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Author Topic: Using natural (thermally driven) remanence decay to deliver overunity energy  (Read 10712 times)
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Don't loopstick antennas work well? They are just strands of Litz wire wrapped around a ferrite core (usually MnZn), that are effective up to 5MHz-ish.

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To understand what MnZn Ferrites are or what that acronym means, one must first have a basic idea of what ferrites are. Simply put, ferrites are ceramic materials that are a mix of iron oxide, zinc, nickel, manganese and other compounds. Their ability to retain spontaneous magnetisation allows usage in a wide variety of applications.

Ferrites are predominantly divided into Hard & Soft Ferrites.

    - Hard Ferrites are tough to magnetise because of their high coercivity, making them ideal to use in appliances like refrigerators, washing machines, and televisions.
    - Soft Ferrites have a decent ability to conduct magnetic fields which is useful for developing transformer cores and also in electrical & medical devices.

What are MnZn Ferrites?

Soft ferrites further branch out to others, the most common ones being MnZn (Manganese-Zinc) & NiZn (Nickel-Zinc) ferrites. MnZn ferrites are a type of soft ferrite that carry good electrical & magnetic properties.

They are often preferred over NiZn ferrites because of their higher permeability, magnetisation ability & lower value of resistivity as compared to its counterpart. MnZn ferrites are also low in cost & power losses with high values of magnetic induction that are desirable by power applications, sensors, biomedical applications, inductors etc. Most of their applications rely on their properties of stress insensitivity & adequate working under 2 Mhz.

Useful Traits

One can notice multiple benefits of using the MnZn ferrites. Among all these, a few stand out that are often the deciding factor in using these ferrites.

Low Power Loss

Unnecessary power losses can vastly affect the performance of applications that work on constant power. Loss because of hysteresis is an example of this power loss. It happens during the magnetization and demagnetisation of the ferrite and is lost to the environment as heat. These losses build up with continuous use.

MnZn cores keep power losses because of such effects as low as possible, allowing the efficient working of electronic applications.

Low Remanent Magnetisation

Soft ferrites aren’t permanent magnets but they don’t lose magnetisation completely either. In the absence of a magnetic field, their magnetism decreases. In such cases, there is a residue value known as remanent magnetisation.

MnZn ferrites show an increase in value before decreasing and hence offer a low value of remanent magnetisation.

Low Coercivity

The coercivity of any material is its ability to withstand demagnetisation in an external magnetic field.

MnZn ferrites have low coercivity which means it has low resistance to any change in their magnetisation. This property lets them be readily used in applications where polarity will be often reversed.
   

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Whatever the means of obtaining magnetization, the magnetic energy density is W=B²/2.µ. This energy will have to be supplied for magnetization (plus losses) and it doesn't matter which means is used, be it electrical, mechanical by influence, or anything else.
In that W=B²/2.µ formula when related to the B within ferromagnetic material the permeability µ contains the relative permeability of the material.  For soft material with a perfect linear B v. H (that doesn't really exist) there is no problem with that formula and it is easily shown that this energy density exacty agrees with the area of the BH loop triangle both for magnetization and demagnetization.  Electrical energy out = electrical energy in.  When it comes to real materials the relative permeability is not a constant, it depends on the H history leading to hysteresis.  So what µ should we use in that formula?  For square-loop material that has been magnetized (a permanent magnet) what µ would you use?  The known incremental µ is µ0 and if you use this value you get the energy density of the known B value of the magnet in air or free-space, the very thing that you say is inaccessible.
   
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It's therefore essential that you define the "something" you're talking about, and not from the formalism of the laws of physics, since they guarantee the conservation of energy through their internal mathematical consistency.
In an AC transformer we have the core being demagnetized over part of a cycle inducing voltage ino a coil driving current into a load resistor yielding energy far in excess of that supplied for the magnetization.  In that case the "something" supplying that energy is the voltage.current in the primary coil. 
For the system being discussed in this thread the "something" is the thermal input KT (K is Boltzmann's constant and T is absolute temperature) that appears in the Neel formula for the remanent magnetism relaxation time (decay time constant).  When we use that non-electrically-driven decay we are not extracting the so-called magnetic energy stored in the core, we are extracting it from the effects of the thermal agitation.  Yes the loss of magnetic energy needs replenishing and that is taken into consideration.  We have to resupply that energy including losses just as we do in the normal transformer.   

