Lens's Law what is it ?

[Farmhand]

I found this on this page. Source of definition. LINK

Text made bold by me.

"Lenz's law

A law of electromagnetism which states that, whenever there is an induced electromotive force (emf) in a conductor, it is always in such a direction that the current it would produce would oppose the change which causes the induced emf. If the change is the motion of a conductor through a magnetic field, the induced current must be in such a direction as to produce a force opposing the motion. If the change causing the emf is a change of flux threading a coil, the induced current must produce a flux in such a direction as to oppose the change. Lenz's law is a form of the law of conservation of energy, since it states that a change cannot propagate itself. See Conservation of energy, Electromagnetic induction


McGraw-Hill Concise Encyclopedia of Physics. © 2002 by The McGraw-Hill Companies, Inc."

Seems pretty straight forward to me. Hard to beat. The only way to beat it is
not to induce the EMF to produce the current.

I say this because of the part in bold in the quote above. If the change induces
the EMF the EMF is the result of Lens Law. You cannot have the result of a
cause without first having the cause. Simple. The result is opposing the
cause. It's a valid law, it's defined very well. In my opinion.

That's

whenever there is an induced electromotive force (emf) in a
conductor, it is always in such a direction that the current it would
produce would oppose the change which causes the induced emf

The EMF cannot be induced by the change of magnetic flux from a passing
magnet after a delay, if the EMF is not being caused (induced) in real time by
the change that is causing it, then what is causing it ? Because if
the EMF is caused by something else I don't think it has anything to do with
Lens's Law.

The "Lens" current is produced by the EMF induced by the change that caused it, so the
"Lens" current is opposing the change that made it . Always.

I think the Law is valid. The way it's defined, from what I can tell, it's a Law.

Anyone agree ?

[Shadesz]

I agree. Mostly.

The "Lens" current is produced by the EMF induced by the change that caused it, so the
"Lens" current is opposing the change that made it . Always.

I don't agree with this. Well kind of. What if we divert the opposing force to another location in our pickup circuit, so the opposing force isn't seen at the pickup coil itself?

In other words, what if we use lenz law against the 'lenz current' in order to delay the counter force at the pickup coil itself...???

Do you see how that can satisfy Lens law but still allow us to avoid it at our pickup coils?

[marxist]

time is on my side

Lenz's law is:
A law of electromagnetism which states that, whenever there is an induced electromotive force (emf) in a conductor, it is always in such a direction that the current it would produce would oppose the change which causes the induced emf.

I think the Law is valid. The way it's defined, from what I can tell, it's a Law.

As far as i understand it is a natural law.
And if you do not tell people, that the reaction COMES AFTER the action, you lie by omission.
And it is easy to perform this lie, because we do not understand time very well. So everybody is grateful if you leave it (time) out of the equation.

Yet please consider: When the resulting force is appearing AFTER the one that caused it ...
And also consider that you will use alternating current. That is: Your causing force will alternate. It will be positive and then AFTERWARDS, a half cycle later, it will be negative.

When now the reaction (the Lenz-force) to the positive half cycle coincides with the following negative (causing) half-cycle, i.e. with a negative cause...
Do you then still have an "Opposing force"?
Rolling Stones-Time Is On My Side - YouTube

[Shadesz]

Here, this circuit will explain the 'inductor delay circuit' idea.

[Farmhand]

I am adamant about this, the law states that the current produced by the
induced EMF flows in the direction such to oppose the change that made it.

There is no delay in the EMF and any current it causes to be "Lens" current
must be flowing to oppose the change, no other reason, if it's not flowing to
oppose the change it is not "Lens" current.

This is my opinion on the meaning of the Law. It is defined quite well in my
opinion. In a motor generator that change is the magnet on the rotor. If the
magnet is gone then the change that induced the EMF is also gone and then
by default and in retrospect the EMF is also gone so there is no longer any
reason to call it Lenz current.

Lenz's Law cannot by definition have anything to do with assisting the change
that made it, it can only oppose the change that made it.

If there is anything assisting the rotor is has nothing to do with Lens's Law.

[Shadesz]

I am adamant about this, the law states that the current produced by the
induced EMF flows in the direction such to oppose the change that made it.

There is no delay in the EMF and any current it causes to be "Lens" current
must be flowing to oppose the change, no other reason, if it's not flowing to
oppose the change it is not "Lens" current.

Exactly, but notice this circuit, the current doesn't flow right away. It is delayed by a part of time. Open the app and stare at the two circuits and watch how the current flows back and forth. They are out of phase even though the created force is exactly in sync.

Another way to put it is this... you are taking the EMF and storing it as voltage in the series inductor for a degree of the cycle. This is possible because you really are producing a back force instantaneously, only this back force is restricting current flow instead of magnet speed.

[Shadesz]

Lenz's Law cannot by definition have anything to do with assisting the change that made it, it can only oppose the change that made it.

If there is anything assisting the rotor is has nothing to do with Lens's Law.

I agree, but the law doesn't say ANYTHING about moving the location where lenz law takes place. It simply says that it has to take place instantaneously, as it does in my circuit.

[Shadesz]

And inductor...

Due to the time-varying magnetic field inside the coil, a voltage is induced, according to Faraday's law of electromagnetic induction, which by Lenz's Law opposes the change in current that created it. Inductors are one of the basic components used in electronics where current and voltage change with time, due to the ability of inductors to delay and reshape alternating currents.

