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Author Topic: Magnet Myths and Misconceptions  (Read 605773 times)

vineet_kiran

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Re: Magnet Myths and Misconceptions
« Reply #195 on: October 12, 2014, 03:19:06 PM »
someone said in TA thread that magnetic field is move at ~60x speed of light, magnetic field is not static but i dont know he said that for PM or electromagnet (coil) or both. i can not recall his name.


Does it mean that massless entities can travel with a speed faster than light?   Even liquids and gases are  static when held in a container but individual molecules will be moving in all directions hitting the wall of container and we call it as 'pressure'.    Analogically is there anything like 'magnetic field pressure?'   



sparks

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Re: Magnet Myths and Misconceptions
« Reply #196 on: October 12, 2014, 07:13:36 PM »
     Does a conductor moving through a uniform magnetic field develop voltage between the ends of the conductor?  In a unipolar generator you can spin the magnets along with the disk.  What I believe is happening is that  the magnetic field aligns the electrons.   This counteracts the coulomb force trying to disperse the electrons.   The electrons on the inner part of the disk experience less change of position than the electrons on the periphery.   This creates a negative charged pole on the inner parts of the disk.  As you move to the periphery of the disk the electrons are moving and residing in that space for less time.  Entropy takes over and electrons move from the higher state of order to the lower state of order.   I would like to build one of these with an inner ring and an outer ring seperated by an insulator to prove this.

DreamThinkBuild

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Re: Magnet Myths and Misconceptions
« Reply #197 on: October 12, 2014, 08:39:44 PM »
Hi All,

Hi Sparks,

Here are some sources for what your describing. If a dielectric is spun between a charged capacitor plate the dielectric will become magnetic.

Henry Augustus Rowland, Rowland Effect (1887) - "...carried out a well-known research on the effect of an electrically charged body in motion, showing it give rise to a magnetic field."

reference: On The Electromagnetic Effect of Convection-Currents (1889)
https://archive.org/details/onelectromagneti00rowl

Wilhelm Roetgens Experiment (1888) - "...discovered in 1888 that a dielectric became magnetized when moving in a uniform electric field."

Paper: Electromagnetic Fields in Moving and Inhomogeneous Dielectrics, 2001

http://kth.diva-portal.org/smash/get/diva2:9054/FULLTEXT01

Rowland-Vasilescu Karpen's Effect

"A modern reproduction of this experiment consists in connecting a disk of hard rubber or an old phonograph record to the shaft of an electric motor. The disk is electro-statically charged by rubbing it with a piece of woolen cloth. Then, it is set in rotation and a magnetic compass is approached close to it. The needle is deflected; the faster the rotation, the greater the deflection."

source pg8: http://www.pprime.fr/sites/default/files/pictures/pages-individuelles/D2/germain/EPJP2013.pdf

Now there is also the reverse of this which if a dielectric is spun between a uniform magnetic field a +/- charge is built on the disc (linear polarization).

references:
On the Electric Effect of Rotating a Magnetic Insulator in a Magnetic Field, 1913
https://archive.org/details/philtrans08602085

Reverse W.C. Roetgens Experiment: Electrodynamics, Academic Press, 1955

This leads to more questions though.

We have an electrostatic generator which has a high voltage (large E-field) but low current (limited B-field).

Then a homopolar generator with high current (large B-field) but low voltage (limited E-field).

Is there a missing "Electropolar" generator which allows the B and E field to be balanced?

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #198 on: October 12, 2014, 09:26:16 PM »
     Does a conductor moving through a uniform magnetic field develop voltage between the ends of the conductor?  In a unipolar generator you can spin the magnets along with the disk.  What I believe is happening is that  the magnetic field aligns the electrons.   This counteracts the coulomb force trying to disperse the electrons.   The electrons on the inner part of the disk experience less change of position than the electrons on the periphery.   This creates a negative charged pole on the inner parts of the disk.  As you move to the periphery of the disk the electrons are moving and residing in that space for less time.  Entropy takes over and electrons move from the higher state of order to the lower state of order.   I would like to build one of these with an inner ring and an outer ring seperated by an insulator to prove this.

