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Author Topic: AC voltage from single magnetic pole  (Read 39119 times)

nix85

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Re: AC voltage from single magnetic pole
« Reply #90 on: October 09, 2020, 10:02:11 PM »
Abberation is half in + and half in -, thus it is perfectly usable.

But let's look at your marks. Indigo lines mark 90° from red lines.

56° would be just bit to the right from the middle.

Where are the yellow lines. 75-80°.

verpies

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Re: AC voltage from single magnetic pole
« Reply #91 on: October 09, 2020, 10:05:46 PM »
Question: Does the scope not represent at least a little bit of load on the coil, and wouldn't using a separate sensing coil similar to that used in the following video be a more accurate test? https://youtu.be/hw2bBYYHp34?t=89
Thank you.
No and Citfta's answer is correct.


This is because the impedance of the scope probe is so high that it is negligible at frequencies occurring in these mechanical machine Hz or kHz at most.
However if you were dealing with MHz frequencies or higher then the impedance of a typical scope probe would NOT be negligible anymore.  That's why in such scenarios active FET probes are preferred - they have an even higher impedance than passive scope probes.

...wouldn't using a separate sensing coil similar to that used in the following video be a more accurate test
Using separate coils for sensing the voltage and current is not more accurate and in my opinion it is not even necessary to resolve this issue, but it is cleaner conceptually and it is more difficult to object to the result of an experiment that uses separate coils for sensing induced voltage and induced current ...and since it does not skew the experiment much when identical coils are used, I just agree to it.

verpies

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Re: AC voltage from single magnetic pole
« Reply #92 on: October 09, 2020, 10:23:03 PM »
In the midtime, observe the phase shift without and with load in ordinary and bi transformer By Heins
youtube.com/watch?v=4_zgR5fyF30
Experiments involving transformers are not relevant to the issue at hand because transformers do not use single purely inductive circuits nor single RL circuits. They involve multiple RL circuits that are coupled magnetically.

The comparison of
the phase between the externally applied input voltage and the output current of a transformer,
is not the same as,
the phase between magnetically induced voltage and magnetically induced current in a single inductive circuit.

partzman

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Re: AC voltage from single magnetic pole
« Reply #93 on: October 09, 2020, 10:23:44 PM »
Nix,

Here is the source of the phase shift in the video you referenced.

A first test was made with a large coil for current sense with a flat voltage sense coil in parallel as in the test video.  This can be seen in the first pix.  A ceramic PM was passed in front of this assembly with the PM axis on axis with the coil assembly.  In the following scope pix we again see no phase shift.  CH1(yel) is the voltage and CH4(grn) is the current.

A second test was made with the same coils only now the current sensing coil was positioned at 90 degrees to the voltage sensing coil and the PM axis as seen in the third pix.  The PM was again hand passed in the same relative position as before and the 4th pix shows the resulting waveforms.  Here we see the source of the of the current lag in the video when one considers the positioning and timing of the PMs on the rotor to the coils.

This video therefore is no proof of your position IMO.

Regards,
Pm

nix85

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Re: AC voltage from single magnetic pole
« Reply #94 on: October 09, 2020, 10:26:57 PM »
Experiments involving transformers are not relevant to the issue at hand because transformers do not use single purely inductive circuits nor single RL circuits. They involve multiple RL circuits that are coupled magnetically.

The comparison of
the phase between the externally applied input voltage and the output current of a transformer,
is not the same as,
the phase between magnetically induced voltage and magnetically induced current in a single inductive circuit.

I did not post it as argument for anything, just as interesting video, curb your horses.

nix85

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Re: AC voltage from single magnetic pole
« Reply #95 on: October 09, 2020, 10:32:18 PM »
Nix,

Here is the source of the phase shift in the video you referenced.

A first test was made with a large coil for current sense with a flat voltage sense coil in parallel as in the test video.  This can be seen in the first pix.  A ceramic PM was passed in front of this assembly with the PM axis on axis with the coil assembly.  In the following scope pix we again see no phase shift.  CH1(yel) is the voltage and CH4(grn) is the current.

A second test was made with the same coils only now the current sensing coil was positioned at 90 degrees to the voltage sensing coil and the PM axis as seen in the third pix.  The PM was again hand passed in the same relative position as before and the 4th pix shows the resulting waveforms.  Here we see the source of the of the current lag in the video when one considers the positioning and timing of the PMs on the rotor to the coils.

