Discussion about Lenz law

[Farmhand]

Well here is a definition from Encyclopedia Britannica.

Lenz's Law definition.

Lenz’s law, in electromagnetism, statement that an induced electric current flows in a direction such that the current opposes the change that induced it. This law was deduced in 1834 by the Russian physicist Heinrich Friedrich Emil Lenz (1804–65).

Lenz's law (physics) -- Britannica Online Encyclopedia

Originally Posted by Boguslaw
I still do not understand. I believe magnetic field has always two poles,right ? So you are stating that when I take a large magnet and move it's N pole to the wire, the current generated inside wire will create magnetic field of what polarity ? North ? South ? and where is the opposite pole created ?

From the page.

Thrusting a pole of a permanent bar magnet through a coil of wire, for example, induces an electric current in the coil; the current in turn sets up a magnetic field around the coil, making it a magnet. Lenz’s law indicates the direction of the induced current. Because like magnetic poles repel each other, Lenz’s law states that when the north pole of the bar magnet is approaching the coil, the induced current flows in such a way as to make the side of the coil nearest the pole of the bar magnet itself a north pole to oppose the approaching bar magnet. Upon withdrawing the bar magnet from the coil, the induced current reverses itself, and the near side of the coil becomes a south pole to produce an attracting force on the receding bar magnet.

A small amount of work, therefore, is done in pushing the magnet into the coil and in pulling it out against the magnetic effect of the induced current. The small amount of energy represented by this work manifests itself as a slight heating effect, the result of the induced current encountering resistance in the material of the coil. Lenz’s law upholds the general principle of the conservation of energy. If the current were induced in the opposite direction, its action would spontaneously draw the bar magnet into the coil in addition to the heating effect, which would violate conservation of energy.

Collapse what ? Why magnetic field do not just vanish immediately in no time ? Looks like it has a supporting "thing" inside wire ?

I think because the magnetic field has energy concentrated in it and this
energy has to dissipate, it cannot just disappear.

I think the old explanation of the inductor trying to maintain current flow is
not really entirely accurate, in my opinion because of the energy of the
magnetic field having to dissipate due to not having a current to support it's
continuation, when the current that makes it is stopped then the energy simply
looks for the easiest way to dissipate and takes the path the original current
took if it can if not it will take the next best path or just oscillate the coil
until dissipated.

I don't think it's a matter of the inductor wanting to keep the current flowing,
I think it's a matter of it's the energy of the magnetic field's best or only way
to dissipate. Effect is the same so not important.

For the simple definition of Lenz's Law to be shown as not always correct I
think an induced current would need to be caused which aids the change that caused it.

I don't think that simply showing a generator rotor accelerating under load or
a transformer's reduction in input power when loaded shows any Lenz violation,
I think it shows something else as the cause, probably more than one other reason.

Cheers

P.S. I think Lenz's Law defines the effect of the transfer of energy by induction, more
energy transferred equals more Lenz effect, Less Lenz effect equals less
energy transferred. All my experiments point to this being true.

..

[level]

...
I think the old explanation of the inductor trying to maintain current flow is
not really entirely accurate, in my opinion because of the energy of the
magnetic field having to dissipate due to not having a current to support it's
continuation, when the current that makes it is stopped then the energy simply
looks for the easiest way to dissipate and takes the path the original current
took if it can if not it will take the next best path or just oscillate the coil
until dissipated.
I don't think it's a matter of the inductor wanting to keep the current flowing,
I think it's a matter of it's the energy of the magnetic field's best or only way
to dissipate. Effect is the same so not important.

Hi farmhand. Yes, the expression of an inductor 'wanting' to oppose changes to its current is just an expression of convenience. I don't think it was/is ever meant literally. It gets the point across nicely however. As I mentioned before, an inductor acts in such a way as to always try to oppose external actions that cause changes to its current, but again here, there is also really no 'trying'. What Lenz described is the basic inherent properties of an inductor. These are the properties that make an inductor act like an inductor. These properties exist due to the self induction that occurs in an inductor. If you don't have those properties, then you don't have an inductor. You will have something else.

Basically what Lenz described is that there is a very definite relationship between an externally applied voltage or magnetic field, and the resulting induced voltage, current, and resulting induced magnetic field in an inductor. This relationship can be very simply summarized as an inductor always acts in such a way as to try to oppose an external action that is causing changes to its current. The actual mechanics of why this works this way is not really critical to understanding Lenz's law. Lenz just pointed out the properties and relationship. The actual mechanics of it all are left to others, although Lenz may have delved into that aspect as well.

