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Author Topic: Magnet Myths and Misconceptions  (Read 605816 times)

tinman

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Re: Magnet Myths and Misconceptions
« Reply #375 on: January 04, 2015, 11:15:13 AM »
Tinman if the magnetic field were null at the dipole center as the Figure 8 claim requires then there would be nothing opposing the earth's magnetic field and the compass needle would align to the earth's field perpendicular to the dipole that is on the east-west line.  Try the experiment.  You will find that the conventional view prevails.
Like i said-the compass needle is only being attracted to the strongest magnetic attraction force/fields. Of course if i move the PM far enough away,the needle will point to magnetic north,otherwise we'd have a compass that points to every ones magnets. Im guessing at this point you are not going to draw the three simple diagrams i asked of you,despit the fact that i have done endless experiments for you and others,not to mention the cash forked out. How much time would it take you to do this? If three is to much,then draw just one electromagnet and it's(what you call)field lines,and flow direction arrows.-->Is this to much to ask?.

MarkE

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Re: Magnet Myths and Misconceptions
« Reply #376 on: January 04, 2015, 12:41:18 PM »
@MarkE

I would like you to take some time and draw up an electromagnet the shape of a rod magnet-say 3 inches long and 1/2 inch in diameter for the core material. This will of course have the conductive wire wrapped around it. You will need 3 pictures/diagrams of this very same electromagnet. I would then like you to show the magnetic field building up around that electromagnet in three stages from the instant a current is applied to the inductor-i want to see this magnetic field build around the inductor. I know this happens at or close to the speed of light,but lets devide that by 3.
So we will have in the first diagram the field just starting to emerge,then the second diagram will show it half way built to its full potential,and the third will show the full field and strength of that field. I will then show and explain why there is no magnetic field at the cenetr point of that inductor/electromagnet between the two pole's.

I have done many experiments for you and others,so i hope you can take the time to draw these 3 simple diagrams.

P.S-you may use your fictional lines of force,and flow arrows for this experiment.

Brad
Depending on what is used for the core, the timescale will have to be much, much longer to see anything worthwhile.  We cannot instantaneously change the current in any circuit.  We can apply voltages with very high dV/dt's and once the voltage builds to a large value then the di/dt can become big.  The current will then build as long as we allow until ultimately being limited by the combined coil and circuit resistance.  Depending on the core material, the net magnetic field will either track the current (air core, or approximately with high resistance core), or lag due to eddy currents.  Both situations are depicted below.  If you are concerned with transmission line effects, then a wound coil masks those.  If you want to see something interesting in ns time frames then modeling a microstrip trace over a ground plane will do the job.  If you are going to measure transmission line effects at ns and ps scales then you will need an expensive time domain reflectometer.

MarkE

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Re: Magnet Myths and Misconceptions
« Reply #377 on: January 04, 2015, 12:48:16 PM »
Like i said-the compass needle is only being attracted to the strongest magnetic attraction force/fields.
No the compass needle is acted upon by the vector sum of all fields it is exposed to.  Any misalignment with the net field imposes a torque on the compass needle that in the steady state it will closely align.
Quote
Of course if i move the PM far enough away,the needle will point to magnetic north,otherwise we'd have a compass that points to every ones magnets.
Which is exactly why an experiment where we place the test magnet orthogonally to the earth's magnetic north-south line.
Quote
Im guessing at this point you are not going to draw the three simple diagrams i asked of you,despit the fact that i have done endless experiments for you and others,not to mention the cash forked out. How much time would it take you to do this? If three is to much,then draw just one electromagnet and it's(what you call)field lines,and flow direction arrows.-->Is this to much to ask?.
Done in the post above.

tinman

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Re: Magnet Myths and Misconceptions
« Reply #378 on: January 04, 2015, 01:08:07 PM »
So the below pic is depicting the magnetic field as you know it?

