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Author Topic: Gold Magnet, Earth Magnetic Field, Spin-Orbit Coupling, Polarity Free Repulsion  (Read 780 times)

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You are completely wrong to link these effects using rotating magnets with my writings.  The devices I considered do not use rotating fields.  I tried to point this out tp you but you seem fixated on the perception that creating unusual levitation MUST involve rotating fields, but you are wrong.

Smudge

No problem. It doesn't look like I am welcomed here.  I'll just go elsewhere.

Que/Gravock
   

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The magnet is "floating" (skating) on the paper. ...
The friction of the magnet between the paper and magnet provides a force that opposes the attraction to the magnet.

The magnet doesn't need a 'table' to stay on the isopotential because its own angular momentum converts the inward pull into a circular orbit at constant speed.
If that were true then this spinning magnet would follow such orbit even if it was floating on water in a styrofoam boat.
   

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No problem. It doesn't look like I am welcomed here.  I'll just go elsewhere.
Just because someone disagrees with you scientifically, do not mean that you are not welcomed.
Ask Smudge to provide evidence for his position, e.g. to define the force vectors that this device exerts on a small conductive disk, which is much smaller then the embedded copper/silver ring.
   

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Just because someone disagrees with you scientifically, do not mean that you are not welcomed.
Ask Smudge to provide evidence for his position, e.g. to define the force vectors that this device exerts on a small conductive disk, which is much smaller then the embedded copper/silver ring.

Smudge said I am "fixated on the perception that creating unusual levitation MUST involve rotating fields, and I am wrong".  However, this is not true.  I do not think rotating fields MUST be involved.  I'm actually extremely interested in SME and the devices he has considered, which doesn't involve rotating fields.

Smudge also said in another thread,

With Larmor precessions of course I see rotation, and close to each precessing particle I see a rotating field.  But in bulk material where there is no coherence the rotating fields do not appear external to the material, so we can't use them.  But we can use a temporary change in overall magnetzation when the precession angle is temporarily forced to change.
...
...
...

Smudge

As you can see, this isn't about a disagreement.  This is about his writings and the devices he has considered, which do not use rotating fields, as shown in the below quote.  I fully understand his position.  This is his bench and his writings.  However, this topic is about the electron spin itself, and not just limited to his writings.  If not, I can respect this (no hard feelings either way).  However, upon his request, you chose not to put the "gold dust" in the dust bin thread on the basis it was related to electron spin. My linking to the effects of rotating magnets is also related to electron spin.  However, Smudge wanted the effects of rotating magnets to be thrown in the dust bin as he did with the master magnet (gold dust).  I'm not here to cause division and I'm also not here to be belittled.

You are completely wrong to link these effects using rotating magnets with my writingsThe devices I considered do not use rotating fields.  I tried to point this out tp you but you seem fixated on the perception that creating unusual levitation MUST involve rotating fields, but you are wrong.

Smudge

The spinning magnet setup is a classic demonstration of Larmor Precession and Orbital Magnetic Motion. The effects are primarily due to the magnet's intrinsic angular momentum (its physical spin) interacting with the external magnetic field.  The underlying physics is nearly identical for both the master magnet and the orbiting spinning magnet. A smaller magnet spins because it's interacting with the changing field of a larger magnet. The conductive disk creates its own temporary "magnet" (via eddy currents) which then tries to align with or "chase" the moving field of the electromagnet. In both cases, the asymmetry of the field (provided by the copper ring/larger magnet) converts a pulsating force into a continuous rotational torque.