[Ein~+ein]

I agreed with what Garrett orignally wrote:

Lenz's Electrical Observations = Newton's Mechanical Observations

If BEMF = electrical inertia it would explain why expelling magnetic fields through super-cooling is the way to achieve superconductivity. On that note, Dave45 ought to try submerging his coils in dry ice.

I'm no expert but would the next step in IC chip miniaturization be nano-3D printing (molecule-by-molecule) of conductive material to reduce heat and EMF radiation?

[garrettm4]

If BEMF = electrical inertia it would explain why expelling magnetic fields through super-cooling is the way to achieve superconductivity. On that note, Dave45 ought to try submerging his coils in dry ice.

I'm no expert but would the next step in IC chip miniaturization be nano-3D printing (molecule-by-molecule) of conductive material to reduce heat and EMF radiation?

Ein~+ein,

Thanks for your support.

Now this might sound like I'm beating you up, but I would have to say that you are way off in left field on the affect of absolute temperature and its relation to magnetism!

Back EMF has nothing to do with super conductivity! As BEMF is the affect of an expanding magnetic field in an inductor during CHARGING. That is, an inductor OPPOSES the change in current through it. This opposition is seen as a VOLTAGE across the inductor opposite to the direction of the applied voltage. Hence the term "Back EMF". Sometimes called an inductive voltage drop, which is very much like a resistive voltage drop. Now, when talking about motors the BEMF is more complex so I won't get into that topic here. The contraction of a magnetic field, during discharge, produces an EMF in the same direction as the initial power source. That is, they are both in series, or are additive. This could be called the Forward EMF, as it IS NOT a drop in potential, but instead a rise in potential. Confusing indeed. And even more so when you examine the picture with sinusoidal AC. As the change in magnetism is proportional with the current through the inductor (rising and falling and reversing etc.) the forward emf of the contracting magnetic field ends up in reverse direction to the applied AC source, thus you end up adding two quadrature sine waves together to form a third effective one measured in the circuit. With pulsed DC, the BEMF is seen during charging as a drop in applied potential across the reactor (reactor voltage drop - source voltage). The FEMF is seen during discharge as a rise in potential in series with the source (reactor voltage + source voltage). The pulsed or transient conditions of inductor circuits follow a logarithmic envelope related to epsilon or Napier's constant. This being related to the time constant, tau, expressed as: tau (in seconds) = L (henries) * r (ohms). There being 5 practical time constants in the envelope. Sinusoidal circuits of a continuous condition have a flat (unchanging) envelope, however "dampened AC waves" also follow the logarithmic progression of epsilon.

Super conductors are affected by ANY magnetic field, they make no distinction between an EMF vs. a BEMF. Therefore, any external magnetic field will cause induced surface currents that then perform screening of the external field by a reverse field from the surface currents. The term super conductivity is derived at by the observation of the lifetime of the induced surface currents. That is, they don't decay due to resistive losses, and hence demonstrate that there is zero resistance or "super conductivity"

Finally, "radiation" is related to a lot more than "EMF". As you have near-fields AND far-fields, your "EMF" would represent a time variant electrostatic near-field. Further, EM radiation is determined by the antenna structure (intentional or not), and its radiation resistance.

Once again, I'm not trying to beat you up, just pointing out how I see things.

Garrett

[Ruphus]

there's a spike. When you break it there's a spike. Connect it and break at the same time,same time.

This I believe is what is happening here. Its very interesting!

Angus Effect

A search on the topic brought up nothing so I'll place it here.

[Ein~+ein]

...you are way off in left field...

Still trying to appreciate how and why this works. Thanks for helping.

[boguslaw]

Here are my thoughts loosely related to Lenz law. I learnt that Lenz law is about transients or changes but it didn't explain their nature or the basis. Is that because of changing EMF which cause changing magnetic field or is that about changing magnetic field which cause counter-EMF ?

Ok, you probably saw that example before.... take two coils of the same resistance but different number of turns connected each one to own DC power supply giving the same finite max power. Now ,as I understand the Lenz law occur when we turn power switch and the current start to flow. In the circuit with coil of larger inductance (more turns) , time required for reaching max power is longer then in circuit with coil of less turns.
When the max power is flowing in both of circuits there is no difference between them except when you turn the power switch off.... the flyback is higher voltage in circuit with more inductance.
Contrary to some videos I think there is no direct gain here because the longer time required to reach max power, the energy expended initially is more in case of large inductance to overcome Lenz law.
Is that correct ? MY intuition tells me that if my theory is correct , I can explain it by more wire mass containing more electrons to align during initial power on time. Sure, it may not add any significance to the Lenz law usage in this case but hold on.....maybe we can find some....