MarkE

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Re: Magnet Myths and Misconceptions
« Reply #379 on: January 04, 2015, 01:19:19 PM »
So the below pic is depicting the magnetic field as you know it?
As it is for a solenoid coil or bar or cylinder PM magnet magnetized through its legnth.

tinman

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Re: Magnet Myths and Misconceptions
« Reply #380 on: January 04, 2015, 01:28:11 PM »
As it is for a solenoid coil or bar or cylinder PM magnet magnetized through its legnth.
Below is a pic,and we have a thin pancake coil that can slide from one end of the electromagnet to the other(electromagnet passes through the center of the pancake coil). We are supplying the electromagnet with a DC wave current(like an AC wave,but with a 0 to 6 volt P/P) Where would the maximum voltage(maximum amplitude) be achieved over the 100 ohm resistor- point A,point B or point C.?

MarkE

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Re: Magnet Myths and Misconceptions
« Reply #381 on: January 04, 2015, 01:47:20 PM »
Below is a pic,and we have a thin pancake coil that can slide from one end of the electromagnet to the other(electromagnet passes through the center of the pancake coil). We are supplying the electromagnet with a DC wave current(like an AC wave,but with a 0 to 6 volt P/P) Where would the maximum voltage(maximum amplitude) be achieved over the 100 ohm resistor- point A,point B or point C.?
You have built a transformer.  The coupling coefficient will be highest at the center of the dipole where the magnetic field is nearly perfectly perpendicular to the pick-up coil as opposed to the ends where the field curls substantially.  Depending on the time scale, there could be a big difference between the 0-6V-0 ... voltage waveform and the current waveform.  As to where you will get the maximum reading across a 100 Ohm or any other specific value resistor load depends on among other things the impedance match between that resistor and the reflected impedance back to the power source.  If you want to find out where the field is the strongest, then you need a variable resistor load.  You would then adjust that resistance to find the maximum power point at each location and then compare those power levels to find where the coupling is greatest.

tinman

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Re: Magnet Myths and Misconceptions
« Reply #382 on: January 04, 2015, 01:59:42 PM »
You have built a transformer.  The coupling coefficient will be highest at the center of the dipole where the magnetic field is nearly perfectly perpendicular to the pick-up coil as opposed to the ends where the field curls substantially.  Depending on the time scale, there could be a big difference between the 0-6V-0 ... voltage waveform and the current waveform.  As to where you will get the maximum reading across a 100 Ohm or any other specific value resistor load depends on among other things the impedance match between that resistor and the reflected impedance back to the power source.  If you want to find out where the field is the strongest, then you need a variable resistor load.  You would then adjust that resistance to find the maximum power point at each location and then compare those power levels to find where the coupling is greatest.
Cool
Now please tell me why we generate no power from an inductor if we place the core of that inductor in the center of a magnets dipole on a rotor. So picture a rotor with PM's around it so as the dipole center of the magnets are in the center of the perimeter of the rotor,and we would have what we know as north on the top surface of the rotor,and south on the under side of the rotor.If the magnetic field is nearly perfectly perpendicular to the pick-up coil as you stated,why is no power produced by the inductor/generating coil?.

tinman

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Re: Magnet Myths and Misconceptions
« Reply #383 on: January 04, 2015, 02:02:38 PM »
You have built a transformer. 
Yes,i know i have built a transformer. But this one we can move the secondary along the field produced by the primary.

poynt99

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Re: Magnet Myths and Misconceptions
« Reply #384 on: January 04, 2015, 03:52:48 PM »
Below is a pic,and we have a thin pancake coil that can slide from one end of the electromagnet to the other(electromagnet passes through the center of the pancake coil). We are supplying the electromagnet with a DC wave current(like an AC wave,but with a 0 to 6 volt P/P) Where would the maximum voltage(maximum amplitude) be achieved over the 100 ohm resistor- point A,point B or point C.?

You will obtain the highest voltage reading at point B, but not because of maximal coupling. It comes down to net flux.