The "Wobble" (Larmor Precession): When the small magnet spins, it gains angular momentum. The large magnet exerts a torque on the small one, trying to align its south pole with the large magnet's north pole. Instead of flipping instantly, the small magnet precesses (wobbles).  The specific combination of axial spin (counter-clockwise) and orbital rotation (clockwise) is a result of the Lorentz force and the conservation of angular momentum. The magnet "skates" along the isopotential because it is the path where its potential energy remains constant.  The fact that the axial spin and orbital rotation are in opposite directions is a macro-scale analogy to how orbital and spin angular momentum can couple in an atom. In quantum mechanics, this is known as Spin-Orbit Coupling. This experiment is a great classical analogy of the "effects" of electron spin,

The underlying physics is nearly identical for both the master magnet and the orbiting spinning magnet.  It's also nearly identical to the effects of rotating magnets that I linked to.  A smaller magnet spins because it's interacting with the changing field of a larger magnet. The conductive disk creates its own temporary "magnet" (via eddy currents) which then tries to align with or "chase" the moving field of the electromagnet. In all three cases, the asymmetry of the field (provided by the copper ring, or the larger magnet, or the rotating magnets) converts a pulsating force into a continuous rotational torque.

We have gradient-based eddy current forces in the master magnet. The relative size of the object changes the "net" force between repulsion (Lenz's Law) and lateral dragging (the shifting field).

We have three specific behaviors occurring, based on the size of the non-ferrous metal:

1. Large Object (Dominant Repulsion).
When the metal is larger than the copper ring, it intercepts a massive amount of the primary magnetic flux from the electromagnet.  The large surface area allows for massive, circulating eddy currents to form across the entire face of the metal.  This results in an "opposing" magnetic field generated by the metal to be stronger than the localized "shifting" effect of the copper ring. The primary interaction is axial repulsion, it wants to push away from the magnet entirely.

2. Matching Size (The "Trap" or Attraction).
When the metal is roughly the same size as the ring, it becomes "captured" by the localized field gradient created by the ring.  At this scale, the metal "sees" the difference between the unshaded and shaded poles clearly. The copper ring creates a region of lagging flux. As the magnetic field sweeps across the pole, the metal is constantly "chasing" the peak flux density.  This creates a centering force. Because the field is effectively "pulling" the metal toward the shaded portion and holding it there through the cycle, it appears to be attracted to the center of that ringed assembly rather than being blown away.

3. Small Objects: (The "Motor" Effect).
When the metal is much smaller than the diameter of the ring, the field appears almost uniform across its small body, but with a high "phase gradient."  The small object acts like a tiny "squirrel cage" rotor. The magnetic field isn't just pushing it, it is rotating underneath it.  Because the object is small, the torque (turning force) becomes much more significant than the linear "push" or "pull".  The small piece begins to rotate or spin in place as it tries to synchronize with the sweeping field of the shaded pole.

Summary of Scaling Effects:

Metal SizePrimary ForceVisual Behavior
LargeBulk RepulsionPushed away from the magnet face
Diameter-MatchGradient CaptureHeld/Attracted to the ring center
SmallAsymmetric TorqueSpinning or orbital motion


The torque causing the small non-ferrous metal to spin is similar in principle to the two-magnet interaction, as both involve the alignment of two magnetic vectors. In the copper ring scenario, a "sweeping" or rotating magnetic field induced by the ring causes eddy currents in the metal, which then attempt to catch up with the field, creating a spin. This "induced torque" acts on small, low-inertia objects similarly to how a permanent magnet's field causes another to turn, with the primary difference being that the magnetic field is created through induction rather than being intrinsic to the small object.

A small conductive disk placed in this field experiences forces that can be broken down into three primary vector components. These vectors arise from the interaction between the shifting magnetic field and the eddy currents induced within the disk.  The net effect on a very small disk is an orbital or spinning torque because the magnetic field is not just turning on and off; it is physically "sweeping" across the disk's surface.

1. The Axial Repulsive Force - This vector points away from the electromagnet’s face.  As the magnetic flux increases, it induces circular eddy currents in the small disk. According to Lenz's Law, these currents create a magnetic field that opposes the electromagnet.  For a small disk, this force is often weak enough that gravity or a pivot can overcome it, allowing the disk to stay near the pole face rather than being blown away.

2. The Lateral Drag Force - This vector points sideways, in the direction of the "sweep" (from the unshaded side toward the shaded/ringed side). The shifting magnetic field "drags" the induced eddy currents along with it.  If the disk is free to move, it will slide toward the copper ring. If it is pinned at its center, this lateral force becomes the Torque that makes it spin, as we see in the homopolar motor/generator.