Smudge 
   
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...When it comes to real materials the relative permeability is not a constant, it depends on the H history leading to hysteresis.  So what µ should we use in that formula?  For square-loop material that has been magnetized (a permanent magnet) what µ would you use?

We're talking about µ at the moment we apply the calculation. The relationships between B(t) and µ(t) are true at every instant, including that of magnetic energy density.
When µ varies, it's because the energy is distributed differently. For example, some of it may be lost through its work on realigning the magnetic domains at the same time as µ is reduced.
Whether the variation is in time or in space (e.g. a ferrite used as a transmission line), the equations apply step by step, in time or in space.
If we remain on a macroscopic scale and see only the whole, we can't draw any conclusions. If µ varies, we need to look step by step in time and space to see where the energy is going and in what form.

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In an AC transformer we have the core being demagnetized over part of a cycle inducing voltage ino a coil driving current into a load resistor yielding energy far in excess of that supplied for the magnetization.  In that case the "something" supplying that energy is the voltage.current in the primary coil.

I don't agree with this way of presenting the facts. That the magnetic energy of a transformer is constantly fed by the primary current and constantly consumed by the secondary current is nothing new. The quasi-concomitance of the two gives the illusion that the transformer doesn't store the energy passed from one to the other, but this is not true. There is a delay during which the energy is stored in magnetic form in the transformer core, during this very short transfer time. The principle is the same as if energy were passed through a capacitor alternately switched from input to output.

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For the system being discussed in this thread the "something" is the thermal input KT (K is Boltzmann's constant and T is absolute temperature) that appears in the Neel formula for the remanent magnetism relaxation time (decay time constant).  When we use that non-electrically-driven decay we are not extracting the so-called magnetic energy stored in the core, we are extracting it from the effects of the thermal agitation.  Yes the loss of magnetic energy needs replenishing and that is taken into consideration.  We have to resupply that energy including losses just as we do in the normal transformer.   

Smudge

Heat is one of the forms in which magnetic energy can transform when µ or any other parameter changes, and it's one of the changes of form I mentioned in paragraph 1. I fully agree that this transformation can be achieved by supplying energy. But if you agree that "the loss of magnetic energy needs replenishing", that's the crucial point. If you can't replenish this energy at a lower cost, the device remains completely conventional, and I can't see any reason why it shouldn't be.


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We're talking about µ at the moment we apply the calculation. The relationships between B(t) and µ(t) are true at every instant, including that of magnetic energy density.
When µ varies, it's because the energy is distributed differently. For example, some of it may be lost through its work on realigning the magnetic domains at the same time as µ is reduced.
Whether the variation is in time or in space (e.g. a ferrite used as a transmission line), the equations apply step by step, in time or in space.
If we remain on a macroscopic scale and see only the whole, we can't draw any conclusions. If µ varies, we need to look step by step in time and space to see where the energy is going and in what form.
You have dodged the question I posed and introduced your own personal perception of magnetism.

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I don't agree with this way of presenting the facts. That the magnetic energy of a transformer is constantly fed by the primary current and constantly consumed by the secondary current is nothing new. The quasi-concomitance of the two gives the illusion that the transformer doesn't store the energy passed from one to the other, but this is not true. There is a delay during which the energy is stored in magnetic form in the transformer core, during this very short transfer time. The principle is the same as if energy were passed through a capacitor alternately switched from input to output.
You clearly have a different perception of the principles of transformer action than I do.  I am 90 years old and have been immersed in EM theory since the age of 16; in all those years I have never come across what you present here and with which I violently disagree.  Show me some proof.

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Heat is one of the forms in which magnetic energy can transform when µ or any other parameter changes, and it's one of the changes of form I mentioned in paragraph 1. I fully agree that this transformation can be achieved by supplying energy. But if you agree that "the loss of magnetic energy needs replenishing", that's the crucial point. If you can't replenish this energy at a lower cost, the device remains completely conventional, and I can't see any reason why it shouldn't be.
Of course you can't because you have this (IMO incorrect) perception of energy transfer.

Smudge
   

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Of course you can't because you have this (IMO incorrect) perception of energy transfer.


