Confirming the Delayed Lenz Effect

[Farmhand]

Please - as I say on my web-site - don't take my word for anything - please try it yourself.
Yes, what actually occurs with fig 19 seems counter intuitive, which is one of the nice things about it. It begs questions to be asked.

Cheers

Wouldn't it be true to say that once the magnetic field is formed the energy is stored not so much in the coil's wire that created it but within the magnetic field itself ?
And then when the magnetic field collapses it's energy can discharge through the second winding and into the battery.

That's the regular way to do it, we can even use a FWBR on the second winding, (which in a Bedini setup or one with a trigger coil would be the third winding)
which the Bedini people call a trifilar setup. It can use a single rectifier or a FWBR.

The point is the magnetic field discharges into the lesser resistance by preference, because the emf from the magnetic field collapse produces current through the lesser resistance first. If the load coil is open then bingo transistor is hit with coil discharge energy in total. Same thing happens if the charge battery is very badly sulfated.

Hoptoad is correct as I see it. I agree try it and see. I like to say that too. 

P.S. I admit I did not look very well at the drawing.

I can't find the link, is there a link to a circuit drawing or the "pages" ? Please.


Cheers

[ALVARO_CS]

Farmhand:
Here`s the link: http://www.totallyamped.net/adams/index.html

the No19 schematic is in page 6 with a full explanation.
I have used that setup in many experiments with voltages from 4.5 to 12 V at 500mA max.
May be I was lucky or may be it works as said, unfortunately, I cannot show accurate measurements,
as I have got poor equipment. (and very low economic means, but very high spirits).

Hoptoad:
Thanks for your answers, and thanks for those pages, which have been of invaluable help in my learning process.
cheers

[hoptoad]

Wouldn't it be true to say that once the magnetic field is formed the energy is stored not so much in the coil's wire that created it but within the magnetic field itself ?
And then when the magnetic field collapses it's energy can discharge through the second winding and into the battery.

snip...

Exactly.       KneeDeep

Cheers

P.S. Exactly the sort of question the circuit begs asking. Sometimes the answer to a question is so obvious the question is never asked.
But, alas, all too often we forget or simply overlook the obvious.

[gyulasun]

Other MOSFETS:

I switched to the AUIRF9Z34N (P-Channel) and the AUIRFZ34N (N-Channel) because they have less resistance when switched on. This produces a little bit higher rpm value (about 10%) for the same power input. Theire 55 V Drain to Source braekdown Voltage is high enough because the drive coil is switched (commutated) cleanly, only small spikes.

Greetings, Conrad

Hi Conrad,

You have very nicely solved the control of the H-bridge by a single Hall sensor instead of the two, using complementary MOSFETs, congratulations.

Would like to suggest two things.

One is using a diode D in series with the positive supply rail going to the H-bridge and connecting a puffer capacitor C across the supply rails of the H-bridge. (I modified your original schematic to show what I mean.) The reason for these small modifications is that the collapsing field of the coil in your original schematic goes back to the power supply and most probably dissipates across its inner resistance but inserting a diode prevents the 'flyback' pulse seeing the power supply and can only go into the puffer capacitor.

The second suggestion would be (after testing the first one) to use Schottky diodes in parallel with the built-in body diodes of all the 4 MOSFETs, (one diode for each MOSFET). The reason is that the spikes from the collapsing fields are steered automatically into the puffer capacitor from both switching phases of the H-bridge (in your original schematic this is also inherently available of course except that it is steered onto the supply rails).
The body diodes when conduct normally have a forward voltage drop very close to 0.55-0.6V as minimum drop, so shunting them with diodes of less forward drop feature increases the captured energy. (Even fast recovery Si diodes like UF4002 etc can help as a start to check this if there are no four Schottky diodes at hand.) By the way you can check the body diodes forward drop by digital multimeter's built-in diode test feature if there is such, just remove the coil and supply rails from the FET bridge. With this feature you can see the resulting forward drop when paralleling an outside diode with the body diode, albeit at about 1mA forward current level only what most diode testers provide. (Obviously, anode goes to anode, cathode goes to cathode when paralleling.)

What else could be done to improve your setup?  I already referred to a few pages back to utilize both poles of the electromagnet, unfortunately this is not a simple task. And also, the use of coils with much much less DC resistance to minimize copper loss. This latter can involve the possibility of reducing the supply voltage to the bridge.
Also, I think it might be worth somehow reduce the 50% duty cycle which now inherently comes from the diametrically magnetized ring magnet. However, to achieve lower duty cycle in your present setup, you would have to make a separate disk onto the rotor axle with small disk magnets and fix the Hall (or Halls) over them.  This way the duration of the attract-in and the repel-out phases could be controlled more precisely (if needed).

rgds,
Gyula

[conradelektro]

@Gyula: thank you for the many suggestions, I will test them.

My set up still has some mechanical problems (in spite of the new brass axle). The ball bearings make some strange noise, may be I damaged them a bit during mounting. Now it also became evident that the ring magnet is not balanced. Up to 4000 rpm the vibrations are minor, at the peak rpm of 8400 the noise scares me because everything could fly apart.

But for the moment I leave everything as it is (besides the diodes and the buffer capacitor as suggested by Gyula). I want to try to generated some power with "strange coils".

Please note the rather low "input power" requirements and we will see how much "output power" various strange "allegedly Lenz free" coils will produce.

Greetings, Conrad