3. The Radial Centering Force - This vector points toward the center of the highest flux density.  Because the copper ring delays the magnetic field, the "peak" of the field moves in a curve or gradient.  This is why we observe that a disk roughly the size of the ring gets "attracted" or trapped. The disk is essentially seeking the center of the shifting magnetic "hump".

Vector ComponentDirectionResulting Action
Axial (z-axis)Away from magnetRepulsion/Levitation (usually minor for small disks)
Tangential (0-axis)Unshaded ----> ShadedSpinning/Rotation
Radial (r-axis)Toward Ring CenterCentering/Attraction
   

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However, upon his request, you chose not to put the "gold dust" in the dust bin thread on the basis it was related to electron spin. My linking to the effects of rotating magnets is also related to electron spin. 
Not on that basis - only non-technical stuff goes into that dust bin.
If it smells like science or egineering, then it does not belong there.  That's why I replied to Smudge as I did about that special electromagnet that attracts non-ferromagentic materials.

Aside from the Einstein de Haas experiment, you have not made a convincing case linking the spin of an electron with the spin of a macroscopic object.  This will remain so even if you prove that the special electromagnet rotates small macroscopic conductive objects by classic induction (which you are on a good path to accomplishing).

It is an unavoidable conclusion that a shorted low-resistance loop creates a delayed magnetic field generated by a non-constant current.  This happens every day in shaded-pole motors and is happening in that special electromagnet, too.
Two phase-delayed magnetic fields are primed for creating a rotation.  You just have to rigorously show the two delayed perpendicular force components acting on a small conductive object.

Unless you prove the connection between these two spins, the discussion about that special electromagnet should be moved to its own thread but not to the dust bin ...even if it rotates macroscopic objects.
If you want to do this out of your own initiative then create a new thread and I will move the posts listed by you to that thread.

   

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No problem. It doesn't look like I am welcomed here.  I'll just go elsewhere.
I am sorry if I upset you, I was frustrated that you and others consider rotating fields when in my opinion there is no rotation.
However, Smudge wanted the effects of rotating magnets to be thrown in the dust bin as he did with the master magnet (gold dust).
That is not what I wanted.  I considered my input taking electro-magnets (either repulsing or attracting gold particles) into the realms of gold mining and prospecting was off topic.
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The spinning magnet setup is a classic demonstration of Larmor Precession and Orbital Magnetic Motion. The effects are primarily due to the magnet's intrinsic angular momentum (its physical spin) interacting with the external magnetic field.
Agreed, you are referring to the spinning PM where its magnetic axis is at an angle to the rotation axis thus creating precession.
Quote
The underlying physics is nearly identical for both the master magnet and the orbiting spinning magnet.
Here is where we disagree, the master magnet has no precession and I can’t see where field rotation occurs or applies.
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The conductive disk creates its own temporary "magnet" (via eddy currents)
Agreed
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which then tries to align with or "chase" the moving field of the electromagnet.
What moving field?  The electromagnetic field has time-changing magnitude, but what is moving?
 
Quote
In both cases, the asymmetry of the field (provided by the copper ring/larger magnet) converts a pulsating force into a continuous rotational torque.
Your two cases are comparing two different scenarios, a permanent magnet that has driven precession with an AC driven stationary electromagnet.  What is the evidence for the continuous rotational torque from the electromagnet? 
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The "Wobble" (Larmor Precession): When the small magnet spins, it gains angular momentum. The large magnet exerts a torque on the small one, trying to align its south pole with the large magnet's north pole. Instead of flipping instantly, the small magnet precesses (wobbles).  The specific combination of axial spin (counter-clockwise) and orbital rotation (clockwise) is a result of the Lorentz force and the conservation of angular momentum. The magnet "skates" along the isopotential because it is the path where its potential energy remains constant.  The fact that the axial spin and orbital rotation are in opposite directions is a macro-scale analogy to how orbital and spin angular momentum can couple in an atom. In quantum mechanics, this is known as Spin-Orbit Coupling. This experiment is a great classical analogy of the "effects" of electron spin
I understand all that where the driving device is a driven magnet precession.