Sparks:

You are posing an interesting question but you are not posing the question properly.  You are not taking into account the direction of of the magnetic field and the orientation and direction of the conductor.  When it comes to magnetic fields, everything has to take direction into account.  Note that this has already been mentioned several times on this thread.  The implications are as follows:  That means that you have to start at square one, and learn the basics before you can seriously discuss and experiment with magnetic fields.  I have to assume that many people read your posting had the same issue and it did not occur to them either.  Some of those people have probably been discussing magnetic fields and magnetic interactions for years.

This is an opportunity for some of you to "hit the reset button" and discard all of your mostly incorrect preconceptions, misconceptions,  and superstitions about magnetic fields.  You can reread this thread and spend a week or two hunting around online for basic and intermediate course material on magnetic fields and pull yourselves up by your own bootstraps and educate yourselves.  It's all there for free.  In my opinion this is the real way to do it.  When you are "spoon fed" information  by passively reading it simply doesn't stick.

MileHigh

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #199 on: October 12, 2014, 09:38:11 PM »
Cangas:

I read your posting, and you repeated the point that I took issue with:

<<<
My post blatantly stated that FIELD LINES may or may not be real, and cannot be proved to either exist or to not exist per se.
>>>

But you have no evidence that they exist.  Anything "cannot be proved to either exist or not exist."  You are stating that anything is possible.  That is a hollow argument that goes nowhere.  It's like QEG fans saying that people have to "prove that the clainm does not work" when nobody has proved the claim does work.  The burden of proof is on Fix the Worldd and the QEG replicators to prove that it DOES work.  This is an old argument that has been around forever on the forums.  People have to prove that things actually work or that things actually exist.  Without that throught process, then things degenerate into a useless free-for-all.  Again, you can look at the example of the QEG.  Getting energy from the atmosphwere with an antenna, spark gaps, special separaate LC resonator, mechanical resonance with the core, 400 Hz, you must have good psychiological vibrations, it just goes on and on and it's just an exercise in futility and nonsense.

So I am NOT trying to be disagreeable, I am just making a firm point.

MileHigh

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #200 on: October 12, 2014, 09:59:09 PM »
TK:

<<<
But that is in fact _exactly_ what is happening. Where do the electrons come from in the cathode ray? THEY COME OUT OF THE WIRE that connects the cathode to the rest of the circuit. They are pushed through the wire by voltage... that is, the electric field, that comes from _individual unit charges_ pushing each other apart. That is what voltage IS !!!
>>>

We are going to have to agree to disagree.  The electric field does _not_ come from individual unit charges pushing against each other when it comes from a source of induced EMF.  The individual electric charges are being pushed around by an external electric field.  The source of the energy is the EMF field and the charges are just the "agents" of the field.  Again, I am talking about electromotive force here.  The power grid is all EMF-based.

Here is a thought experiment:  You have a transformer secondary driving a load resistor.  There are three setups.  The first setup has the output of the secondary at 10 volts RMS driving a 10-ohm resistor.  The second setup has a secondary output of 100 VRMS driving a 100-ohm resistor.  The third setup has a secondary output of 1000 VRMS driving a 1000-ohm resistor.

So, the secondary wire and the resistor are neutral with no net charge.  In all three cases the current is one amp RMS.  Is there any difference in the electron density between the three setups because of charges pushing against each other?  The answer is no, if you put a bunch of high-end current probes at multiple places on each setup they would all give you exactly the same current waveform.  If you could measure the free electron density in the metal it would be the same in all three cases.  Electrons are not "pushing against each other to make the current flow."  Granted, in each setup there is a "sea" of valence electrons "jumping around."  The electrons in the high-voltage setup are not jumping around at any higher energy levels relative to their nuclei as compared to what is happening in the low-voltage setup.  But they are at a higher relative potential energy due to the fact that they are at the "tips" of the EMF field inside the long coil of wire.

