Advanced and Delayed magnetic fields

[TinMan]

Didnt know what section to post this,so this one seems to be close.

This thread is about advanced and delayed magnetic field's-no lenz delay PLEASE

Below is a video of a generator that uses two ferrite C core's to form the complete ferrite core assembly. As you will see in the video,the secondary coil recieves most(about99%)of it's magnetic flux from the primary coil(once the primary is loaded).How ever,there seems to be a bit of a mystery here,as the current in the secondary is leading in phase when the load is reduced. This brings the question-->how can it be recieving the magnetic field from the primary before the primary starts to produce current?.

It should also be noted that the secondary(regardless of load) in no way reflects a CEMF to the rotor. So enjoy the video,and post your thoughts.

Guru's?

https://www.youtube.com/watch?v=FFwIF4B7BP4

[PhysicsProf]

Tinman asks:

How ever,there seems to be a bit of a mystery here,as the current in the secondary is leading in phase when the load is reduced. This brings the question-->how can it be recieving the magnetic field from the primary before the primary starts to produce current?.

I'm not sure; but here is a possible answer.

We sometimes think that electromagnetic induction requires a significant but changing Magnetic field B to be present, as when moving a permanent magnet through a coil of wire.

But Faraday's law of induction does not require a significant (non-zero) B, it just requires that the magnetic field (or better, flux) be CHANGING.  The more rapid the change, the larger the Electromotive force E*
E* = - N d(phi)/dt  
Note that B does not appear; so the magnetic field passing through the coil may be ZERO, as long as it is CHANGING.

So perhaps, tinman, you have a large change in B coinciding with ~zero B field, in which case the induced current in the secondary can be large (even though B is approximately zero).

This is actually a very interesting case, more generally, rather than having a growing magnetic field to cause an induced current, simply have a rapidly varying B that stays at approx zero - oscillating around zero -- and look at the induced current.  

Pressing further, a very small but rapidly oscillating current in a one-or-few loop primary at high-frequency may induce a large oscillating current in a secondary (approx. the same number of loops as the primary, say).  IDk, something I haven't really thought much about/along this line before...

[BEP]

Tinman,

You should probably keep in mind that any repeating cycle can be thought of as circular.

The question you might wish to ask yourself is;

Is that signal leading the other one by ~15 degrees or is it actually lagging by ~165 degrees?

You might have a better picture of what is actually going on by setting your scope up to display the phase relationship using Lissajous Patterns.

[TinMan]

Tinman,

You should probably keep in mind that any repeating cycle can be thought of as circular.

The question you might wish to ask yourself is;

Is that signal leading the other one by ~15 degrees or is it actually lagging by ~165 degrees?

You might have a better picture of what is actually going on by setting your scope up to display the phase relationship using Lissajous Patterns.

Being so close(the two coils)and on what is essentially 1 core,i wouldn't think they would be out by 165*. I am also triggering off a small coil as seen in the video. The primary wave form dose not move relative to the triggering coil,only the secondary.

[TinMan]

Here is a sensitivity test i did,and also a core material drag test between laminated steel and ferrite cores.

https://www.youtube.com/watch?v=uAXtB_7RkEg

[TinMan]

Tinman asks:
I'm not sure; but here is a possible answer.

We sometimes think that electromagnetic induction requires a significant but changing Magnetic field B to be present, as when moving a permanent magnet through a coil of wire.

But Faraday's law of induction does not require a significant (non-zero) B, it just requires that the magnetic field (or better, flux) be CHANGING.  The more rapid the change, the larger the Electromotive force E*
E* = - N d(phi)/dt  
Note that B does not appear; so the magnetic field passing through the coil may be ZERO, as long as it is CHANGING.

So perhaps, tinman, you have a large change in B coinciding with ~zero B field, in which case the induced current in the secondary can be large (even though B is approximately zero).

This is actually a very interesting case, more generally, rather than having a growing magnetic field to cause an induced current, simply have a rapidly varying B that stays at approx zero - oscillating around zero -- and look at the induced current.  