Quote
The underlying physics is nearly identical for both the master magnet and the orbiting spinning magnet.  It's also nearly identical to the effects of rotating magnets that I linked to.  A smaller magnet spins because it's interacting with the changing field of a larger magnet. The conductive disk creates its own temporary "magnet" (via eddy currents) which then tries to align with or "chase" the moving field of the electromagnet. In all three cases, the asymmetry of the field (provided by the copper ring, or the larger magnet, or the rotating magnets) converts a pulsating force into a continuous rotational torque.
I do not see nearly identical physics, they are completely different.

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We have gradient-based eddy current forces in the master magnet. The relative size of the object changes the "net" force between repulsion (Lenz's Law)
Lenz’s Law applies to both repulsion and attraction of the conducting object.
 
Quote
and lateral dragging (the shifting field).
I don’t see a shifting field that drags anything.

Quote
We have three specific behaviors occurring, based on the size of the non-ferrous metal:

1. Large Object (Dominant Repulsion).
When the metal is larger than the copper ring, it intercepts a massive amount of the primary magnetic flux from the electromagnet.  The large surface area allows for massive, circulating eddy currents to form across the entire face of the metal.
This is clearly not correct.  The FEMM result shown in the video correctly shows the field emanating from master magnet through an annular gap at the outer edge of the copper ring.  That field cannot induce eddy currents over the entire face of the metal target.   
Quote
This results in an "opposing" magnetic field generated by the metal to be stronger than the localized "shifting" effect of the copper ring.
“Shifting” effect is hardly a scientific term.  What causes the shifting force?
Quote
The primary interaction is axial repulsion, it wants to push away from the magnet entirely.
Wrong, the video shows objects larger than the copper ring being attracted.

Quote
2. Matching Size (The "Trap" or Attraction).
When the metal is roughly the same size as the ring, it becomes "captured" by the localized field gradient created by the ring.  At this scale, the metal "sees" the difference between the unshaded and shaded poles clearly. The copper ring creates a region of lagging flux. As the magnetic field sweeps across the pole, the metal is constantly "chasing" the peak flux density.  This creates a centering force. Because the field is effectively "pulling" the metal toward the shaded portion and holding it there through the cycle, it appears to be attracted to the center of that ringed assembly rather than being blown away.
This is not a shaded pole motor, there are no shaded poles so this explanation is gibberish to me.  The induced eddy current does indeed turn the disc into an AC magnet that sits in an AC field.  Earlier you mentioned gradient-based eddy current forces and the direction of the axial force on the eddy current magnetic dipole depends on the direction of the gradient of the applied field.  It is the local field gradient that determines whether the force is attractive or repulsive. This is established physics that applies to both static fields and alternating fields.  The phase angle between the field waveform and the induced eddy current affects the instantaneous magnitude of the linear forces (radial and axial} on any part of the circular eddy current, it does not cause rotation.

Quote
3. Small Objects: (The "Motor" Effect).
When the metal is much smaller than the diameter of the ring, the field appears almost uniform across its small body, but with a high "phase gradient.
Wrong, the FEMM simulation clearly shows there is zero field at the centre and at that point there is no induced eddy currents, hence no force.  The video does show small objects attracted to and clinging to the annular gap through which the field emanates.
Quote
The small object acts like a tiny "squirrel cage" rotor. The magnetic field isn't just pushing it, it is rotating underneath it.  Because the object is small, the torque (turning force) becomes much more significant than the linear "push" or "pull".  The small piece begins to rotate or spin in place as it tries to synchronize with the sweeping field of the shaded pole.
Again, I obviously disagree and I see no evidence in the master magnet video of small objects rotating or spinning.

Smudge
   

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the floating magnet under the dremel driven magnet may be more like alternating field instead of rotating field.

back when i was at the electronics institute of Pittsburgh, one of the teachers was claiming that there were no electromagnets that could pick up copper, gold, silver, alum, etc

but in the old town im from, the library had many old books on electrics/electronics.  one of them had shown how to make an electromagnet that could do just that. it was alternating current driven. brought it in to show him and he stood corrected.

so maybe its not rotating mag field that suspends the magnet, but possibly alternating field.

