Magnet Myths and Misconceptions

[allcanadian]

I thought I would throw this out to everyone here for consideration.
Now at the beginning of this thread poynt99 suggested that a magnet had no transition point near the field center. I would agree with the notion that a magnet may have an aggregate polarity internally relating to magnetic domains however I would disagree that the external field reflects this line of thought and what is depicted in every textbook.


I found the image below a few years ago at this site: http://physicsworld.com/cws/article/news/2008/apr/08/new-probe-measures-magnetic-fields-inside-solids.


I should also state that I had mapped the magnetic fields of many magnet shapes using an Arduino/labview interface and a purpose built Hall Effect Array many years ago. The image below peaked my curiosity because my hall effect mapping was almost identical to the image I have illegally copied or not found below but that is neither here nor there.


Now you know I just have to ask the question?, which is why most everything I know disagree's with Poynt99's thought's concerning the magnetic field. I'm not pointing fingers or saying anyone is right or wrong here... persay. I'm just saying I find it fascinating that two intelligent and well educated people could come to such different conclusions.


I will let everyone here decide which is obviously a bad choice and I hope Poynt99 chimes in because I believe we all want the same thing despite our differences in opinion. We all want the truth and my truth would seem to be very different than the common consensus. So yes poynt99, you started this thread let's get it on and see where it leads us.


AC

[Magluvin]

@Mags... ok, I see. Yes, it makes sense. And I have a new little homopolar motor that I'll be showing in a little while myself, nothing new but perhaps a little different than what is normally shown.

Here's something for you to try: But you have to use a saturable-cored toroid for this. Instead of having the rotor and toroid in the same plane, mount the axle of the rotor along a diameter of the toroid, so that they are at right angles. Then you will have the rotor magnets "cogging" at the closest approach to the toroid... and then if you pulse the toroid, it will saturate the core and reduce the rotor magnet attraction for as long as the pulse is on. You can turn this effect into a motor drive. It's the basis of the Steorn Orbo, actually, what I call a CEPM, core effect pulse motor, a very interesting critter, it operates not on repulsion or attraction, but by reducing attraction as the magnet moves away from the "cogging" position.
Good luck, I will be very interested in what you come up with. I'd love to follow along on my own but I can't maintain the necessary tolerances with my present restricted toolkit.

Thanks T.   Yes I am familiar with the orbo principle.     

https://www.youtube.com/watch?v=FrtGzxOKpwQ&list=UUjjcpZL8tkpn4WGkU2y_lPQ

And, maybe you hadnt seen the Orbonbon solid state orbo that I created about 2 months before Naudin had shown his solid state version....  There was a thread back then discussing solidstate orbo possibilities, and this is what I had come up with.

https://www.youtube.com/watch?v=9Ljx1py-BUs&list=UUjjcpZL8tkpn4WGkU2y_lPQ

https://www.youtube.com/watch?v=JYXU_ClBrIA&list=UUjjcpZL8tkpn4WGkU2y_lPQ

It was about the size of a bonbon.     I gave it a name as you had the Orbette. 

Back to the subject.

What Im thinking is just like Faraday showing 1 wire wants to move when current is applied to it while it is perpendicular to the pole of a magnet, im trying to have a succession of wires next to each other with current flowing in all of them in the same direction but the magnet moves instead. Like I said earlier, the toroid coil may have caused issues with continuous spin due to the concentration of field within the core(plastic, air, etc) vs the field outside the winding in the opposing direction.  I had many thoughts before fiddling, as to the possibility that the field within the toroids core could possibly pull the magnet around, or the field outside the winding would pul the rotor the other way. Get it?    But I got strange results. So we will see those results when I straighten out the rotor balance issue and make a vid of that. Then Ill make the vertical wires setup after.  With all the many vertical wires in parallel around the rotor. Ill try current limiting for dc input and pulsing input like used in a very low ohm switching supply primary to eliminate the current limiting.

Im interested to see what you have come up with here also.

Mags

[Magluvin]

I thought I would throw this out to everyone here for consideration.
Now at the beginning of this thread poynt99 suggested that a magnet had no transition point near the field center. I would agree with the notion that a magnet may have an aggregate polarity internally relating to magnetic domains however I would disagree that the external field reflects this line of thought and what is depicted in every textbook.


I found the image below a few years ago at this site: http://physicsworld.com/cws/article/news/2008/apr/08/new-probe-measures-magnetic-fields-inside-solids.


