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Author Topic: Dynamic magnetic domain analysis  (Read 4255 times)
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There appear to be few people who treat magnetic circuits in the same way that we treat electric circuits, so the inner workings of generators and transformers is quite often a bit of a mystery.  This thread tackles that problem and shows that we can do dynamic analysis in the magnetic domain if we want to.  If we are not happy with the differential or integral calculus then we can use ready made programs like Spice to do the work for us.  All we have to do is recognize that magnetic "components" act in similar manner to electrical ones, so we create an equivalent circuit that looks like an electric one, treating flux like current and mmf like voltage.  Here is a paper I wrote many years ago analyzing transformers in the magnetic domain.  Of interest is the method for modeling PM's since they are an important feature of many prospective OU systems.

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Not feeling too well at the moment, horrible tummy upset with lots of pain.  And this coincides with what I think is the most important revelation in my OU career.  I will write this up in detail but meanwhile here is the gist of the approach.

You will note that I recently posted about eddy current heating and also about PM generators having OU and UU regions that are not generally recognized (wrongly posted under the pulse motor thread).  Well it turns out that there is a common feature linking these two and this becomes strikingly obvious when you analyze things in the magnetic domain.  When you operate a PM generator outside its normal regime by loading it too heavily with a low resistance load you get into the regime where the reactance of the coil becomes greater than the load resistance thus introducing considerable phase shift between induced voltage and current.  You don't normally notice this phase shift because you measure only the voltage across the load resistor and that has to be in phase with the current through it, what you can't get at is what is going on magnetically.  There is the usual dilemma that the induced voltage comes not just from the changing flux due to movement in a magnetic field, but also from the flux due to the current flow and these add vectorally when considered as phasors.  This dilemma is solved when you create the magnetic domain solution where the PM is modeled as a mmf generator in series with a reluctance, and air paths are modeled as reluctances.  A coil connected to a load resistor is modeled as a magnetic inductor obeying mmf=-L*dPHi/dt.  It then becomes clear that when the coil is in line with the magnetic poles, at the point where torque is zero, there is present this dPhi/dt changing flux that is driving current through the load and that is not coming from the movement, but from the magnet-to coil circuit that involves the mmf of the magnet, the magnetic resistances (actually air reluctances) and the magnetic inductance (the loaded coil).  Truly at that point the load power is coming from the magnet's mmf, not from the mechanical drive.  You can look upon the coil movement as a form of magnetic switch that switches the coil into the magnetic circuit, then the phase retarded flux flow becomes obvious.  You end up with some seemingly weird results, like power is proportional to 1/N^2, IOW you need minimum turns.  This explains why the eddy current system works well since you can't get less than a single turn.  Lots more to come on this.

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Hi Smudge
Hope you start feeling better soon, no rush for major breakthroughs  :)

I have a setup which maybe ideal for testing some of this stuff, we built the Romero motor/generator.

During my tests i tried to study the magnetic field during energy generation, using a hall sensor i could see a magnetic lag during acceleration and an advance during deceleration
OR was it the other way around, i would need to revisit the my posts to correct that.

Here's some posts with video's


This video shows the setup, 2 coils are driving the motor side the rest are generators, the setup is a plastic disc with magnets that can rotate, we use a coil on the top plate in series with a coil on the bottom plate, these coils are in series and have a ferrite slug, on top of each coil is a metal washer with a magnet on top.

http://www.overunityresearch.com/index.php?topic=862.msg14857#msg14857

Phase shift of magnetic field during acceleration, measured using a hall sensor and a rpm sensor.
http://www.overunityresearch.com/index.php?topic=862.msg15738#msg15738

Maybe this setup can be used to study things, it is possible to connect a load to the generator coils at precise positions of the magnet pass during generation.
« Last Edit: 2014-09-22, 19:11:22 by Peterae »
   
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From Smudge:

Quote
Not feeling too well at the moment, horrible tummy upset with lots of pain.

There seems to be a lot of this going around, nearly everyone I talk to is experiencing some form of gastrointestinal upset / pain. Anyone else seeing this?

We appreciate your work and hope you can have a rest and recovery.



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There seems to be a lot of this going around, nearly everyone I talk to is experiencing some form of gastrointestinal upset / pain. Anyone else seeing this?

For a couple of years now.   Original self-diagnosis was gluten intolerance/sensitivity, but I'm thinkink now that any excess of starch or sugar is an issue.  Combined with other things such as beer making my kidneys feel like they have needles in them, and recurring gastrointestinal inflammation even without gluten, have led me to look at GMO's.  There is a link with gastrointestinal flora vs yeast (candida), but I'm not sure what's going on.  Yeast do thrive on sugars and starches.  GMO yeast?

At the moment, I am taking a variety of anti-fungal products to kill the yeast, and then a separate pill flora pill to re-establish a healthy balance.

My original sudden change diet was to cut out sugars and starches, and this clears up all symptoms in about a month, but it's very hard to maintain.
   
