Rotating Magnetic Field's and Inductors.

[MileHigh]

Inductance meters are arguably like car "idiot lights" or the newer term "numbers in boxes."

You can watch the inductance in action on your scope, experiment with both current/magnet directions, and as a bonus find the saturation point for the core.

From a YouTube search:

https://www.youtube.com/watch?v=01Ebd6eR7Lw

https://www.youtube.com/watch?v=74fz9iwZ_sM

https://www.youtube.com/watch?v=GF4AbbBGa5M

https://www.youtube.com/watch?v=RhS8m38ef0Y

Honestly any serious experimenter needs to be able to measure capacitance and inductance with his scope and a few support components.

[MileHigh]

Well, I looked at those four clips after the fact and I didn't like any of them because they are all based on frequency measurements.

I wanted a clip that measures the L/R time constant Tau.  That way you can see all of the action in real time.  You can also lower the resistance more and more so that the final current is such that the core is fully saturated.  So you can determine the saturation current for a given coil + core material and hopefully observe the anomaly in the waveform as you break through the saturation level.

I couldn't find a clip that demonstrated that so I marked up a screen cap.  With the attached setup you can look at the rising current waveform in real time and play with your magnets and such.  Just measure the Tau and take it from there.

As far as I am concerned this pulse-based system is a "truer" inductance measurement because you are looking at the actual exponential current waveform.   You have the option of measuring the inductance at different final current values to "feel out" how the core material is responding to different final B field intensities.

This is the real Spice.

I attached a second image with the math.

[MileHigh]

After that very helpful posting if I see one more jackass try to tell me what a horrible person I am, then they can shut their mouths and kiss my ass.

[tinman]

 author=poynt99 link=topic=16261.msg470474#msg470474 date=1452128234]

I think you are the only one waiting for something to happen, that I have already said 2 or three times, is not going to happen. 

Interesting. I have never seen you give up so easily with your sim replication's.

Listen up Mr., as long as I retain free will, neither you nor anyone else is going to dictate what I do with my free time! I don't have to justify bugger all to you, and its your problem if you can't see the sensibility in my decision to build rather than simulate. You should be bloody well more than satisfied that I am even willing to do that!

The only reason your willing to actually build a device,is the need to beat me,and prove me wrong.
You failed at your first attempt,and now are seeking a second go at it,and as Luc pointed out-with the bases loaded in your favor. But non the less,i accepted your challenge on the condition that you accept my request that you finish what you started with your sim--that was suppose to show nothing out of the ordinary was taking place with my(and Luc's) DUT's. So !!Mr!!,i am not satisfied that you are unwilling to complete and finalize your sim version of my DUT-that you took upon your self to do.

That is your over all claim of this thread? Is that so? No, You're moving the goal posts again.

No,it's not. You only have to follow the thread to see that as i experimented more and more,what i thought may be what was happening,turned out to make no sense.
Example- post 238 Quote: If the magnets were increasing the effective inductance of the coil,why dose this increase not happen when the magnet(either pole) on the rotor is stationary in front of the coil?.
I think the rotor magnets are inducing an EMF across the coil,and it is this EMF that is the cause of the reduce P/in,as the battery now dose not have to supply that bit of energy to create that EMF that already exist.

So you see Poynt,as i kept on moving along with experiments,i also worked on making what i thought make sense. As you can see,i was thinking along the same lines as you--no increase in inductance was taking place,but the effect was to do more with the EMF being produced across the coil by the moving magnets.

My challenge is to that statement, not to whether the inductance is increasing or not.

Really?. Lets have a look at your post-post 253-Quote: An observation from the two scope shots:
It appears that the reduced current during the ON time is a result of the negative-induced voltage in series with the battery voltage. I presume Pin goes down with the rotor installed.
So is there a problem or something that apparently hasn't been explained?

Yes,there is a problem !or something! that was yet to be explained.

Here was my next thought as to what may be taking place to reduce the I/in-P/in,after i had discounted the produced EMF across the coil by the external magnetic fields.
Post 262- Quote: This is exactly what i said some pages back,so lets run with this for a bit,and think about what is happening during each cycle. We do know which comes first(the chicken or the egg) in this case,and that is the induced flux into the core from the PM's. We know this because we have alternating fields on the rotor. The coils produced field at the rotor end is north,so the other end of the coil will be of course a south field(we will stick to N&S as it makes it easy). We know that the magnetic domains within the core will align opposite to those in the PM,and so will be aligned the same when the coil has a current flowing through it. So the induced flux in the core from the PM's is now present before the coil switches on. This in turn lowers the P/in needed to raise the flux volume in that core and it's surroundings to the level we had without the rotor-->this we know,as the P/out dose not change,which tells us the field in and around the inductor was the same in both cases. The extra waste heat dissipated by the coil when the rotor is not in play,is due of course to more current flowing through the coil. The extra current flow is due to the fact that it now has to induce the flux into the core as well,where as with the rotor,the flux is already induced !mostly!,and the domains are !mostly! already aligned within the core material. So from this we know work is needed to induce the flux into the core,and align the magnetic domains within that core-->and we also know that this work being done came from the magnets when the rotor is in play. So lets use some example numbers here-that being the power required to spin the rotor,and the reduced power that the magnets on the rotor cause.

Post 269 in regards to your post 253-Quote: My explanation was regarding how or why Pin decreases when the rotor is used.It is an explanation if you put a little thought into it. I'm done spoon feeding.

