Some results of the first run.
The neo's had to be swaped out for ferrite magnets,as they were far to strong.
Measurements are as follows after some fine tuning,and the resistor across the secondary coil is 81.7 ohms. Tank cap is not yet in place.

Without magnets
P/in=12 volts@ 7.79mA=.0934watts
P/out(flyback)=12.43 @ 4.45mA=.0553watts
P/out(secondary/resistor)=400mV/81.7 ohms=.00196watts
P/out total=.0553+.00196-.05726watts.
Efficiency is 61.3%

With magnets
P/in=10.4mA @12volts=.1248watts
P/out(flyback)=12.44 @6.8mA=.08459watts
P/out(secondary/resistor)=920mv/81.7ohms=.01036watts
P/out total=.08459=.01036=.09495watts
Efficiency is 76.08%

Both meters are of the same type,and were set at the mA scale,and large smoothing caps used on input and output.
Meters were then swaped over,and test ran again. The results are an average of the two test.
The two DMMs used have a .02mA difference.
The smoothing caps on the input were 1x 10 000uf high current cap,and two 4200uf caps.
Cap used on the flyback output was 1x 10 000uf high current cap.
No ripple detected across the two DMMs.

The first scope shot shows the device running without the magnets in place.
The second scope shot shows operation with magnets in place.
Scope shots taken befor fine tuned.

...
Gyula:

I didn't know that a magnet would have such a low relative permeability.  You still might be able to take advantage of the polarization though as has already been stated.  Note the excitation from the primary coil is unidirectional.  This assumes the relative permeability is radically different depending on the direction of the external field.  It would be an interesting and easy test.  You just have to look at the slope of the current rise in the coil for same-direction and opposite-direction magnetic field generation by the coil wrapped around the magnetic core.  You cross your fingers and hope that you don't ruin the magnet.

I also wonder if the L-meter will be thrown off by the introduction of a magnet into the coil.  I assume they sample or sweep low-level AC frequency excitation for the coil under test and check the response to measure the inductance.  So if the magnet does indeed radically change in relative permeability depending on direction it may have a small heart attack (throw off the measurement algorithm).  It probably will read out as a high inductance - my guess.

Another point is that this is a transformer setup, not an inductance.  So assuming the core (any core) is coupling the energy properly, you _don't_ see inductance on the primary, you see the load, which is an LCR circuit.  So you see a wobbling resistance!  lol  Note since you are approximately at resonance, you are pretty much seeing the resistive component of the LCR circuit as the load of the primary.  So that means that Brad should see the voltage and current going into the primary winding as mostly in phase, assuming that the core/coupling is doing it's job properly to transfer the power.

MileHigh

Hi MileHigh,

Yes permanent magnets are almost fully saturated magnetically, many FE tinkerers are not aware of that and when they use magnets in a "closed" magnetic circuit where permanent magnets are used to "close" the magnetic path, they actually build an "air gap" into the circuit at places they insert the permanent magnet(s).

Well, L meters mainly use oscillators inside which excite the coil to be measured with saw-tooth like waveform so there are no abrubt amplitude change across the coil. Indeed you have to be careful when testing coils with magnets when using an L meter and move the magnet slowly in or out of the coil to avoid harmful induced amplitudes, to save the inside oscillator circuit. I did check air core coils with inserting different magnets into them and never had any malfunction in my L meter. The permanent magnet in itself when plugged into an air core coil does not change any of its original properties its permeability also stays the same. The L meter normally use a low power oscillator to drive the coils to be measured.

If you use a coil with ferromagnetic core and attach a permanent magnet to the core or just approach it closely with a magnet, then the permeability of the core can change a lot (it normally goes down) so the L meter shows a decreasing inductance value too. Taking sudden movements with the magnet causes the L meter to go out of range for some moments, then normally it returns to the new L value.

It is okay what you wrote in your last paragraph above, I would add that the load resistance  (earlier the 18 Ohm, now the 81.7 Ohm) establishes the loaded Q of the output tank circuit, and if this load does not change there is no 'wobbling resistance'. If there is no load resistance then indeed the LC tank has its own parallel resonant impedance and it is a high value (several kOhm or even higher) wrt the 18 or 82 Ohm loads, and it is also a constant value (if the switching frequency is stabil).

Gyula

Magnetics and transformers and materials, it's a pretty big subject if you are hard core.  I am too tired to comment on previous postings right now, but let me mention something interesting.  I saw this thread on a science forum but didn't try to read it, it looked like way like too much work and my interest level was not high enough.

The subject was what happens in the magnetic core of a transformer under normal operation.  It's not so obvious.  Think of a good quality fairly large 1:1 transformer.  You put a nice pure 60 Hz sine wave into it and there is a resistive load.  We don't really need to worry about values.