Now of course the EMF is happening inside the transformer, so what about the interconnect wires?  The conductive wire by definition prevents the existence of an electric field inside the wire.  But the fact that there is a low finite resistance in the wires means that there is a low level of EMF inside the wires also.  It's all in "harmony" - the coil, the interconnect wires, and the load resistor - they all have the "correct" amount of EMF/electric field strength so that the current flow is the same everywhere.  In that sense the electrons are not pushing against each other.  The EMF is everywhere in the circuit at just the "correct" level so that all is the electrons flow at the same rate.

MileHigh

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #201 on: October 12, 2014, 10:10:42 PM »
Another thought experiment:  What if the three coils are not connected to their load resistors?  One more time, let's ignore any electron flow due to parasitic capacitance.  Let's assume that you can observe the three coils in any manner without having to worry about the high voltage.  Let's assume that you are simply not looking at the voltage.  Will the three coils look any different from one another when you examine them in other ways?  I say that they won't, they will all look the same.

And just a reminder, all of this discussion is based on voltage induction, EMF.  I am not considering static electricity.  For static electricity, electron density does come into play.   I agree that in both cases you can measure voltage and the units are the same, it's the same voltage.  But there are fundamental differences with respect to the generation of EMF voltage and static-induced voltage.

Note that a capacitor bridges these two things.  An isolated capacitor has charged plates and that is an example of static electricity in action.  But when you connect a resistor across the capacitor, then I think that you can look at what happens in two ways that are mutually compatible.  You can say you have charges at high density pushing against each other and the charge repulsion will push the charges right through the resistor. Or you can say that you are back to EMF pushing current through the resistor because there is a strong electric field between the capacitor plates that also travels through the resistor.  When you connect a resistor across the capacitor plates, the electric field pushes the electrons through the resistor.

mondrasek

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Re: Magnet Myths and Misconceptions
« Reply #202 on: October 12, 2014, 10:59:50 PM »
To summarize what I have come to understand from this discussion regarding an EF:  Voltage is a concentration of charge.  And since the negative unit charge carrier is the (free) electron, that means that Voltage is the result of a concentration of electrons.

Electrons are all the same (negative) charge and so want to repel each other.  So Voltage is very much like "pressure" as used in the mechanical analogy.  IE when you have a group of electrons that are freely spaced so as not to be too close to each other they do not repel each other very much and so there is very little or no Voltage.  But if those electrons are forced closer together their same charge fields are repelling each other.  The repulsive "force" between all of those electrons is Voltage.  And the "compressed" field of electrons are very much looking for a route to relieve the "pressure" that they are under.  And so if given the chance to return to an area of lower electron density (lower charge potential) they will go there.  And the closer they are together, the higher the Voltage, and the higher the Pressure, and therefor with more "gusto" they will go to that lower potential.

Can the word "gusto" above be replaced with the word "Energy?"

This explains to me how static electricity works.  For instance, on the collector of a VDG there is created a very large group of extra free electrons.  And so the surface of the collector also has a high Voltage.  But when you give that very large electron source on the collector a place to go where there is a lesser concentration of electrons (allow it to spark to somewhere, ie. ground out) all of those extra electrons will "jump" to that place of lower electron concentration under a high Voltage (pressure).  However, the group of electrons in the static electricity filed (on the collector of the VDG) have absolutely no backup electrons to flow as quickly and with so much Voltage (pressure) after that initial jump.  And so there is very little CURRENT (flow rate of the electrons) behind that discharge.

Okay?

M.


