This is taken from Bufon patient 1914 picture. look closely at the output coil. it has two output coil not one and you can clearly see core on top of North and South Electromagnets.

Fine then,if you insist on using a common core you have to perform some tests on it to find out what the lattice structure is. The transition area where the domains flip will have a length spicific to the material for the given length of the core compared to the current and number of windings which creates the field in the core.
  Suspend the core between two coils with cores oriented to attract so the core being tested will have a north end and south end.Use a current equal to the operational current to magnetize the inducers. Find and measure the length of the transition, mark the space on the core being tested.That is the all the space you have to work with for your induced winding. Find the center point of the end areas where you have a length of the core that is north and strong before it begins to flip and do the same for the other side of the core mark them out. That is all the space you have for your inducers. Wire charts will tell you the ratings of the wire and it's capacity, work backwards from what you want as an output that will fit in the space. Take your input source using standard step up or down ratios wind your inducers according to the fact that they each only provide half the output cycle. Assemble the coils on your common core and with a blocking diode on the inducers you should get the DC voltage out or nearly so of the battery voltage you designed it for when you feed an equal to predicted mains power into the output coil there by running it backwards.
If you have it right and can run it with a dc load for a few hours without it overheating then it will do good enough to move on. Hopefully you will just continue on your own.
  Each core material will have differences in the structure of the lattice, even more so for a stacks of laminates.It is not expected to be made perfectly consistent in mass production. If your placing coils blindly on a core you are relying on luck.
  When you run it forward the inducers which is on has to be strong enough to move the bloch wall past the induced coil so it is completely inside the field of the inducer magnets magnetic field when at full power.

Quote from: NRamaswami on March 02, 2014, 05:05:17 PM

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What is the number of turns for a 4 sq mm wire to be wound on a 4 inch dia iron core. soft iron core with greater induction ability. I'm able to hold the electromagnet study at 240 turns by limiting the supply of current to 5 amps in a 2.5 inch dia core. But with 4 inch core, I'm not able to do it. If we use trifilar coil the 32 amps office tripper trips out. If use bifilar coil it takes 18 amps. If we use a single wire I may be able to maintain the electromagnet stable. 4 sq mm wire has 4.91 ohms per 1000 meteres.

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Hi NRamaswami,

I know you addressed your post to Dieter but may I chime in too?
Is my posting here on a possible core material an option to you? http://www.overunity.com/12794/re-inventing-the-wheel-part1-clemente_figuera-the-infinite-energy-machine/msg390270/#msg390270   From your latest post I know  that you have transformer laminations for the core, in this case I ask: you wish to use the I parts from an EI shaped transformer core i.e. you wish to use open and straight cores for the electromagnets in the Figuera setup?

From your given data: 4 sq mm wire,  2.5 inch dia for the core, N=240 turns, I=5Amper from a limiting supply, the AC impedance for your coil could be figured out, so supposing for simplicity a 220V AC input at 5A your input coil must have had about Z=220V/5A = 44 Ohm AC impedance, so this 44 Ohm equals to a Z impedance of sqrt(R²+X_L²) where R is the DC resistance of the coil and X_L is the inductive reactance of the coil. This shows that the DC resistance from the total 44 Ohm impedance is quasi negligible say it was less than 2 Ohm. (of course it can be calculated or simply measured).

Now assuming a 42 Ohm (or so) inductive reactance for your 240 turn coil it means that its inductance at 50 Hz with its core must have been about L=X_L/2Pi*f     i.e.  L=42/6.28*50 = 0.134 Henry.

What I am saying with this kind of 'reverse engineering' your measured data is that it is the AC impedance which would govern the input current for an electromagnet, and you would be able to estimate it in advance by choosing the correct number of turns, the main focus is the number of turns for a given core OD, and to get a stable, sturdy electromagnet the core material is also important: laminated I cores are a good choice.  I do not think that iron rods for the core are a good choice.

I ask what is the size for the I shaped laminations you can have access to? (if it is I shape at all, that is) Starting from the cross section of the I core (I think they are rectangular when bolted together?),  then choosing the length of this I core, an approxamation for the number of turns could be calculated.
I assume you have normal enamelled copper wire with about 2.25 mm outside dia, this gives a 4 sq mm wire cross section.

Gyula

PS I need info how you meant the trifilar (or bifilar) coil? you meant for that case that you used 3 (or 2) wires for the winding and made the coil with them, always guiding the 3 (or 2) wires very close to each other and THEN you connected the 3 (or 2) wires in parallel? i.e. all the start wires into a common point and all the end wires to another common point? 
I assume this because you found the 32 Amper tripper to trip for the trifilar and found 18 Amper input current for a bifilar coil, so if you connected the trifilar or bifilar wires in parallel, then WHY did you do that?
To get higher AC impedance from a trifilar (or bifilar) coil, the windings should be connected in series aiding phase (end of first winding is connected to the start of the second winding, the end of the second winding is connected to the start of the third winding, total coil input will be between the start of the first winding and the end of third winding).

Hi gyulasun:

Thank you so much.. I must admit that your reverse engineering is extremely accurate. Great work and thank you so much.

I used soft iron rods and not the I rods of the transformer laminated cores for that but still your measurements are extremely accurate.