At the ends of the coil, positions A and C, the net flux passing through your pickup coil will be significantly lower than what passes through in the middle. The reason being because at the ends, the curling flux has not diverged that much, and most of it will pass through the pickup coil. Therefore, there will be two flux paths (roughly the same net magnitude) passing through the pickup coil, but in opposing directions, largely canceling each other out.

In the middle position point B, the flux density outside the coil is significantly lower (due to the curl) so there will be a higher net flux passing through the pickup coil in this case.

In both cases, all the flux generated within the coil diameter passes through the pickup coil.

synchro1

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Re: Magnet Myths and Misconceptions
« Reply #385 on: January 04, 2015, 05:52:42 PM »
http://overunity.com/15309/reboot-is-the-delayed-lenz-effect-real-or-just-a-misunderstanding/msg428891/#msg428891

@MileHigh,

I can help! I live on Calle Hidalgo in Jaco, Costa Rica. Try and bring your own cowardly ass down here for a fist fight!

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #386 on: January 04, 2015, 06:03:16 PM »
@MileHigh,

I can help! I live on Calle Hidalgo in Jaco, Costa Rica. Try and bring your own cowardly ass down here for a fist fight!

http://overunity.com/15309/reboot-is-the-delayed-lenz-effect-real-or-just-a-misunderstanding/msg428894/#msg428894

Dave45

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Re: Magnet Myths and Misconceptions
« Reply #387 on: January 04, 2015, 06:11:11 PM »
We need to understand where we are trying to get energy from.

What is the geometric configuration of a field line.

What are eddy currents and how do they react to the field line.

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #388 on: January 04, 2015, 06:23:12 PM »
Tinman:

Good on you for stating the obvious:  There is no Bloch Wall at the center of a magnet.

You stated that there is no magnetic field alongside the center of a long bar magnet.  MarkE showed you how you can do a compass test to confirm that there is a magnetic field there.  I think the mistake that you are making is that you will not feel any attraction at the center of a long bar magnet if you place a piece of ferrite or metal in that place.  You can have situations where there is no attraction felt and there still is a magnetic field present.  It's because the magnetic field is parallel to the magnet and there is no net pull towards either pole on the ferrite or piece of metal.  It's the same thing for the iron filings.  The majority of the iron filings are not attracted to either pole of the magnet.  The majority of the iron filings experience what looks like a linear magnetic field.  They line up with the magnetic field to "fall" into their position of minimum magnetic potential energy but they are not pulled towards either pole.

Here are two clips about deriving the magnetic field for a solenoid:

https://www.youtube.com/watch?v=4c6fRmyh4q8
https://www.youtube.com/watch?v=ZBXVuHpUucc

MileHigh

MileHigh

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Re: Magnet Myths and Misconceptions
« Reply #389 on: January 04, 2015, 06:35:47 PM »
Chris:

I guess that you have left this thread.  I just wanted to comment again how sad it is that you can only draw parallels to other situations to supposedly back up your claim that there is a Bloch wall at the center of a bar magnet.  It even started to get loopy when you showed pictures of ferrofluid in action as "proof" of the existence of a Bloch wall.

You really did not advance your case at all.  What you tried to show was not scientific at all, and yet you claimed that you were the one being scientific.

You have built up walls around yourself with respect to this Bloch Wall nonsense.  I asked you repeatedly to explain what was going on in the magnet itself and you failed to do that.

This reminds me of cases where someone's understanding of a coil has been corrupted by the Bedini gang.  You try to explain to them what is going on when the coil discharges and they just put their blinders on and cover their ears and say, "radiant energy."  Or they say things like the pulse is "just voltage and no current" when in fact by definition the pulse is a pulse of current.

Do what you want to do, but at this point it's almost like you are a poster boy for how to go about doing things the wrong way.  You have been corrupted by non-scientific cheap pulp pseudoscience and that's most unfortunate.

The longer you keep playing with circuits, the more you start to see how things fit less and less into your electronics pseudoscience world.  Hopefully one day that will hit critical mass and you will realize the error of your ways.

MileHigh