Magluvin

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Re: Magnet Myths and Misconceptions
« Reply #203 on: October 12, 2014, 11:41:59 PM »
TK:

<<<
But that is in fact _exactly_ what is happening. Where do the electrons come from in the cathode ray? THEY COME OUT OF THE WIRE that connects the cathode to the rest of the circuit. They are pushed through the wire by voltage... that is, the electric field, that comes from _individual unit charges_ pushing each other apart. That is what voltage IS !!!
>>>



I had come to post just a quick pic of the coil and rotor, as Im looking for the proper hardware to mount to a pvc board base. And I read the statement above first and it has me reiterating my earlier post.....

In my mind, if the electron is the source of magnetic field effects, thinking on the lines of if the deflection coils in a cathode ray tube can attract or deflect an electron, then likewise the electrons in the beam must be a source of magnetic field distortion and orientaion, not just magnetic like iron where either pole N or S only pulls on them, so they must be so called magnets themselves.  Now when we read the quote above and take heed that it is true, then I have to say that electrons have a positive and negative side to them.  But these are not magnets as we know. They must be sort of like a cross section slice of say fine copper wire and the wire has DC current flowing through it.  So if we visualize the slice, say slice is as long as the width of the wire, for visualization, the field spins around the electron, and one flat side of the slice is positive and the other negative at all times.

So when we apply a dc source to the wire ends, the electrons in a straight piece of wire flow in one direction and the fields around the wire are also in the same orientation, then theoretically, I must conclude that the moving electrons in the wire are oriented + side facing the - source wire end, and the - side of the moving electron is facing the  + source end of the wire, therefore the magnetic orientation of each electrically affected electron in the wire are all the same. And that magnetic orientation can be reversed by switching the dc source on the wire in opposite polarity. ;)

And it is possible that the electrons that dont move in the wire can also be finally moved from their strongholds by applying more voltage/charge at the source, disrupting their 'atomic' magnetic hold to their copper atom counterparts and that disruption in the electrons field could break it loose from the atom and become mobile, till it finds an empty seat with another atom that is missing and electron, if the source charge effects allow it to do so at the time.

So this is what I am adding to this thread as part of the discussion. To me, it doesnt sound far fetched really.   And if it is so, what experiments could possibly prove it?  Possibly measuring the field around a DC arc, showing that the electron passing through space has correct magnetic field orientation. But if you put a mag close to the side of the arc, do the N and S of the magnet both produce pull on the arc? ;)

And possibly knowing that electrons have a positive and negative side to them, can that help us in any way? 

Just some things to think about.

Mags

Magluvin

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Re: Magnet Myths and Misconceptions
« Reply #204 on: October 12, 2014, 11:50:54 PM »
pic was huge, so deleted it.  Hadnt posted a pic from this camera in a while, forgot to shrink.

Mags

Magluvin

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Re: Magnet Myths and Misconceptions
« Reply #205 on: October 12, 2014, 11:54:54 PM »
deleted pic. was stretching screen even though I shrunk it.  :'(   Maybe gotta take a new one due to remanence in the server from first posting it large.


Mags

Magluvin

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Re: Magnet Myths and Misconceptions
« Reply #206 on: October 13, 2014, 12:20:57 AM »
I deleted the huge pic from the post on the last page, shrunk it, reposted above and the page is still stretched.
Ill try renaming it.

Mags

Pirate88179

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Re: Magnet Myths and Misconceptions
« Reply #207 on: October 13, 2014, 01:03:01 AM »
I deleted the huge pic from the post on the last page, shrunk it, reposted above and the page is still stretched.
Ill try renaming it.

Mags

That is a good idea, also, dump your internet cache which helps me most of the time something like this happens.

Bill

Magluvin

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Re: Magnet Myths and Misconceptions
« Reply #208 on: October 13, 2014, 06:02:31 AM »
Had some distractions, friends came over, and spent some time with the pic issue on my shop laptop.

Anyway, finished, but no testing tonight.

Mags

Dave45

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Re: Magnet Myths and Misconceptions
« Reply #209 on: October 13, 2014, 04:52:26 PM »
You always do good work
Is it a bifilar winding
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