Pressing further, a very small but rapidly oscillating current in a one-or-few loop primary at high-frequency may induce a large oscillating current in a secondary (approx. the same number of loops as the primary, say).  IDk, something I haven't really thought much about/along this line before...

I will be putting together a solid state version soon Steve,so we will be able to have a look at your last paragraph.

Thanks for the input.

[Matt Watts]

Being so close(the two coils)and on what is essentially 1 core,i wouldn't think they would be out by 165*. I am also triggering off a small coil as seen in the video. The primary wave form dose not move relative to the triggering coil,only the secondary.

First, if you suspect you have a condition where the effect is happening before the cause, try slowing things down and see if the two waveforms begin to align.  If instead you see a large swing as you slow things down, you can be pretty sure the effect is actually a full cycle (or multiples) behind the cause.

[BEP]

Tinman,

On your core drag experiment...

I would think the steel causes more drag because eddy currents are easily produced in them where ferrites are formulated to prevent eddy currents.

On your initial question in the beginning of the video of where might the peak induced voltage be generated....

My opinion is when the core is between rotating magnets. 

[TinMan]

Tinman,

On your core drag experiment...

I would think the steel causes more drag because eddy currents are easily produced in them where ferrites are formulated to prevent eddy currents.

On your initial question in the beginning of the video of where might the peak induced voltage be generated....

My opinion is when the core is between rotating magnets. 

Yes,eddy current's-thought i said that in the video?.
And yes again,when the core is seeing or recieving the greatest field change,is when the core is between the two magnet's(north/south). You would be supprised at how many people think the peak voltage,and current is reached when the magnet is at the center of the core.They think that because the magnetic field is strongest in the core when the magnet is closest,is when maximum power is reached by the coil. What they dont realise is that is when the rate of change is at it's minimum,and that is actually when the sine wave is at the 0 volt line.

[Erfinder]

Yes,eddy current's-thought i said that in the video?.
And yes again,when the core is seeing or recieving the greatest field change,is when the core is between the two magnet's(north/south). You would be supprised at how many people think the peak voltage,and current is reached when the magnet is at the center of the core.They think that because the magnetic field is strongest in the core when the magnet is closest,is when maximum power is reached by the coil. What they dont realise is that is when the rate of change is at it's minimum,and that is actually when the sine wave is at the 0 volt line.

wavewatcher beat me to the response....The peak induced is between the magnets.  This is the basis of most machines we learn about.  I built several machines which allow me to take full advantage of the vectors generated at these locations.  The problem with this topology is to be observed in the fact that the induced and inducing are not coincident.  As you have suggested Tinman, the majority assume that the peak voltage manifests when the coil and magnet are perfectly aligned, this is terribly wrong, but wouldn't be if the proper understanding was in place, and practiced. In my opinion, its as if folks instinctively know what needs to be but aren't in the position to make it happen.  I now appreciate the need for the peak induced voltage to manifest at the location which has been heretofore identified as being the zero crossing, and have learned how to configure my systems so that this takes place.  There are many reasons why this change is paramount, the least of them being that induced and inducing currents are in phase with the induced voltage, geometrically.......with this simple phase correction, the door for geometry based resonance is thrown wide open.


Regards

[TinMan]

wavewatcher beat me to the response....The peak induced is between the magnets.  This is the basis of most machines we learn about.  I built several machines which allow me to take full advantage of the vectors generated at these locations.  The problem with this topology is to be observed in the fact that the induced and inducing are not coincident.  As you have suggested Tinman, the majority assume that the peak voltage manifests when the coil and magnet are perfectly aligned, this is terribly wrong, but wouldn't be if the proper understanding was in place, and practiced. In my opinion, its as if folks instinctively know what needs to be but aren't in the position to make it happen.  I now appreciate the need for the peak induced voltage to manifest at the location which has been heretofore identified as being the zero crossing, and have learned how to configure my systems so that this takes place.  There are many reasons why this change is paramount, the least of them being that induced and inducing currents are in phase with the induced voltage, geometrically.......with this simple phase correction, the door for geometry based resonance is thrown wide open.


Regards

I'm hopping that you will share some designs Erfinder. No more teasing please lol.