Author Topic: Poynting vector  (Read 1388 times)

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Poynting vector
« on: February 26, 2014, 09:45:02 am »
Hello

I was reading about toroidal magnetic fields and came across the concept of Poynting vector which is the cross product of the E field source of primary currents and the B field source of secondary induced current.

The Poynting Vector tells the flux of Electromagnetic energy that flows from primary to secondary. (if i understood it correctly)

Than seems it could be possible to manipulate the amount of energy received from a secondary coil if in it is there already a magnetic field of itself.

If this is true i also may have found a way to just amplify energy supported by well know physics law...

(http://upload.wikimedia.org/wikipedia/commons/thumb/4/4c/Toroidal_Transformer_Poynting_Vector.jpg/800px-Toroidal_Transformer_Poynting_Vector.jpg)


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Interesting experiment
« Reply #1 on: February 26, 2014, 10:50:48 am »
Non related but here it goes

Today i made a very intriguing experiment, with one magnet and two magnetic coins.

I found that if you provide a separator between the first coin and the magnet (like a piece of wood or glass...) if the other second coin touch the 1 coin you can pull the two coins away from the magnetic field up to the point that the first coin drops when the induced magnetic dipole in the two coins decrease the attractive force.

Could you help me think about the implications of this?


How can be the coin 1 x  coin 2 attraction stronger than the magnet x coin 1 attraction?


seems like the induced dipole dipole interaction force is stronger than the permanent dipole versus induced dipole 1

how is that possible?

what can we learn from that?

I tested also transformer laminations and the same effect happens


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transfomer
« Reply #2 on: February 26, 2014, 11:51:09 am »
Analysing again a transformer i found that:

the primary has an initial inductance and if connected to a source of power a current start to flow even having no load at the secondary.

If a load is connected to the secondary the current in the load will depend on the impedance of the secondary plus load resistance... Z complex impedance

this current generates a opposing magnetic field that reduces the primary field but not at the same rate.

the secondary current is proportional to the load resistance, the primary current increase is proportional to the mutual inductance action to reduce the primary effective inductance... 

So the induction reaction force only exists when theres induction going...

So this differential inductance created when the load is connected to the secondary that reacts by consuming amps on the primary.

I think than, that if a permanent magnetic field coil can interact in a pulsed transformer in such a way as to never let the core reach saturation for example is contrary mag fields are created.


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Re: Poynting vector
« Reply #3 on: February 28, 2014, 07:37:10 am »
well in every setup I could think of where induction was present I couldn't get rid of lenz law.. the only place where lenz law doesnt apply is the motional emf..meyer have used this in the generator and I think he used it inside epg... and fuel cell..

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Re: Poynting vector
« Reply #4 on: February 28, 2014, 07:38:46 am »
two charges moving parallel....

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Re: Poynting vector
« Reply #5 on: February 28, 2014, 10:43:49 am »
I think you are correct.. i have a new idea .... new threads =)