Here is the thing:  The primary current creates magnetic flux in the core.  But the secondary also reacts in perfect synchronicity and its current also creates an equal and opposite magnetic flux in the core.  Since we know that flux in one direction can be cancelled by equal flux in the opposite direction, then what is going on in the core?  If there is no net flux in it, what's happening?  What are the magnetic domains doing?  Are they flipping or not flipping?

We know that each coil in the transformer is creating a "blast of flux."  But between the two blasts there is a kind of mutually assured destruction going on and there is no flux.  It's almost like electrons and holes in a diode smashing into each other and self-annihilating (in a figurative sense).

I honestly have never read up on this subject at all.  I just saw the subject line and it got me thinking.

MileHigh

I think this paper is fairly close to the mark for the layman's needs.

Although it's not second nature to most of us it's not rocket surgery either, if we look in the right places the info is around.

I recommend that anyone interested in transformers and not already trained to read the entire paper from start to finish a few times and use it for reference.
Of course transformers that vary from the efficient power transformer he talks about will behave differently it's a good starting point especially if we want to design our own transformers to use.

Transformers - The Basics (Section 1)
http://sound.westhost.com/xfmr.htm

Preface
One thing that obviously confuses many people is the idea of flux density within the transformer core. While this is covered in more detail in Section 2, it is important that this section's information is remembered at every stage of your reading through this article. For any power transformer, the maximum flux density in the core is obtained when the transformer is idle. I will reiterate this, as it is very important ...

For any power transformer, the maximum flux density is obtained when the transformer is idle.

The idea is counter-intuitive, it even verges on not making sense. Be that as it may, it's a fact, and missing it will ruin your understanding of transformers. At idle, the transformer back-EMF almost exactly cancels out the applied voltage. The small current that flows maintains the flux density at the maximum allowed value, and represents iron loss (see Section 2). As current is drawn from the secondary, the flux falls slightly, and allows more primary current to flow to provide the output current.

It is not important that you understand the reasons for this right from the beginning, but it is important that you remember that for any power transformer, the maximum flux density is obtained when the transformer is idle. Please don't forget this .

3.   How a Transformer Works

At no load, an ideal transformer draws virtually no current from the mains, since it is simply a large inductance. The whole principle of operation is based on induced magnetic flux, which not only creates a voltage (and current) in the secondary, but the primary as well!  It is this characteristic that allows any inductor to function as expected, and the voltage generated in the primary is called a 'back EMF' (electromotive force). The magnitude of this voltage is such that it almost equals (and is effectively in the same phase as) the applied EMF.

Although a simple calculation can be made to determine the internally generated voltage, doing so is pointless since it can't be changed. As described in Part 1 of this series, for a sinusoidal waveform, the current through an inductor lags the voltage by 90 degrees. Since the induced current is lagging by 90 degrees, the internally generated voltage is shifted back again by 90° so is in phase with the input voltage. For the sake of simplicity, imagine an inductor or transformer (no load) with an applied voltage of 230V. For the effective back EMF to resist the full applied AC voltage (as it must), the actual magnitude of the induced voltage (back EMF) is just under 230V. The output voltage of a transformer is always in phase with the applied voltage (within a few thousandths of a degree).

For example ... a transformer primary operating at 230V input draws 150mA from the mains at idle and has a DC resistance of 2 ohms. The back EMF must be sufficient to limit the current through the 2 ohm resistance to 150mA, so will be close enough to 229.7V (0.3V at 2 ohms is 150mA). In real transformers there are additional complications (iron loss in particular), but the principle isn't changed much.

If this is all to confusing, don't worry about it. Unless you intend to devote your career to transformer design, the information is actually of little use to you, since you are restrained by the 'real world' characteristics of the components you buy - the internals are of little consequence. Even if you do devote your life to the design of transformers, this info is still merely a curiosity for the most part, since there is little you can do about it.

4.   Interesting Things About Transformers
As discussed above, the impedance ratio is the square of the turns ratio, but this is only one of many interesting things about transformers ... (well, I happen to think they are interesting, anyway  ).

For example, one would think that increasing the number of turns would increase the flux density, since there are more turns contributing to the magnetic field. In fact, the opposite is true, and for the same input voltage, an increase in the number of turns will decrease the flux density and vice versa. This is counter-intuitive until you realise that an increase in the number of turns increases the inductance, and therefore reduces the current through each coil.

I have already mentioned that the power factor (and phase shift) varies according to load, and this (although mildly interesting) is not of any real consequence to most of us.

A very interesting phenomenon exists when we draw current from the secondary. Since the primary current increases to supply the load, we would expect that the magnetic flux in the core would also increase (more amps, same number of turns, more flux). In fact, the flux density decreases! In a perfect transformer with no copper loss, the flux would remain the same - the extra current supplies the secondary only. In a real transformer, as the current is increased, the losses increase proportionally, and there is slightly less flux at full power than at no load.