If you think that you can or cannot, you are right in any case. (Henry Ford). :)
   
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You have dodged the question I posed and introduced your own personal perception of magnetism.
You clearly have a different perception of the principles of transformer action than I do.  I am 90 years old and have been immersed in EM theory since the age of 16; in all those years I have never come across what you present here and with which I violently disagree.  Show me some proof.
Of course you can't because you have this (IMO incorrect) perception of energy transfer.

Smudge

Hey Smudge. It seems people always ignore the importance of the all important aspects of hysteresis, time and time again. Everything has to be linear. I find it comedic really.

Heres a good reminder:
https://www.youtube.com/watch?v=GiG0e1s6nV4

When you introduce "memory" you are breaking symmetries in time and energy starts to flow, one way or the other. Whether its "free" is a whole different debate. Rubber, Nitinol, Iron...all have a hysteresis. But hey we are all just crackpots here what do I know.

   

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That the magnetic energy of a transformer is constantly fed by the primary current and constantly consumed by the secondary current is nothing new. The quasi-concomitance of the two gives the illusion that the transformer doesn't store the energy passed from one to the other, but this is not true. There is a delay during which the energy is stored in magnetic form in the transformer core, during this very short transfer time. The principle is the same as if energy were passed through a capacitor alternately switched from input to output.

Since transformers transfer power any quantity of energy involves time.  You mention a short transfer time that is negligible compared to the time taken by the system to traverse its B v. H (or Flux v. Current) loop.   The peak magnetic energy in the core (accumulated over time like a half cycle and is recycled anyway) is related to the peak energy transferred from input to output by the core’s permeability, the higher the permeability the smaller that core energy.  In a loaded AC transformer, the energy per half cycle appearing in the load resistor is far greater than the core magnetic energy associated with the changing field.

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Heat is one of the forms in which magnetic energy can transform when µ or any other parameter changes, and it's one of the changes of form I mentioned in paragraph 1. I fully agree that this transformation can be achieved by supplying energy. But if you agree that "the loss of magnetic energy needs replenishing", that's the crucial point. If you can't replenish this energy at a lower cost, the device remains completely conventional, and I can't see any reason why it shouldn't be.

The device is not conventional because it has not been done this way before.  The nearest is charge and discharge of an inductor where input and output occur at separate times and the magnetic energy stored in the core equals both input and output energy.  But this new system is not charge and discharge of an inductor.  It is charge of a “permanent magnet” over one time span followed by another time span during which the “permanent” magnetic field is driven down to zero by some “external means”.  The energy taken from that external source appears in our load resistor.  In a loaded AC transformer, as we lower the resistance value the energy transfer increases while the field change and core energy remains the same.  The primary source supplies both energies.  In this new system the “external means” acts like a primary to supply the output energy and the field change (decay), as we lower the load resistor value we extract more energy for the same field change.

Smudge
   
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I came across this interesting piece by Harold Aspden which seemed relevant to the topic.

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The curious fact that our thermoelectric refrigeration device is built with an inherent functional symmetry and yet it always cools on its exposed test heat sink surface, it being noted that the electrical operating unit is mounted on the same panel that constitutes the second heat sink surface. The latter gets hot as the former cools, but, unless Scott Strachan builds a version that separates the electrical operating unit from the second heat sink we shall have to await the clear experimental evidence that, in truth, both surfaces are cooling as the device delivers electrical power!

The idea that one can build a power transformer which draws in heat and so cools a housing in which it is enclosed and at the same time converts that rejected heat into electricity fed along wires leading from that housing is one that seems beyond belief. It defies the second law of thermodynamics, but that should not deter a pioneer who has in his possession the device mentioned above.

The object of the experiment is to test a suspicion that current circulation within a bimetallic lamination can, under certain circumstances, result in cooling for current flow across the thickness of the lamination. The experiment acknowledges that such cooling would produce an EMF and put electrical power into increasing the current flow in the plane of the lamination, unless deflected from the lamination, transverse to its width. This means extra heating and anomalous loss augmenting the eddy-current loss, but such an anomaly is direct evidence of that underlying cooling and electrical generation.