Mags
   

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Scientists have recently discovered a doughnut-shaped structure within Earth's liquid outer core, parallel to the equator. This donut ring is a key player in generating earth's magnetic field.  An AC electromagnet with an annulus (donut ring) embedded in one end of the ferromagnetic core, will attract non-ferrous metals, such as gold, silver, copper, aluminum, etc. This is fascinating.


Que/Gravock
« Last Edit: 2026-04-19, 01:39:49 by Que »
   

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Not on that basis - only non-technical stuff goes into that dust bin.
If it smells like science or egineering, then it does not belong there.  That's why I replied to Smudge as I did about that special electromagnet that attracts non-ferromagentic materials.

Aside from the Einstein de Haas experiment, you have not made a convincing case linking the spin of an electron with the spin of a macroscopic object.  This will remain so even if you prove that the special electromagnet rotates small macroscopic conductive objects by classic induction (which you are on a good path to accomplishing).

It is an unavoidable conclusion that a shorted low-resistance loop creates a delayed magnetic field generated by a non-constant current.  This happens every day in shaded-pole motors and is happening in that special electromagnet, too.
Two phase-delayed magnetic fields are primed for creating a rotation.  You just have to rigorously show the two delayed perpendicular force components acting on a small conductive object.

Unless you prove the connection between these two spins, the discussion about that special electromagnet should be moved to its own thread but not to the dust bin ...even if it rotates macroscopic objects.
If you want to do this out of your own initiative then create a new thread and I will move the posts listed by you to that thread.

That's fair!  Thanks for clarifying your position and for your feedback.  I created a new topic here, https://www.overunityresearch.com/index.php?topic=4945.0 .  I'll send a list of posts to move to that thread.  Thanks for your feedback also Smudge. Much to learn from you, I will give you that.

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I am happy for all the gold magnet stuff to be moved into Que's new thread.  It will give me the opportunity to go into detail about my perception of why the devices in the videos work as they do, which will include the math, not just words.  That will go beyond the attraction of non-magnetic axisymmetric discs to the attraction of axisymmetric spheres as models for fine-gold small particles.

Smudge
   

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There is a cone-shaped area of attraction in the ac master magnet (see attached image).  Outside of this cone is a repulsive force. This allows us to create an ambipolar electric field, similar to earth's ambipolar electric field (video).  The ambipolar electric field is in two directions (second image).  The ambipolar electric field is what lifts and holds the atmosphere up.  This phenomenon, which counteracts gravity and ejects particles into space, has just recently been measured for the first time.

A plasma source, such as a Tesla globe, interacting with an ac master magnet will reproduce earth's magnetic field and ambipolar electric field.  We can place the ac master magnet in the space between a Helmholtz config.  The uniform magnetic field of the Helmholtz coil will significantly lower the Larmor frequency in the master magnet.  This allows us to use the Schumann Resonance frequency of 7.83 Hz as the slowed-down Larmor frequency in the AC master magnet.  By tuning the AC master magnet to a frequency of 7.83 Hz, we can create a magnetic field that resonates with the Earth's natural frequency.  The Larmor precession will cause the magnetic field to wobble. Earth's magnetic field has a wobble to it also. This can be used to simulate the Earth's magnetic field, ambipolar electric field, and study its interaction with the plasma in the setup.


Que/Gravock
 
   

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The approach I have described with the Helmholtz nulling field perfectly addresses the core challenge mentioned in Smudge's paper, the need for "extremely fast flux switching" to access hidden precession forces.  Smudge proposes that a "magnetic capacitor" effect occurs when you change a magnetic field faster than the quantum forces can adjust the precession frequency. By nullifying the static field, we've slowed that adjustment process (the relaxation time). The orthogonal coils can now "charge" this magnetic capacitor at much lower, more manageable frequencies (Hz or kHz instead of GHz).