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OK, I've written my paper looking at magnetic domain circuits for generators.  Although I deal with a simple variable reluctance generator the principle still hold for more conventional generators where an armature rotates in a magnetic field.  You can model this by variable reluctance paths between the pole faces and the armature.  And the math clearly shows it is possible to get a 90 degree phase shift armature reaction that places the peak load current at an armature position where it cannot produce drag torque.  Normally any attempt to use a generator with the load resistance needed for this 90 degrees results in all the power dissipated in the coil which is why this is not normally done.  But being clever engineers I see no reason why we can't develop an unusual generator that is OU.  Incidentally even at that 90 degree phase there is still significant power being generated, it's just at very low voltage high current.

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I am going to have to dig jp the old rotary transformer, as this may be the thread that can explain why my setup dose what it dose.

Will try and dig it up during the week smudge, and see what you think.


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I got home early enough to go hunt down those old motors of mine that i used in previous experiments. So apon throwing the scope across a load resistor and the coil,i found what looks like a voltage inversion across the generator coil when loaded on one side of the Ac wave.

See what you make of it Smudge.

Brad

https://www.youtube.com/watch?v=BsrkcOQYT5E


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One thing it does show is that loading a generator doesn’t necessarily add drag torque, in fact it can do exactly the opposite.  When I got your video up I saw there are several other examples of generators speeding up under load, even a dead short has the effect.  This is all predictable and the only reason that OU isn’t normally achieved is because the power is lost in the output coil as heat.  When you get such large armature reaction I think it can be shown that energy comes out of the magnet, not out of the shaft.  So if you could use the coil heat as an output it should show OU.  The eddy current heater does just that.

As regards your phase inversion I see it gradually builds up, it is not instantaneous.  My guess this has something to do with the fact that you have a combined motor-generator and you are seeing armature reaction gradually changing phase as the motor speeds up.  Thanks for doing the test.

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One thing it does show is that loading a generator doesn’t necessarily add drag torque, in fact it can do exactly the opposite.  When I got your video up I saw there are several other examples of generators speeding up under load, even a dead short has the effect.  This is all predictable and the only reason that OU isn’t normally achieved is because the power is lost in the output coil as heat.  When you get such large armature reaction I think it can be shown that energy comes out of the magnet, not out of the shaft.  So if you could use the coil heat as an output it should show OU.  The eddy current heater does just that.

As regards your phase inversion I see it gradually builds up, it is not instantaneous.  My guess this has something to do with the fact that you have a combined motor-generator and you are seeing armature reaction gradually changing phase as the motor speeds up.  Thanks for doing the test.

Smudge


If i dead short it across the diode insted of burning it off in the resistor,the motor dose indeed speed up a lot faster,and with a higher RPM. The phase inversion looks slow as the scope is set on average 16X. This is because the traces are very noisy on peak or sample detect. I will try setting the scope on sample,so as we can see the change as it happens. As we are using the top half of the wave (as per diode direction)to get the speed under load effect,i assume that insted of the magnetic field being apposed to that of the field of the rotor,it must be an opposite field,and is attracting the rotor toward it. This seems to be opposite to that of what it should be. Could it be something to do with this phase inversion ?.


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If i dead short it across the diode insted of burning it off in the resistor,the motor dose indeed speed up a lot faster,and with a higher RPM. The phase inversion looks slow as the scope is set on average 16X. This is because the traces are very noisy on peak or sample detect. I will try setting the scope on sample,so as we can see the change as it happens. As we are using the top half of the wave (as per diode direction)to get the speed under load effect,i assume that insted of the magnetic field being apposed to that of the field of the rotor,it must be an opposite field,and is attracting the rotor toward it. This seems to be opposite to that of what it should be. Could it be something to do with this phase inversion ?.

It's probably not quite like that since you have a combined motor-generator.  The motor is creating its own magnetic fields complete with armature reaction and your coil current is adding or subtracting from that reaction, making the motor do different things.  So it could be that your added field is making the motor attraction greater or less than otherwise which is not quite the same thing as your field actually doing the attraction.  But I could be wrong :-\

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It's probably not quite like that since you have a combined motor-generator.  The motor is creating its own magnetic fields complete with armature reaction and your coil current is adding or subtracting from that reaction, making the motor do different things.  So it could be that your added field is making the motor attraction greater or less than otherwise which is not quite the same thing as your field actually doing the attraction.  But I could be wrong :-\

Smudge
This is why i called it the rotary transformer-way back when. There are a few video's of this setup on my YT channel. My intentions were to use the force you would have between the transformer coil,s to create rotation. if we cut the core of a transformer between the two coils(primary and secondary),when we loaded the output coil,the two halfs would want to puch apart. Well i still think this is what's happening here. i believe the rotor section that becomes magnetised,is becoming magnetised just after mid point of the generator coils core. So when we load the generator coil when the magnetic field is building on the rotor,like poles are produced,and the generator coils field pushes the rotors field away(repulsion).This brings to mind a design for a very efficient electric motor that we can draw power from without it effecting the P/in to the motor it self. When time permit's,i may have a closer look at this.


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Bump.

Verpies wanted a reference to my magnetic domain paper so I have bumped this thread to bring it into view.  Paper is attached to the first post.
Smudge
   
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