The prototype devices all used thin film bimetallic layers of aluminium and nickel and involved that transverse 'deflection'. The 'circumstances' stated are that the lamination includes a ferromagnetic layer of thickness less than the 100 micron dimension, the size of a magnetic domain formed within the larger crystals of the material.

In the subject experiment, there was no transverse deflection but the other condition was met. Commercially available steel foil (known in the trade as 'shim steel') of 2 thousandths of an inch in thickness was obtained and an electroplating firm was asked to coat one face with nickel using an electroless plating process. The nickel coating was 0.7 thousandths of an inch in thickness. It was found that this could be cut into small rectangles for assembly in a 100 VA transformer core, supplied in kit form (eg. R.S. Components in U.K.). Thin card placed between the laminations was used to insulate them from each other. The arrangement was as shown in Fig. 10, with legs A and B being formed by the bimetallic pieces. Primary and secondary windings, respectively series-connected in pairs, were formed on each of the legs A and B.

The test involved observing on an oscilloscope the changing shape of the B-H magnetization loop as primary current input increased.

To present the B-H loop on an oscilloscope screen the secondary winding was connected across a 100k resistor in series with a 2 µF capacitor and the Y input to the oscilloscope was taken across the capacitor terminals. The H input was provided by incorporating a series resistor in the primary feed circuit and taking the X input from the potential drop across that resistor.

What I was intending by this experiment was to estimate the eddy-current loss resulting from the bimetallic lamination feature. Having done Ph.D. research studying anomalous eddy-current losses experimentally I was particularly curious as I had never heard of anyone ever before testing a transformer built using bimetallic Fe:Ni laminations. Moreover I knew that I was using laminations that were much thinner, though more conductive, than is customary in transformers.

Added to this, I knew from my Ph.D. research days, during which I measured the loss factors in different elemental sectors of the B-H loop, that there was a particularly high and inexplicable loss in a part of the loop where it was least to be expected.
   
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That the magnetic energy of a transformer is constantly fed by the primary current and constantly consumed by the secondary current is nothing new.

First we need to be clear that nothing is "consumed". Energy cannot be created or destroyed only transformed. Energy is transferred from the primary to the secondary by way of a changing magnetic field. I say "magnetic field" as a generalization but it should be understood the field is made of billions of smaller magnetic fields relating to the atoms which make up the conducting and magnetic material.

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The quasi-concomitance of the two gives the illusion that the transformer doesn't store the energy passed from one to the other, but this is not true. There is a delay during which the energy is stored in magnetic form in the transformer core, during this very short transfer time. The principle is the same as if energy were passed through a capacitor alternately switched from input to output.

I would agree to some extent. I needed to know the actual facts of the matter so I started placing and embedding hall effect sensor arrays in and on inductors and transformers. As you say there is always a slight delay but I found there is much more to it. You see most don't seem to understand the how and why of the actual mechanism driving the energy transfer. In reality the secondary of a transformer acts almost identical to a shaded pole. That is, the primary current starts producing an expanding magnetic field which induces the secondary. The induced secondary then produces it's own current and secondary magnetic field. The secondary magnetic field then opposes the primary magnetic field which induced it in the first place. We can measure the extent of field opposition as a local increase in the magnetic field density and a shift in field polarity.

So in fact the induction process looks more like this...
Primary current, delay, primary magnetic field expanding, delay, secondary current induced, delay, secondary magnetic field expanding, delay, secondary field opposes the primary field, delay, increase of field density at primary/secondary transition point. Ergo, it is not one delay but many during each step of the induction process.

I would also note my experiments were made on transformers having separate primary and secondary windings. If a primary is wound over the secondary or vice versa it is nearly impossible to track the field changes.

AC





« Last Edit: 2024-07-03, 23:25:57 by Allcanadian »


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“The first principle is that you must not fool yourself and you are the easiest person to fool.”― Richard P. Feynman
   