Smudge suggests gaining access to precession energy via the spatially static longitudinal component rather than the rotating transverse one. This setup allows exactly this. The Helmholtz coils stabilize the longitudinal axis, while the orthogonal trigger coils provide the "instantaneous" change needed to disturb the dipole alignment.  His paper notes that if we can load the magnetic field (e.g., via the Search Coil) during the dipole's "relaxation time," we can extract energy directly from the "quantum engine" that is striving to restore the dipoles to their proper state. In the Earth Core model, this manifests as an amplified torque or a "boosted" vortex that appears to have more energy than the input signal provides.

In the "slow" larmor advantage we've lowered the Larmor frequency, and we no longer need the nanosecond rise times as mentioned in his paper on Page 3. The standard AC signal generator and orthogonal coils are now "fast enough" to "cheat Nature" and move the dipoles into the non-permitted states that Smudge theorizes will yield over-unity (OU) energy gains.

Smudge mentions on Page 13 that the "partially demagnetized" magnets or those with a lower Br might work better because they bring the resonance down to manageable frequencies.  The Helmholtz "bucking" method is a more precise, non-destructive way to achieve this same "conditioning" effect.

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Recently, researchers in the US have generated electricity from the Earth's rotation. Until now, this was thought to be impossible by physic laws. But the researchers have found a loophole, thanks to a special material, they were able to generate a small amount of electricity.

Que/Gravock
   

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Below is an AI rendition of the ac master magnet in the space between the Helmholtz config.  I described it, and the AI generated an image of the setup.

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I am happy for all the gold magnet stuff to be moved into Que's new thread.  It will give me the opportunity to go into detail about my perception of why the devices in the videos work as they do, which will include the math, not just words.  That will go beyond the attraction of non-magnetic axisymmetric discs to the attraction of axisymmetric spheres as models for fine-gold small particles.

Smudge

Tiny gold flakes and gold dust are not spherical as found in nature.  Why are you choosing to model the fine-gold particles as axissymmetric spheres, when that is rarely found in nature?

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Tiny gold flakes and gold dust are not spherical as found in nature.  Why are you choosing to model the fine-gold particles as axissymmetric spheres, when that is rarely found in nature?

Que/Gravock
Gold flakes are also not axissymetric discs.  But axissymmetric considerations allow us to derive useful math equations for the EM forces on them, both repusive and attractive.  That leads to a better understanding of how these "gold magnets" achieve their results which is much better than the somewhat contorted views presented by the makers of the various youtube videos on the subject.  The Lorentz motional force on an electric charge moving within a magnetic field is well known, but not one of those people explain how the circulatory moving electrons in the induced eddy currents obtain their attractive Lorentz force component that leads to the particle's attraction.   

Smudge
   

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Gold flakes are also not axissymetric discs.  But axissymmetric considerations allow us to derive useful math equations for the EM forces on them, both repusive and attractive.  That leads to a better understanding of how these "gold magnets" achieve their results which is much better than the somewhat contorted views presented by the makers of the various youtube videos on the subject.  The Lorentz motional force on an electric charge moving within a magnetic field is well known, but not one of those people explain how the circulatory moving electrons in the induced eddy currents obtain their attractive Lorentz force component that leads to the particle's attraction.   

Smudge

Dan Gilbert, an electrical engineer, describes how the circulatory moving electrons in the induced eddy currents obtain their attractive Lorentz force component that leads to the particle's attraction with an animation in this short video,  This is how I'm understanding it.


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The flux-preserving effect of that embedded copper or silver ring is very-short lived.  It decays with time.
This creates a delay between the preserved flux and the main alternating flux.

Perhaps Smudge could make several frames of magnetostatic FEMM sims where that embedded ring transitions from very diamagnetic to air-like as the current induced in it decays.
I can animate these frames.
   

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The flux-preserving effect of that embedded copper or silver ring is very-short lived.  It decays with time.
This creates a delay between the preserved flux and the main alternating flux.
I don't understand this preserved flux.  The copper ring has inductance and resistance, hence those values lead to a L/R time constant or relaxation time.  That effects leads to forces on the ring having a cyclic (averaging to zero force) component with a sin(2*wt) waveform at the driven frequency or having a "DC" component (force in one direction) with a sin2(wt) waveform.  But no "preserved" flux there, that remains cyclic.