So as we can see,you had made up your mind that it was this reverse voltage across the coil that the magnets on the rotor produced,that was the cause for the reduction in P/in and increase in P/out.

Post 270-my post after gaining further information from the tests i had been carrying out,and when a true understanding started to make sense of what was happening with my DUT.
Quote: The reduced P/in with the rotor is more to do with the induced flux into the inductors core,and not the induced negative voltage.

Now i will just requote what you wrote above=
Quote:My challenge is to that statement, not to whether the inductance is increasing or not.
Your post-272-Quote: That does not make sense. In fact it is opposite to what happens. Are you thinking that the inductance, and hence impedance of the coil increases when the magnet is flying by? No, it would decrease.

Your post 273- Quote: What are your thoughts Brad on trying a solid state version to achieve the same effect?
I was all for this solid state version being done to see the !!same!! effects.But we will get back to that later on in this post.

My reply to your post 272--post 274
Quote: That is actually incorrect.
The inductance rises when there is a changing flux value in the core of the inductor/ over time. Only when the flux value is constant,is there a reduction in the inductance value. As the magnetic flux is never a constant value in the core of the inductor when the rotor is in play,then the inductance value of the inductor is indeed higher than it would be without the rotor.

Your post-276 Quote: Do you have data or a technical reference to back that up? It goes against the physics of how cores work. If the core's magnetic domains are anywhere other than their neutral position (i.e. non-polarized) at the instant the coil fires, then the coil's inductance will be reduced, regardless if the domains were in rotation or were static at the time. The core is partially or fully polarized in either case.

Your post 277-Quote: I have one SS version to offer here, and you are close. Mine uses another coil yes, but it doesn't require another power source.The effect has been verified AFAIAC, and confirms my explanation offered earlier. My Conclusion? Nothing extraordinary going on here.

One of your comments on post 279 Quote: Take it as it is, there is no miracle action at hand here, just good old fashioned electrical theory. We all went down a similar road years back with Luc's Capacitor energy transfer experiments, which I also did a big paper on.

Your post on post 285-Quote: I honestly am beginning to think that one reason folks seem to learn too little around here, is because they are being spoon fed the answers all the time; yes by guys like me, verpies, MH, TK et al. Check out citfta's link, or google "inductance" and "frequency" together. Here is another link. Perhaps you'll learn more by digging some answers up yourself.

Which is what i have been doing with the tests i have been carrying out with my DUT--not from some books or laws !!theories!.

Your post 326 Quote: As I said Brad, the simulation could use some fine tuning to not only increase the effect, but maintain or increase the flyback power as well. I just don't have the will nor desire to do so. But I am confident it can be done.

I am confident that OU machines can be made,but that is neither excepted or proof. Your sim results did not simulate the results from my DUT,as you made claim to above-Quote: The effect has been verified AFAIAC, and confirms my explanation offered earlier

No-no it has not been verified at all,and that is a false statement you have made.

Your post 360-Quote: I gave you one method to achieve the same effect without using magnets. If you are interested in seeing it done without them, why don't you build it?

No-no you did not give me one method to achieve the same effect,as you did !NOT! achieve the same effect as my DUT with your sim. Why dont i build it you ask-->why dont you finish your sim project,and show that the same effect can be achieved without actual permanent magnets in motion?.

After reading all that,i will now re-quote your statement above
Quote:My challenge is to that statement, not to whether the inductance is increasing or not

Well that is not what you have posted throughout this thread-and it's all there to read as i posted above.

After all that,here is the kicker
Your post-392 Quote: There is one way I can think of that might increase the inductance of a cored inductor, but only momentarily during the ON time, which of course is what we are dealing with here.

After all your dismissive posts about an increase in inductance,your posts both on this thread and Luc's as to how what we think go's against some law's of inductors,and we have nothing out of the ordinary happening-->you post the above statement ,a statement that resembles my exact setup--my DUT-->which of course is what we are dealing with here

After all you have posted throughout this thread,you then have the balls to post this-
Quote: Anyway Brad, I could have a field day with your recent posts, but alas I choose to do other things with my time, because it is not worth it. My past dealings with Rosemary Ainslie taught me a great deal about dealing with "difficult" people and when one's time is worth investing and when it is not, so I will remain reserved.

Are you Fn serious Poynt 
And this-
Quote: You would be wise to stop tirading about and instead do something extraordinarily productive with that magic ssg rotor of yours. But I wouldn't want to tell you what you should do with your time now, would I?

Never did i think you would ever turn out to be some one like this Poynt.
Most of your post here on this thread(and Luc's) dismissed any possibility that the inductance could be increasing,and that being the cause of the increase in efficiency--even to go as far as simulating the effect--which you failed to do.

I have been learning-understanding as i go-reasoning with what my tests were showing me,and making sense of them. You on the other hand just went straight for the !!nothing out of the ordinary!! happening here,and decided it was the induced reverse voltage that was causing the effect.
You then have the ordasity to say to me--> You would be wise to stop tirading about and instead do something extraordinarily productive.

So go ahead Poynt--have a field day with my post on this thread.
But before you have a go at me like you have,take the time to go and read the whole thread,and remember the things you have said throughout that thread.


Brad.

[verpies]

, so we have to assume the meter is not DC pulsing the coil the get samples, it is using AC.

This difference comes down to the absolute permeability of the core vs. the differential permeability of the core, respectively.
Inductance is proportional to one of these permeabilities.  Can you guess to which one?

Hint: Inductance is the ratio of Flux linkage to Current.