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For those who insist that the energy obtained from this remanence decay cannot exceed the energy required to re-magnetize the core consider the following experiment.  We have at our disposal a thin rod of our square-loop material that is pre-magnetized.  It is now a permanent magnet, but one that can easily have its polarity switched by bringing it close to a more powerful PM.  Energy is consumed in this process that is supplied from two sources.  One source is the force needed to push the magnets together in repelling mode.  Another is the energy supplied during the polarity flipping that occurrs suddenly, and is taken from the powerful PM, it gets some small loss of its magnetization.  Depending on the shape of this powerful PM our thin rod might not get all its atomic dipoles flipped, and the same goes for dipoles in the PM.  This will leave stresses in the materials that can eventually cause them to break apart.  (I have had a NdFeB disc magnet fall apart after switching the polarity of a number of caramic magnets).  Assume we use a horseshoe PM to get the entire rod material to flip.  Then we adjust our experiment to stop the PM movement at the point where only half the dipoles have flipped, where our material is now demagnetized (very difficult to achieve but this is only a gedanken experiment).  Now we can pull the PM away at no energy cost as there is zero force.  We then remagnetize our material by passing current through a coil wound on it.  We also make up the small loss of magnetization in our PM.  An energy audit will tell us that we have supplied a fixed amount of electrical energy related to the demagnetization and remagnetization.  We can repeat this process at some rep rate and our experiment continually consumes power.

Next we arrange for the coil around our material to be connected to a load resistor only during the demagnetizing phase of the movement.  By Lenz's Law the current creates a field that opposes the demagnetizing field, there is greater opposing force on the moving PM.  We get energy out in the load resistor that is exactly accounted for by the extra repulsion force hence extra input energy during the movement.  The remagnetization input energies remain the same.  As we lower the value of the load resistor we get more and more energy there but fully accountable by input energy during movement.  The system is always less than 100% efficient when losses are taken into account, but electrical energy into the load can be many times the electrical energy needed for remagnetization.  If we just consider only those input/output electrical energies we would get significant OU because we have not included the PM movement energy as a source.  My remanent magnetization decay calculations are giving me significant OU because I have not included the source of that decay in the energy calculations.

Smudge         
   

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So in your gedanken experiment the demagnetization is caused by the work performed by the PM (a movement against the repulsive force).
...and in the proper experiment the demagnetization is caused by the heat.

Doesn't the magnetocaloric effect heat up the rod during its magnetization ?
Why isn't this magnetization immediately destroyed by the same heat when the magnetizing field is removed ?
   

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So in your gedanken experiment the demagnetization is caused by the work performed by the PM (a movement against the repulsive force).
...and in the proper experiment the demagnetization is caused by the heat.
Yes, and the repulsion force is enhanced by the load current so more work that accounts for the load energy.

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Doesn't the magnetocaloric effect increase the heat of the rod during its magnetization ?
Yes
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Why isn't the magnetization of the rod immediately destroyed by the same heat when the magnetizing influence is removed ?
A small increase in heat does not suddenly destroy, the Neel equation tells us it reduces the relaxation time.  Also the extraction of energy from the heat bath into our load must reduce the heat thus compensating for that increase.

Smudge
   

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Don't you think that Gadolinium would be easier to keep around the Curie temp than the ferrous materials ?

...cheaper too, if you account for the cost of the high temp kiln and keeping the copper turns insulated at high temperatures while keeping them from oxidizing and copper's increased resistivity at these temperatures.

https://www.ebay.com/itm/232962852067
   

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@Verpies,
It has relative permeability only in the low tens which is why I did not consider it.  If it was available in the right form for a core (long thin or ring shape) it would be worth doing an experiment.

Smudge
   

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It has relative permeability only in the low tens which is why I did not consider it.
It is not so bad when it is cooled.
According to the graphs below, Gadolinium's maximum permeability is achieved in the Dry Ice regime ...which is cheap and easy to work with (...well, easier than with LN and LH and with burning wire insulation and copper's oxidation at 770ºC).



Do the ferrous materials maintain their high permeability up to their Curie temp (TC) ?

If it was available in the right form for a core (long thin or ring shape) it would be worth doing an experiment.

It is:
https://www.ebay.com/itm/383881065303
   

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It is not so bad when it is cooled.
According to the graphs below, Gadolinium's maximum permeability is achieved in the Dry Ice regime ...which is cheap and easy to work with (...well, easier than with LN and LH and with burning wire insulation and copper's oxidation at 770ºC).
That data is interesting.  What we also need is relaxation time against temperature, where can we find this?

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Do the ferrous materials maintain their high permeability up to their Curie temp (TC) ?
I don't know, how do we find that data?
[/quote]
   
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