Sharing ideas on how to make a more efficent motor using Flyback (MODERATED)

[MileHigh]

Are you absolutely sure there is no possibilities of an increase in inductance when approaching a magnet to these kind of cores?

Luc

The whole point of that Steorn toroidal coil + core configuration was to be impervious to the effects of external magnetic fields and have a near-net-zero production of EMF from changing external magnetic fields.  I am not absolutely sure in the sense that you may be able to intentionally set up something that increases the inductance.  But then that is just loading the dice, right?  In a generic sense for a magnet approaching that toroidal coil + core configuration I can't see the inductance increasing.

What I am absolutely sure of is that that clip demonstrates a big honking vibratory motor powered by the pulsing toroidal coil + core.  When the current is off, there is attraction and the magnet gets pulled in.  When the current is switched on there is no attraction and the magnet goes back.  The tape/tire acts as a lossy elastic material that pulls on the magnet to keep it in place.  The bottom line is that the magnet does not vibrate for free, the power to make it vibrate comes from the coil and in the clip there is a direct correlation between the vibrating and the slower rise time of the current.  I am willing to bet you if the experiment was repeated but this time when the magnet was brought closer to the coil it did not vibrate at all, then the observed current waveform would not change or it would rise slightly faster.  It was a big honking motor effect and JLN was not aware of it.

[gotoluc]

In a generic sense for a magnet approaching that toroidal coil + core configuration I can't see the inductance increasing.

Okay, here is a generic test done by me demonstrating an increase of Inductance when approaching a magnet to a coil wound on a Finmet toroid core.

If you pulse a coil on a Finemet toroid and approaches a magnet the result will be a decease of current just as JLN  and myself have demonstrated.

Link to my demo done back in 2011: https://www.youtube.com/watch?v=_cCYKChCFqk

Regards

Luc

[tinman]

Well, thats the problem with words, they can be explained differently as one had originally intended, if not selected carefully, like in this case.

What i was trying to say was that it looks like the magnets (fields) are inducing this "negative-induced voltage in series with the battery voltage"
against the power needed to drive the coil.


Itsu

So at that instance, this "negative-induced voltage" seems stronger then the driving power for the rotor (otherwise we would not "see" the effects
of this "negative-induced voltage"), but it does not mean that "the rotor seems to be putting more energy back into the system than it takes to run it"

As i said before,there is no work being done by the rotor during this !negative voltage! stage,as the circuit is open,and voltage alone is not power--as we are told often,and no power means no work being done. As the transistor or mosfet closes,then the voltage across the coil instantly becomes the same as the voltage across the supply battery--as your own test showed Itsu. With or without the rotor,the voltage across the coil remains the same during the on time.

What needs to be looked at is what can the induced magnetic field do to or change in that inductor as a whole that would lower the current required to maintain that voltage across the coil during the on time. Well one thing would be that some how(and i dont see how),the PM's field is raising the resistance of the coil,and so less current would be required to obtain the voltage across the coil-or the fact that the magnetic domains have already become some what aligned by the PM before current starts to flow through the coil. It take energy to align the domains within the core,and at the same time eddy currents are produced within the core. Without the rotor,this energy comes from your supply source,and with the rotor in place,some of this energy comes from the rotor in stead,and so less is required from the source.

Some times in life you have to make hard choices,and this is one of those times.
What i mean by this is,you now have to either believe in what you see on your bench,and work it out for your self--or you choose to believe in those that you deem apt in the art of  EEing.
I guess it's time to weigh up all the info and results presented on both sides of the fence,and start putting them into perspective,and start asking yourself questions-like
1-how can the rotor in some way reduce the P/in by more than is required to drive it in the first place?
2-How can the open circuit voltage across the battery/coil combo reduce the P/in,when the voltage across the coil remains the same with and without the rotor in play?
3- Why dose Poynts sim not show the same effect as we see with our DUT's-in that while he can show a reduction in P/in,he also gets a reduction in P/out,where as we get a reduction in P/in while maintaining or increasing the P/out when the rotor is in play. What is the one thing his sim dose not have that we do have?.
4- Why has no EE to date been able to recreate the effect without the use of PM's ?.
5- Is the inductance of the coil increasing or decreasing as the PM approaches it. This needs to be thought about very carfully,and what is taking place as the coil is switched on. The coil creates one pole at the end of the rotor,and the approaching magnet on the rotor is of the opposite pole. So is the core going to see an increase of magnetic flux at the rotor end,or a decrease-->remember,the coil has produced a magnetic field of one polarity,and the PM approaching it is of the opposite magnetic polarity. Also-will a coil with less inductance draw more current during that pulse,or less current during that pulse to that of the same coil that has a higher inductance value?.

Added
Here is something that MH wrote a few post back
Quote: No, if anything, the presence of an external magnetic field should interfere with the core material's normal domain flipping and effectively reduce the inductance and therefore make the current waveform rise more quickly.

It is interesting that we see the opposite to that,in where the current waveform rises slower when the rotor is in play.


Things to think about.

Brad

[tinman]

Okay, here is a generic test done by me demonstrating an increase of Inductance when approaching a magnet to a coil wound on a Finmet toroid core.

If you pulse a coil on a Finemet toroid and approaches a magnet the result will be a decease of current just as JLN  and myself have demonstrated.

Link to my demo done back in 2011: https://www.youtube.com/watch?v=_cCYKChCFqk

Regards

Luc

Great demo Luc,and once again seems to show the opposite to what the EE guys say should happen. I will have to give this a go myself today,but use a ferrite toroid to see if the effect is the same.

Brad

[MileHigh]

Okay, here is a generic test done by me demonstrating an increase of Inductance when approaching a magnet to a coil wound on a Finmet toroid core.

If you pulse a coil on a Finemet toroid and approaches a magnet the result will be a decease of current just as JLN  and myself have demonstrated.

Link to my demo done back in 2011: https://www.youtube.com/watch?v=_cCYKChCFqk

Regards

Luc

I looked at your clip and it does appear that the inductance is increasing with the addition of the magnet.  However, it's highly unlikely that what you did in that test is directly comparable to the JLN test.  I don't get a sense that there is any motoring action in your clip, but it is a possibility.

So, motoring action will slow down the increasing current in a coil, which on the surface appears to look like increasing electrical inductance, but it's not really.  If anything, you can say that through the motoring action you have coupled to a mechanical inductor (the mass of the magnet) to the electrical inductor.  A mass in motion has the exact properties of inductance.

You apparently demonstrated increasing inductance wile adding a cylindrical magnet directly to the center axis of the toroid.  This is not directly comparable to the JLN clip.  The lesson is that you can't do one experiment and then apply the results of that experiment with a wide brush to all other situations.

In your clip, you need a schematic to allow people to make sense of what your scope display is showing.  I even made that comment on your clip in 2011.  What you are calling the back spike looks more like a damped LC resonance.  When you add the magnet, the frequency of the LC resonance decreases, which also supports the increasing inductance claim.  I hope that you learned from Verpies that going forward you need a schematic 100% of the time, no matter how simple the circuit is.

MileHigh