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Dan Gilbert, an electrical engineer, describes how the circulatory moving electrons in the induced eddy currents obtain their attractive Lorentz force component that leads to the particle's attraction with an animation in this short video,  This is how I'm understanding it.


Que/Gravock

That is a different system to the copper ring/donut that I am writing about.  He clearly states two frequencies and I have to think about that before commenting.  The gold magnet videos that you and Verpies referenced use a single frequency.

Smudge
   

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That is a different system to the copper ring/donut that I am writing about.  He clearly states two frequencies and I have to think about that before commenting.  The gold magnet videos that you and Verpies referenced use a single frequency.

Smudge

Where does he clearly state two frequencies in that video?  I heard "two rotating fields", and not "two frequencies".  It's the same system that Verpies and I referenced.  It uses a single frequency and has a copper ring/donut in one end (see first and second images below).  As AllCanadian said, "In effect, it's a split shaded pole armature wrapped in a circle which is a brilliant concept".  Third image is Jeff Moe's ac master magnet.  Fourth image is from Cylo's Garage.  Cylo attended Dan Gilberts lecture and replicated the system using a ferromagnetic cylinder with an embedded copper ring in one end, as we find in Leonard Crow's article of the ac master magnet that AllCandadian referenced (fifth image).  In the 1951 publication by Leonard Crow, he also uses an E-core similiar to the method Dan Gilbert used (sixth image).  Same system, different methods of construction.

Que/Gravock
« Last Edit: 2026-04-21, 00:16:15 by Que »
   

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According to Crow in his 1951 publication on page 38, he states, "In order to use this type electromagnet for the attraction of small particles or pieces of non-ferrous metals, it is necessary that it be designed and constructed for operation on a supply of high frequency current.  The frequency required will depend on the size of the pieces or particles to be attracted".

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I don't understand this preserved flux.  The copper ring has inductance and resistance, hence those values lead to a L/R time constant or relaxation time. 
Yes, but because the ring is a shorted loop the current induced in it generates internal magnetic flux that opposes any changes to external flux that attempts to thread that loop.
Because of this opposition, during intervals which are much shorter than its L/R time constant, the magnetic flux threading the loop is effectively constant (frozen). 
If the loop were superconducting, its L/R constant would approach infinity and the magnetic flux threading that loop would remain constant forever, regardless of the changes to the flux external to that loop.  This is tantamount to freezing the threading flux because the flux threading an ideal shorted loop cannot change by definition.  ...but you already know all that.
   

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The master magnet was featured in Popular Electronics September 1962 publication on page 48 by Walter B Ford (PDF document attached).  A metal detector, the Lodestar, that is based on detecting eddy currents is mentioned in this publication.  The Lodestar, or a similar eddy current sensor, could trigger the master magnet when metal is detected.  The strength of the eddy currents would be a good indicator of the particle size,  which would tune the master magnet to a specific frequency for that particle size.

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Yes, but because the ring is a shorted loop the current induced in it generates internal magnetic flux that opposes any changes to external flux that attempts to thread that loop.
Because of this opposition, during intervals which are much shorter than its L/R time constant, the magnetic flux threading the loop is effectively constant (frozen). 
If the loop were superconducting, its L/R constant would approach infinity and the magnetic flux threading that loop would remain constant forever, regardless of the changes to the flux external to that loop.  This is tantamount to freezing the threading flux because the flux threading an ideal shorted loop cannot change by definition.  ...but you already know all that.
But that "remaining for ever" is a zero value, the superconducting loop carries current to ensure that situation.  That current creates a magnetic field outside the loop which we are interested in as it sums with the AC applied field.  We don't get a "remaining for ever" current, and we get a modified AC field pattern external to the loop that accounts for the attraction and repulsion zones.  Note that unlike bulk superconducting material the donut shape allows closed field lines within the hole in the donut while meeting the condition of zero flux threading the loop.

Smudge
   
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