I should also state that I had mapped the magnetic fields of many magnet shapes using an Arduino/labview interface and a purpose built Hall Effect Array many years ago. The image below peaked my curiosity because my hall effect mapping was almost identical to the image I have illegally copied or not found below but that is neither here nor there.


Now you know I just have to ask the question?, which is why most everything I know disagree's with Poynt99's thought's concerning the magnetic field. I'm not pointing fingers or saying anyone is right or wrong here... persay. I'm just saying I find it fascinating that two intelligent and well educated people could come to such different conclusions.


I will let everyone here decide which is obviously a bad choice and I hope Poynt99 chimes in because I believe we all want the same thing despite our differences in opinion. We all want the truth and my truth would seem to be very different than the common consensus. So yes poynt99, you started this thread let's get it on and see where it leads us.


AC

Interesting.    lets say there were lines of force just for example. Also for example sake, N and S have a flow direction, from N(outside the magnet) to south. So in the pic you have shown, the field line exits the N and enters the S.

I can imagine that a N out field line may not just be attracted to only the S pole, but can loop back toward any part of the side of the magnet as if it were a bunch of little magnets(domains) in a row or  train of little magnets. Especially the N field lines exiting the N pole close to the outer ends of the face of the N pole, and the lines from the center of the pole possibly go out the furthest and end up reaching to the S pole side of the mag. Like if we break or cut the magnet in half, each will have the same magnetic orientation as the original. So your pic makes perfect sense to me as compared to just the N field line turning all the way back to just the S pole. 

As with a coil, there just might be the same circumstances. Not sure.

Mags

[allcanadian]

check your pm, personal messages

[CANGAS]

The magnetic field produced by a current-carrying wire is _around_ the wire and you can visualize it as circular loops of field. Polarity is "direction" of the loops, there aren't really "N" and "S" poles to a circular field line or the field itself. The conventional direction of electricity flow is from the positive pole of the source to the negative pole. So if you point your right thumb in this direction along the wire and curl your fingers around the wire, the fingers will be describing the "direction" of the magnetic field around the wire. And you can demonstrate this with a magnetic compass. Believe it or not, for at least 20 years after electricity was being demonstrated in the laboratory, people did not understand that there was a magnetic field associated with current-carrying wires. The story is that it was actually discovered by accident during a classroom demonstration intended to prove that there was NO field around the wire, by Oersted in 1820.
http://en.wikipedia.org/wiki/Hans_Christian_%C3%98rsted#Electromagnetism
Inside the battery, there is a lot of electrochemistry happening and there isn't really a large coherent region where electron current flows. If you had small enough and sensitive enough instruments you could find net magnetic fields inside batteries, but you can demonstrate for yourself that batteries and ordinary magnetic fields don't interact much, by bringing a strong magnet near to a battery that is powering something.

"Dose it change from one end to the other-from positive side of the battery to the negative side. Or do we have a monopole field?" Neither one. The field is constant all along the wire and there is no such thing as a "monopole" magnetic field. You can arrange magnets, as in Halbach arrays, so that you only _see_ one polarity outside the bulk structure, but you can be assured that every field line emitted by the thing is in fact a closed loop that has no terminations. DivB=0.

Now it should be plain that if you have a field that is like onion skin shells around the straight wire, if you coil the wire into a solenoidal coil, the "shells" reinforce and add, and you now get a structure that makes "poles", where one end of the solenoid has a lot of field line "directions" coming out, and the other  end has field line "directions" that go in, and they loop completely through and around the whole solenoid. Again, the in and out are conventions, nothing is really flowing along the "lines of flux" of a magnetic field, unless you put it there.

Tink (this is simply a convenient way for me to use less keystrokes to refer to you, if you are in the least offended I will gladly do something else); you are doing OK till you get to the last sentence.

Again, the in and out are conventions, nothing is really flowing along the "lines of flux" of a magnetic field, unless you put it there.

I explain. Using the lines of flux, or, lines of force, as our mutually agreeable arbitrary model, we do need to visualize something as flowing on the lines. Momentum. The direction of the lines of force is a reliable indicator of the way in which momentum is transferred between one magnetic body and the other body which is being influenced. The imagining of an in and out flow of momentum along field lines is a necessary consequence of the use of "field lines" as an arbitrary visualization aid.


CANGAS 88*

*Hey look at me, I'm like the first rock n roll song Rocket 88.