In this simple experiment IMHO we separated in time action (initial Lenz law opposition to current flow) and rection - collapsing magnetic field flyback, and it's a quite a benefit for us.

Here I can already propose one of OU design - after separating in time action and reaction we should simply find a way to temporarily nullify inductance however high it can be during the initial period of "charging coil"..... and we know it's possible..... in resonance...

It's a one way for OU

[Bob Smith]

Boguslaw, what do you think of this setup in light of your March 30th comments?
PERPETUAL MOBILE - BITOROID TRANSFORMER - YouTube
Bob

[boguslaw]

Boguslaw, what do you think of this setup in light of your March 30th comments?
PERPETUAL MOBILE - BITOROID TRANSFORMER - YouTube
Bob

It should work but definitely not as presented, unless there is a radio transmitter nearby.
Sorry, I'm a bit busy these days....

[shylo]

connection

The Angus Effect, very interesting,thx Ruphus.
When you create a flow,that opposite reaction shows up,but..before it does for that instance....catch it.
shylo

[Ruphus]

I thought it was VERY interesting!! That guy was reproducing the effect from Anguswangus. It's like using Lenz Law in reverse, or using eddy currents to power the secondary circuit which may flip the magnetic eddy current of the pickup and help drive the rotor.

I'm hoping he puts magnets all the way around the rotor and just uses one pickup. Or I might have to build it myself just to see what happens

[kEhYo77]

And here is an experiment of J.L. Naudin confirming phase shift in a laminated transformer core.
Solid State Delayed Lenz Effect in laminated steel core proved with the VRM measurement
You can see him probing the induced magnetic field around the core with a Hall sensor. The shift happens at some distance from the oscillating coil.
This confirms the method used by Tesla to achieve a second phase in one of his 4-pole AC motor, having only one AC input signal.
It is achieved by moving 2 stator coils further back on their cores, away from the rotor.

So, to build a delayed Lenz generator coil we need only a long core protruding from the front of the coil.
... just as Anguswangus did with his PMH gen coils.

[Farmhand]

I posted about this motor before in the Romero/Muller thread.

Patent US524426 - NIKOLA TESLA - Google Patents

It must work because Tesla would have tested it.

Cheers

Edit.

P.S. I think this is the motor kEhYo77 refers to in above post.

Quote:
This confirms the method used by Tesla to achieve a second phase in one of his 4-pole AC motor, having only one AC input signal.
It is achieved by moving 2 stator coils further back on their cores, away from the rotor.
I think it's a delay in the magnetization of the core along it's length away
from the coil.

I think it's just a delay in the magnetization of the core away from the coil.


...

[Ruphus]

Not Sine and Cosine as I hoped! But sin(x) and -sin(x) will be likely be more useful. Thanks for the link kehyo77!!!!

[Allcanadian]

@kehyo77

And here is an experiment of J.L. Naudin confirming phase shift in a laminated transformer core.
Solid State Delayed Lenz Effect in laminated steel core proved with the VRM measurement
You can see him probing the induced magnetic field around the core with a Hall sensor. The shift happens at some distance from the oscillating coil.
This confirms the method used by Tesla to achieve a second phase in one of his 4-pole AC motor, having only one AC input signal.
It is achieved by moving 2 stator coils further back on their cores, away from the rotor.

I mean no offense but I had to laugh when I saw this video and it is a good example of what can happen when people fail to learn the basic principals of electrodynamics.

Now watch the video again and notice how the polarity reverses after the center of the laminated core. This happens because the magnetic field of the coil has induced a magnetic field in the laminated core. It is called "magnetic induction" and has been know for a very long time.

When a magnet approaches an iron core it induces (magnetic induction) a magnetic field of opposite polarity in the core and this is the sole reason why the magnet is attracted to the iron core. We should be clear that a magnet is not attracted to iron as it does not have this capacity, the field of the magnet is attracted to the field induced in the iron core. Only fields have the capacity to act through a distance on one another.

As well notice how at the left we have one polarity, at the center no polarity and on the right an opposite polarity indicated by the hall probe just like a real magnet because it is one in this case. The point of no polarity is called the neutral center and is found in every magnet and every magnetic field. This is the singular point where one field diverges into two opposite polarities however we should understand the field in itself is two manifestations of one thing... magnetism.

I always use Hall Effect Probes to measure magnetic field density however not unlike an oscilloscope these tools are only as good as the operator. We have to know what it is we are actually seeing or measuring and how it relates to what is happening.

AC