and it is not dragging the mag field around like bunches of mags, the field should remain still like a big disk. But only if the magnets field is uniform. I have some neo mags that the poles are not center, as in stronger off to one side than the other. So that may be an issue.

Ive seen guys use a bunch of little magnets in order to try and recreate a large disk mag. But the reason it does not work is we need the magnet to be one piece. When the magnet is a big rin disk with a hole, like a speaker magnet, as the magnet spins on axis, the field doesnt spin or move in rotation with the magnet, so if the copper disk spins with the magnet, the field cuts the disk and you get output. Using a bunch of small mags to make the disk screws all that up.

Ill see if I have my old drawings of what I thought may work. It was alternating mag disks where there would be say a N/S pole ring magnet goes on the shaft first, then a copper disk, then another N/S magnet(in attraction to the first mag) then an iron disk and then a S/N magnet in repulsion to the second mag ring. The iron disk should capture the 2 S fields and direct them to the shaft where the fields have a path to the other poles without breaching the outside diameter. This way we can add another copper disk that carries current inward, where the first copper disk carries current outward. Then we can have a stack of mags n disks that we can make electrical connections from an out disk to an in disk at the outer edges which will give us a bunch of plates in series, in, out, in, out, etc to increase the voltage like more windings would do.

Mags

 

Gothic

  • Guest
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #2 on: August 06, 2016, 07:33:11 AM »
The most important question is "Does magnetic field rotate with magnet or not?"

anyone tried this configuration?

Hello PolaczekCebulaczek

   I think this resembles what you have there, just applied in a differrent fashion.
   and a youtube video, prolly nothing new to the forum but interesting nonetheless.
     https://www.youtube.com/watch?v=gduYoT9sMaE

minnie

  • Hero Member
  • *****
  • Posts: 1244
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #3 on: August 06, 2016, 12:55:36 PM »



  Methinks it's all about frames of reference.

PolaczekCebulaczek

  • Full Member
  • ***
  • Posts: 160
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #4 on: August 06, 2016, 04:42:51 PM »
Quote
If the windings have more than 0deg angle, there should be something
i hope so...

the brushes its a thing, they are stationary ,they should be welded to the disk when everything rotates together, would be a current then?
if magnet spins and disk is at rest there is no current in disk so magnet field must not rotate with magnet right?

can you give my a schematic for simple amplifier that will light up a led when small DC current is detected? I will try to build this.

ceramic magnet is important because of this: (I also wish to see no brushes version, wires welded to magnet!)


minnie

  • Hero Member
  • *****
  • Posts: 1244
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #5 on: August 06, 2016, 06:33:10 PM »
 
  Disc rotation relative to return path.



lumen

  • Hero Member
  • *****
  • Posts: 1388
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #8 on: August 10, 2016, 06:28:38 AM »
and we still dont know if the field rotate or not.

It's not important if the field rotates with the magnet or not. The problem results from a uniform field where because it's uniform will simply slide and do no work.
It must be forced to cross a conductor to induce a current and yet because of this it still produces the counter emf.
If it did not then a simple unipolar motor would not operate. A unipolar motor rotated by a mechanical input will become a generator for the same reason.

The principal of counter EMF is what makes all motors and generators work.

The instant any current is produced in a conductor by movement through a magnetic field, that very same current generates an opposite magnetic field that fights the movement direction.



minnie

  • Hero Member
  • *****
  • Posts: 1244
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #9 on: August 10, 2016, 10:07:39 AM »



  Look at a speedometer, what more than a rotating magnet?
          John.

PolaczekCebulaczek

  • Full Member
  • ***
  • Posts: 160
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #10 on: August 10, 2016, 07:40:51 PM »
ok but when magnetic field is moving trough space it produces inducted electric field right? according to Faraday, charged test charge should experience a force near spinning magnet like so:

so field is moving with magnet but no induction in stationary disk??

lenz is lenz ,lorentz is lorentz but there should be non zero current detected in disk.

minnie

  • Hero Member
  • *****
  • Posts: 1244
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #11 on: August 10, 2016, 08:41:21 PM »



  In the case of something like the speedometer there are "Small rotating eddies"
  set up within the disc.
          John.

lumen

  • Hero Member
  • *****
  • Posts: 1388
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #12 on: August 10, 2016, 11:12:55 PM »
Once you consider all the cases of a Faraday generator you will see the problem.

How about: Magnet stationary but disk and contact spinning = no charge?

Then you see it's only the difference between the disk and contact that matters.

The magnet makes no difference if it rotates or not. Why is that?

It's because the uniform field of a magnet on it's axis will remain stationary OR rotate whichever produces no work.
It's only when the field is trapped between a rotating disk and stationary conductor OR stationary disk and rotating conductor that the field must cut through one or the other objects and work is performed.
It is in fact forced to cut through the conductor or disk the same as a normal generator uses the force of the magnet itself to push it's field through a conductor.


PolaczekCebulaczek

  • Full Member
  • ***
  • Posts: 160
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #13 on: August 12, 2016, 01:57:16 AM »
Quote
he magnet makes no difference if it rotates or not

but what about electric field detection when magnet is spinning by test charge near it? its there or not?

lumen

  • Hero Member
  • *****
  • Posts: 1388
Re: Faraday paradox revisited,magnetic field rotation question.
« Reply #14 on: August 12, 2016, 03:35:21 AM »
but what about electric field detection when magnet is spinning by test charge near it? its there or not?

The charge will exist the same as if the detector were rotating around a stationary magnet.
A charge separation exists when something moves through a magnetic field even if the field is of constant intensity.
If a current flows then there is resistance to the movement, unless the field is constant in which case the field is pushed along to prevent current flow.
If the uniform field is trapped between two conductors and is forced to cross one or the other, then again the current causes increased resistance.

In any case you need to be careful not to cross the field twice as the field is circular and the return of the field through the conductor will cause a charge in the opposite direction and cancel any effect.

Maybe do some experiments and see what you discover.