This video therefore is no proof of your position IMO.

Regards,
Pm

Let's suppose you are about this video, but it does nothing to disprove the effect itself, it does not debunk Heins' delayed lenz coils.

It does not disprove the fact that higher in frequency you get inductors become more and more reactive. Etc.

90° shift is possible.

NdaClouDzzz

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Re: AC voltage from single magnetic pole
« Reply #96 on: October 09, 2020, 10:39:28 PM »
No and Citfta's answer is correct.


This is because the impedance of the scope probe is so high that it is negligible at frequencies occurring in these mechanical machine Hz or kHz at most.
However if you were dealing with MHz frequencies or higher then the impedance of a typical scope probe would NOT be negligible anymore.  That's why in such scenarios active FET probes are preferred - they have an even higher impedance than passive scope probes.
Using separate coils for sensing the voltage and current is not more accurate and in my opinion it is not even necessary to resolve this issue, but it is cleaner conceptually and it is more difficult to object to the result of an experiment that uses separate coils for sensing induced voltage and induced current ...and since it does not skew the experiment much when identical coils are used, I just agree to it.

Thank you for the reply.
Question: If using a sensing coil/s, would the current/voltage measured be that produced/induced in the sensing coil/s? I'm not sure if I'm asking this question correctly. For example, in a step-down transformer the secondary would have lower voltage/higher current. I'm wondering if using a sensing coil of say lesser turns than the coil you want to measure wouldn't cause some skewed results due to a change in voltage/current. I suspect that it would not make any difference in regards to phase. Thank you.
Regards

verpies

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Re: AC voltage from single magnetic pole
« Reply #97 on: October 09, 2020, 10:46:53 PM »
Which means you got too much resistance and capacitance in the circuit and you have proved nothing. Also you used way too low speed,
@ Citfta
You have not plugged all the "holes" in your experiment and now they are being used to undermine its validity.

inductive reactance is XL= 2πfL.
@nix85
True, but only in reference to external sinusoidal AC voltage applied to an inductor (of magnitude Vrms). 
In such scenario, the rms of AC current (redundant) flowing through this inductor is irms = Vrms / 2πfL  ...and for a square AC voltage applied to that inductor that current is  irms = πVrms/ 16fL.


However, the above is not true in case of applying an external alternating flux through that inductor.
Are you able to provide a formula for the alleged phase difference (θ) between the induced voltage and induced current in an inductor that is subjected to a sinusoidally varying external magnetic flux ?


nix85

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Re: AC voltage from single magnetic pole
« Reply #98 on: October 09, 2020, 10:54:21 PM »
Quote
However, the above is not true in case of applying an external alternating flux through that inductor.

So now you are not claiming only for ideal coil but for all coils over which external flux changes.

Do you realize Heins' delayed lenz motor works only due to the fact that reality is opposite to what you claim. Yea, i believe he uses cores, but nonetheless.

Also did you see the quote above about superconductors, do you see it is common knowledge inductance plays the same role as in resistive coils.. delaying current.

verpies

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Re: AC voltage from single magnetic pole
« Reply #99 on: October 09, 2020, 11:11:35 PM »
Nix,
This test was done using an air core coil arrangement that has L1 ~100 turn for the voltage sense coil with L2 ~20 turns wound directly on top of L1 resulting in a rather tight coupling of k~.95 or so.  A ceramic PM was moved by hand past the coil assembly with the resulting traces sampled on a Tek MDO using a Tek TCP0020 current probe for the current sense.

Ch1(yel) shows the voltage across L1 and CH4(grn) shows the current through L2 shorted.  It is obvious that the voltage and current are in-phase.
Thank you for performing this experiment but unfortunately you did not keep it clean enough and I suspect that now Nix will try to punch holes in it. He is entitled to do so, BTW.
Most likely he will object to:
- The period of the magnet's motion is too long compared the the L/R time constant of the inductive circuit.
- the speed is not controlled precisely enough. Is not uniform.
- the coils are not identical (this would also be an objection from me) or have the wrong number of turns.