I'm at a point where I can reach success if I'm able to make the electromagnets remain stable. I have earlier used 4 single core wires and taped them together to make a quadfilar coil.

I also have a three core cable of 4 sq mm wires. This has very thick outer insulation. I have two problems.

1. The cable when used gives very high magnetism. When I place between gaps between adjacent turns when winding from top to bottom and then place the winding from bottom to top in these spaces the magnetim is enhanced enormously. But if I wind the cable for more than two layers I suffer a loss. I'm simply unable to understand why it is happening. The cable is 100 meteres long and therefore has 300 meteres of wires.

2. When I used the quadfilar coil made by duct taping four individual 4 sq mm wires magnetism was not high. Actually this was made by duct taping 8x90 meter wires and so it had a length of 720 meters. My memory is that we made two of four primary and two of the four secondary. However I'm not sure on this point as this experiment was conducted between 22 and 30th July 2013. And then they surrounded the secondary wire a single core one and in the middle also we had a single core one. They were all tightly wound without any gaps. Core Magnetism was low. Core was made up of soft iron rods.

3. My simple question is why did the amps consumption was lower earlier at 220 volts and 7 amps and why do the amps consumption very high when we use a highly insulated cable. When we made the two of the three wires primary the third wire was connected to the secondary wires to increase the secondary turns and then it consumed 18 amps.

4. Is there any difference between giving spaces between adjacent wires ( we find the magnetism enormous when we do it) and not giving any space between the adjacent turns. It sure does but why it behaves like this is not known to me.

5. I have I rods of transformers which can be bolted to form the transformers shown by Dieter. They are laminated iron cores but I do not know if they are ferrite. I do not think so as they are very cheap but ferrite I'm told is very costly.

6. I can confirm to you that this Figuera device is not a normal transformer. The only thing that it obeys is this..If the number of turns are increased for secondary, voltage goes up. But conversely from a transformer amperage goes up as the voltage goes up in the secondary. This is what my friends here refuse to believe.

7. Can you please calculate how many turns would be needed to make a 4 sq mm wire with 4.91 ohms dc resistance to remain stable in a 4 inch dia electromagnet. I do not know how to calculate the impedance and do not have the equipment for that.

The wire specifications are given here http://www.finolex.com/images/UserFiles/File/Housegard_PPLeaflet_June%2012_A.pdf

8. I can make the electromagnet 4 inch dia plastic tube dumped with soft iron rods, They normally come to 5 to 6 feet long but I have material to make it as long as 9 to10 feet long in 4 inch dia tubes.

Your calculation is extremely accurate. Great. Thanks a lot. Please oblige. My feeling is that when we placed the quadfilar coil as two bifilar coil, the secondary bifilar opposed the primary bifilar and the additional secondary wires added to the opposing force and so the primary quadfilar only consumed less amperage.. Is this correct? Kind of Lenz law effect only except that the length and number of turns of secondary are higher than the primary. Can you confirm this common sense hunch..I'm obliged.

My I cores are 6 inches long with a gap at the top and bottom and essentially we can only use 4.5 inches of the I core. I do not have the I cores too much. They are number one expensive and number two very sharp and we have to handle then with a lot of care as otherwise they cut the hands. So we have preferred the soft iron rods which are cheap. If the principle is validated then we can go in for better and more expensive material. But until such time we use just soft iron rods. They are not even insulated rods and eddy currents are there significatly.

Only when eddy currents are heavy magnetism is heavy. When we use laminated cores, the magnetism is very low. Eddy currents are also negligible.

Hi Gyulasun:

I apologize that I have not answered the points below..

PS I need info how you meant the trifilar (or bifilar) coil? you meant for that case that you used 3 (or 2) wires for the winding and made the coil with them, always guiding the 3 (or 2) wires very close to each other and THEN you connected the 3 (or 2) wires in parallel? i.e. all the start wires into a common point and all the end wires to another common point? 
I assume this because you found the 32 Amper tripper to trip for the trifilar and found 18 Amper input current for a bifilar coil, so if you connected the trifilar or bifilar wires in parallel, then WHY did you do that?
To get higher AC impedance from a trifilar (or bifilar) coil, the windings should be connected in series aiding phase (end of first winding is connected to the start of the second winding, the end of the second winding is connected to the start of the third winding, total coil input will be between the start of the first winding and the end of third winding).

I have always connected the trifilar or bifilar as follows. End of 1st goes to beginning of second and end of second goes to beginning of third in trifilar coil. The connection is between the beginning of first and end of third.

In bifilar the connection is between the beginning of first wire and end of second wire.

In quadfilar the connection is between the beginnng of first wire and end of fourth wire.

Impedance calculator is given here http://hyperphysics.phy-astr.gsu.edu/hbase/electric/imped.html#c4

But I'm not able to make head or tail out of it.

When measuring resistance in the 2k range the multimeter shows 0.007. How many ohms is that? Is it 7 or 2000x.007=14 ( not possible as the resistance value given for the 1000 metres wires itself is only 4.91 ohms by the manufacturer. So I'm really not able to calculate. But if I'm able to calculate the number of turns needed then I can complete the experiment very quickly.

I have wound so many combinations I now know what works and what does not work. But I do not know the theory or why they work or why they do not work. I simply know what works and then builds it from there.