MIT Lecture - Inductance.
http://www.youtube.com/watch?v=UpO6t00bPb8

A transformer designed to be efficient can be made to behave like a Thane Crimes transformer just by increasing the applied frequency.  And it will behave woefully. See link.
http://www.youtube.com/watch?v=Zxde9qga79c  Please bear in mind I am no expert and I get things wrong and say the wrong thing at times, but the video shows some stuff in my opinion. I made it quite some time ago. I know a little bit more now. It still makes me laugh, I think I am a funny guy, no ?

..

....
When it comes to the various types of commercial magnets you play with, I would assume that when they "bang" them to magnetize them, the flux density in the magnet is nearly or is 100% strength - they are fully saturated.  So does that imply that the relative permeability is very low in both directions because the magnetic domains are 100% "occupied?"

Yes it does imply. Ferromagnetic materials intended for permanent magnets are magnetically "hard" materials with very high coercivity value, this means that once magnetized to a certain strength they tend to stay at that magnetized level, you cannot control its magnetization as readily and easily as in case of a soft ferromagnetic material. For such hard materials, when the H field is reduced back to zero (or even to an opposite value), the B field in the material does not get reduced but it remains 'remanent' at a certain level.

Here is a link to show the BH curve for a strong and a not so strong permanent magnet,  I refer to Figure 3:  http://www.electronenergy.com/magnetic-design/magnetic-design.htm   

By the way the formula for a BH curve is B=u*H and u (u=permeability) has to be close to unity in case of a material with very wide hysteresis curve.

With a lot of care I would assume that you could demagnetize a commercial magnet and then give it a flux density level of 50% by yourself.  You would have to carefully tip toe up and then down the BH curve.

Yes that would be a hard and arduous task for sure. I would suggest a much easier solution using the so called electro-permanent magnet which includes a soft and a hard magnetic core combination, the soft core serves for a normal electromagnet and the hard core is in fact a normal permanent magnet. By changing the current in the electromagnet the resultant combination of the PM and that of the electromagnet gives a variable and strong magnetic field: http://en.wikipedia.org/wiki/Electro-permanent_magnet 
You surely remember the Hildenbrand or the Flynn setups etc: all such magnetic circuits add magnetic flux from permanent magnets to that of electromagnets, albeit not always in a linearly controllable way but by switching. See these products:
http://www.magnets2buy.com/acatalog/Electro-magnets.html

Gyula

I you wind the wire in a zig - zag manner as seen in your picture, you won't get good results.  The flux produced in individual turns may not add up properly.  Better if you remove a coil from old small generator or a 6 Watts / 12 watts eleminator (rectifier) which will have a small step down transformer in it.    You can see how neatly the individual turns sit one above the other in correct alignment.

Hi Newton
For the purpose of the demondstration,the coils dont have to be neat,as the same loss(if any) will be encountered with and without the magnets in place.
Some time ago,a member here that knows his stuff,said you would only get back 50% at best !on the kickback! to what you put in. As you can see from the result's(which are very accurate),we are getting back 76.08% from the device-even with the messy hand wound coils. But even so,i would have to disagree that neat windings make for a better performance-in regards to these type of systems.I have unwound many inductors,and wound the wire back on neat,and never have i seen a performance increase. Infact i believe messy wound coils are better in this type of system,due to the increased capacitance of the coil.

Brad:

Looking at your scope shots in reply #61 it looks like your current waveform is upside down.  Not a big deal, sometimes inverting a signal on your scope compensates for the "backwards" voltage you might see because of the where the scope ground reference is relative to the probe.

From the top level view you can see that the impedance of the circuit drops and the power consumption goes up when you add the magnet.  So there is more power to go around.

Also, the coupling to your secondary may explain the relatively low efficiency of the circuit.  Ideally you would mate end-on to the laminations for the secondary for both the primary and the magnet.  Instead, you are connecting to the flat tops of the laminations and there are small insulating gaps between each layer.  So the magnetic circuit to the secondary could be relatively poorly coupled.

If you are curious enough, and perhaps for your own satisfaction, with the aid of your digital scope you could make a full timing diagram for the two cases, without the magnet and with the magnet.  If you are good with an image editing program it would be fairly easy to do.  You could take screen captures of all of the signals and then paste them into a large composite image, one on top of the other, everything lined up in time.  You do it for the voltages and the currents on the primary and the secondary, and for the flyback energy collection, with and without the magnet.

You are only looking at less than one-half of the picture right now.  If you were to consider doing it, do it for the resistor only as the load on the secondary.  Forget about the capacitor and keep it simple.

Once you have a complete set of timing diagrams for the two cases, then look at the waveforms and explain and understand what they mean.  It may sound tedious and like it's a lot of work and it is.

MileHigh