...and finally my objection: The coils are in too close proximity. This allows the shorted coil to influence the flux penetrating the open coil used to sense the voltage.  As you probably know, a shorted coil opposes the flux which attempts to penetrate it. It pushes the change of the flux out of itself.



[/font]
If you would like any changes made to this simple test, let me know as I can wind any configuration you would request apart from an SC coil.
In My Opinion this would do:
1) Attach two identical magnets on the perimeter of a bicycle wheel, diametrically oppositely.
2) Place two identical air core coils around the wheel diametrically oppositely.
3) Open both coils and precisely calibrate their position such that their induced voltage signals are identical and in phase.
4) Close one coil and prepare it for current measurement.
5) The bicycle wheel can be spun by hand but the i&v measurement must be made only when it is spinning down by itself (by its moment of inertia).
6) Repeat the experiment with the roles of the coils reversed, i.e. close the voltage sensing coil and open the current sensing coil.

verpies

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Re: AC voltage from single magnetic pole
« Reply #100 on: October 09, 2020, 11:16:17 PM »
Your link is not working.  But it appears you are trying to change the subject again.  We are NOT talking about transformers.  We ARE talking about a magnet inducing voltage and current in a coil. 
Yes, transformers are at least 2 magnetically coupled inductive circuits and we are talking about about a magnet inducing voltage and current in a single inductive circuit.
This transformers are a different subject.

verpies

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Re: AC voltage from single magnetic pole
« Reply #101 on: October 09, 2020, 11:22:31 PM »
It's funny how you try to prove he's right with resistive coils while doing the test wrongly forgetting he is making a claim for PURELY INDUCTIVE COIL.
I never narrowed it down to purely inductive coils only, although I claim this for purely inductive coils as well. Just read the text of my 1 BTC challenge.
I do however narrow down the lack of delay between the induced voltage and induced current to coils which are energized magnetically - not electrically !


@ Partzman
I do not want you to make experiments which are designed to prove my point.  Only the truth.

nix85

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Re: AC voltage from single magnetic pole
« Reply #102 on: October 09, 2020, 11:33:09 PM »
I do however narrow down the lack of delay between the induced voltage and induced current to coils which are energized magnetically - not electrically !

Already addressed this above, if you were right Heins' motor could not work.

Also what they say about sc at stackexchange.

verpies

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Re: AC voltage from single magnetic pole
« Reply #103 on: October 09, 2020, 11:50:55 PM »
Here is one bench test showing clear 90° IV phase shift with aircores.
From description
"In this configuration the little flat coil with negligible inductance read only voltage and detect the position of magnets, the other coils are closed in loop and read the current across one shunt resistor of 10 Ohm. "
https://www.youtube.com/watch?v=m6AOTQlHhTU&
This experiment is very flawed because:
1) It is comparing voltage induced in one coil to current induced in 3 other coils connected in series .
2) Not only the number of coils is different but their number of turns in the two sets of coils is wildly different, too.
3) Some coils are oriented differently with respect to the diameter of the rotor.
4) It is not proven that the magnets influence all coils equally and at the same time, because ...see pt.5
5) There is no calibration run performed, which demonstrate that when the two sets of coils are open then the voltage waveform induced in them is identical and in-phase.
6) The coils are in too close proximity to each other so the coils shorted by the current sensing resistor (CSR) can influence the flux attempting to penetrate the open coil which is used to sense the induced voltage.  View this simulation to see how a low-resistance coil distorts the varying magnetic flux in its vicinity.  The coil in this simulation is not superconductive but in this one it is.


Because of these reasons this experiment is not conclusive.






partzman

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Re: AC voltage from single magnetic pole
« Reply #104 on: October 09, 2020, 11:52:32 PM »
I never narrowed it down to purely inductive coils only, although I claim this for purely inductive coils as well. Just read the text of my 1 BTC challenge.
I do however narrow down the lack of delay between the induced voltage and induced current to coils which are energized magnetically - not electrically !


@ Partzman
I do not want you to make experiments which are designed to prove my point.  Only the truth.

Verpies,

I have tried to be as objective as possible with my testing and will take your build suggestions into consideration.  At the moment however, I have a relative who recently fell and broke a hip, had surgery done, and now appears to have had a stroke.  I may not be able to continue with this thread for awhile.

Regards,
Pm