Notice the bold.... so all we are doing is moving lenz from the pickup coil to the series coil.

I will leave it at that. My mind is made up just as strongly as yours. I know we can divert lenz. Delay is probably a bad term. Divert or relocate are much more appropriate terms.

[Farmhand]

I agree, but the law doesn't say ANYTHING about moving the location where lenz law takes place. It simply says that it has to take place instantaneously, as it does in my circuit.

Well it does and it is very specific. Lens law can only take place in a
conductor with induced EMF caused by a change, and the EMF induced must
be in a conductor that is in a place for the EMF induced by that change to be
induced.

It doesn't need to state a time or place it just needs to state "the change
that induces the EMF" and the time and place are defined. Clearly in my
opinion.

Now I'm not saying that the rotor cannot impart energy to the coil and that
this energy cannot assist the rotor. I'm just saying for that to happen Lens's
law is not involved. It must be something else.

People can call it whatever they like, of course. But I'm not buying it.

The current must flow in a direction to oppose the change that induced the
EMF to be "Lens" current.

If (big if) and when there is a current that flows to assist the change that
induced the EMF that produced the current then it would have to be called
something else.

I say (big if) because once the inducing change is gone, there is no more EMF
induced and so therefore no current produced thereafter by the no longer
induced EMF.

If there is no longer EMF to produce the current. Then any current if there is
any has nothing to do with Lens's Law.

I know it seems like a word game, but I think it is important.

Cheers

[Joit]

I think Lenz Rule do not match anywhere. And it seems more like he comes from a Time, where more Researchers would had put out a great Theorie. Another Problem may is, that it seems he had only DC Motors to play with, but no AC Motors, where no Magnets are involved, but redirected Fields.
Another Problem there seems is, that one Pole has a pushing Force, the other Pole has a stronger drag Force.
When you ie induce a N Pole into a S EMF Field, the Motor will run in Attraction Mode, not repelling. And therefor the opposing Fields follow eachother, but are not repelled.
The Calculation may are still close, but they did do that anyway that way, that they calculated anything, and then fixed it, until it matched her Theories well.
Like it was at calculating Soundwaves, what they fixed 100 years later (1980?)afterwards.
Anyhow i think he trys to describe anything, what someone else did find allready, just dont know, what it was

[Farmhand]

Yes Lens did not discover this I don't think, he just formulated a law with words
to reflect the Law of Nature.

I think he done well to define in words what Nature does.

I don't think that it matters AC, DC, motor, generator, Lens's law applies.

I'm just putting this out there, people can use whatever words they want to
describe anything they want.

In my opinion trying to break Lens's Law, would be like trying to catch the
shadow caused by a flashlight in the light-beam of the same flashlight. As
soon as you try, it's gone.

[dragon]

Soooo... how would lenz law apply to an open circuit ( or system )?

[citfta]

Hi Farmhand,

You are right in the way you see Lenz's Law. Anytime a current is induced there is an opposition to that current. What Shadesz is mixing up is current and voltage. The voltage can very well lead or lag the current. If we delay the current for a time then we can have voltage without Lenz. As soon as the current starts to flow then we have the beginning of Lenz's Law effect. Keep digging, you have come a long way in your understanding of electronics in the past year or so that I have been following your posts.


Carroll

[Farmhand]

Soooo... how would lenz law apply to an open circuit ( or system )?

Is that a trick question. Just kidding.

I think Lens's Law is kind of a loophole to support the theory that all systems
are open, to some extent at least.

Which is a very good point to consider as well. That could have some
ramifications of it's own.

I don't think we can "lock", Nature out of our systems (circuits). Our circuits
are part of Nature and the overall system as is everything else. And I think
Lens's Law is a reminder of this.

I think you bring up a very good point Dragon.

ie. A perfect vacuum cannot be created. Nature won't allow it.

[Joit]

Farmhand,
I did read your Post before you did it edit.

The Problem i see at the Main Theories is, they did take a Motor apart, and try to describe every Part by itself, and wonder at last, why they cant put it together anymore, just see some PArts, what do work.
I would had suggest, you talk with someone, who has a lot experience, and can think out of the Box, but, well, after the Replies..
Mainly i think, its better, to stay at the Basics, and find your Way from there, and not from all the Theories.
It may can be, that Lenz tried to find a Rule about the Energy, what is induced in a Coil, when Wires are over eachother, and the same happens, when you pass a Magnet. But wasnt Maxwell as same far?

But when i look at Ciftas Reply, i am sorry, but

Anytime a current is induced there is an opposition to that current. What Shadesz is mixing up is current and voltage. The voltage can very well lead or lag the current. If we delay the current for a time then we can have voltage without Lenz. As soon as the current starts to flow then we have the beginning of Lenz's Law effect. Keep digging, you have come a long way in your understanding of electronics in the past year or so that I have been following your posts.

Anytime a Current is induced... What IS Current, its mainly a Term for Strenght.
Can you even then use it as 'Induced'?
Mixing Voltage and Current? Voltage can very well lag current? What IS Voltage? A Term from moving Current? But dont say, it are magically moving Electrons. Ever induced HV into a high Amperage Coil? There will not much happen at the Coil, only some Spikes, what run THROUGH the Amperage, but not slowing them down.

Cifta, you are a well trained electrical Mind, but your Explanations only give more Questions as Answers, what i can reproduce. It maybe would be better, we have something, what is not only teached and taken over, because it fits at simple Devices.