Spark-gap + Step-down-transformer = OU?

[broli]

Just analyze the equations carefully. And look at the raw parameters that make up the inductance of a solenoid. For instance I just noticed we completely ignored coil length so far. If you have two coils on top of each other, with the same amount of windings but one longer than the other. When energizing the short one and opening the switch and letting the long one collect the inductive energy what you did is instantly and effortlessly double the length, this would halve the flux, so conservation of flux kicks in and doubles current. Since inductive energy is linearly proportional to 1/length as well you should see an increase.

[nilrehob]

You're right. Then one solution would be using thicker wire for the secondary and keep the same number of turns (but not wind them together).
So which part of the kapagen do You think we are looking at?

/Hob

[broli]

You're right. Then one solution would be using thicker wire for the secondary and keep the same number of turns (but not wind them together).
So which part of the kapagen do You think we are looking at?

/Hob

That's an interesting last sentence but I don't want to go into the kapagen here as it has enough threads and imo would just dilute the logical train of thoughts this thread started with.

The trick is to try and trap as much flux as possible. That's why a closed loop core like a toroid could be beneficial. It's well known that spacing of the windings of the toroids affects the inductance significantly:

http://users.catchnet.com.au/~rjandu...s/wind_deg.gif

I would suppose the bigger the toroid the more you can space the windings apart and increase the flux difference. If we suppose most of the flux gets trapped. Then switching from a densely wound winding to a spaced out one, will give maximum flux difference and thus shoot the current up to conserve it. This all without changing the amount of windings. So inductive energy has to go up too.

[nilrehob]

Great pic of the toroid, thanks!

But I must admit there is still an enigma left in the formulas for me.
We have the definition of the unit Henry:

Which gives you Wb=H*A, or Φ=L*I, right?
Then we have the definition of flux:

Combine them and you get L=μ*N*A/l
But that's not right! It should be

Where is the error?



/Hob

[broli]

Great pic of the toroid, thanks!

But I must admit there is still an enigma left in the formulas for me.
We have the definition of the unit Henry:

Which gives you Wb=H*A, or Φ=L*I, right?
Then we have the definition of flux:

Combine them and you get L=μ*N*A/l
But that's not right! It should be

Where is the error?



/Hob

flux is not Φ=L*I but it is Φ=L*I/N. Amount of turns has no unit. The reason why you need to divide by N is because the inductance already has amount of windings squared (N^2) incorporated.
It's easier to see this if you derive the "inductance" from Faraday's law (which is where it comes from in the first place):

[nilrehob]

Yes, I just found it myself
L = N × d Φ / d I
at Magnetism: quantities, units and relationships

/Hob

[nilrehob]

Now, back to your toroid-pic:

This reminds me very much of the toroid in the vid starting this thread:
http://www.energeticforum.com/renewa...gy/6665-a.html

/Hob

[nilrehob]

So what about three parallel windings,
each occupying 120deg of the toroid and having N turns each for input,
and then a wider and thicker winding with N turns on top (or under?) as output?
But on the other hand, parallel windings lower the inductance ...

I have to dig up the Bob Boyce documents lying on my hard-drive somewhere.

/Hob

[broli]

So what about three parallel windings,
each occupying 120deg of the toroid and having N turns each for input,
and then a wider and thicker winding with N turns on top (or under?) as output?

I have to dig up the Bob Boyce documents lying on my hard-drive somewhere.

/Hob

I would wind each consequent winding next to the previous, so basically like a bifilair, trifilair... coil. This in order that 10 windings of the "bigger spaced" coil covers as much area and leaves no gaps without having to actually use a real broad wire. While your input coil has 10 windings which are spaced very closely. This also brings us to a more accurate flux equation for a toroid:




theta*r is really just definition of arc length. In textbooks theta is always equal to 2pi radians which is 360°.

[Farmhand]

Tesla Toroid

Hi nilrehob and broli, Good to see you guys doing the math on this, the more people that look into this the better. I thought I would give you guys this link to look at. If you look at page 110 figure 92 and 93, also page 111 figure 94.

Page 110 figure 92 and 93 is the Tesla transformer/converter and page 111 figure 94 is the same thing with generator attached. The section "High Frequency Polyphase Transformer" starts on page 109, it's very interesting, in my opinion it can be a "flux flywheel generator" and that is kinda how it's descibed in there.

Tesla used quad primaries with the oposite pairs series connected and fired 90 degrees out of phase, which was actually 180 out of phase on the generator.

I think, maybe you guys can decifer that better than me. He also used quad secondaries and he shows that the secondaries can be connected however is needed or desired, it's a very cool setup. And he also used iron shielding wire aswell sometimes.

The inventions, researches and writings of Nikola Tesla, with special reference to his work in polyphase currents and high potential lighting : Martin, Thomas Commerford, 1856-1924 : Free Download & Streaming : Internet Archive

Enjoy
Cheers

[nilrehob]

But on the other hand, parallel windings lower the inductance ...

On third thought, parallel windings on the same core doesn't affect inductance, just resistance, right?

/Hob

[nilrehob]

I would wind each consequent winding next to the previous, so basically like a bifilair, trifilair... coil. This in order that 10 windings of the "bigger spaced" coil covers as much area and leaves no gaps without having to actually use a real broad wire. While your input coil has 10 windings which are spaced very closely. This also brings us to a more accurate flux equation for a toroid:




theta*r is really just definition of arc length. In textbooks theta is always equal to 2pi radians which is 360°.

This is getting so interesting i might just get myself a big fat toroid core, at last!

So it all boils down to a theoretical COP=θin/θout, right?

/Hob

[broli]

On third thought, parallel windings on the same core doesn't affect inductance, just resistance, right?

/Hob

Correct, and it's a way to have a "thicker" wire like you mentioned earlier without really having to use a thicker wire.

[nilrehob]

So it all boils down to a theoretical COP=θout/θin, right?

Edit: since θout is always 2π COP is proportional to 1/θin, or just 1/θ for short.

/Hob

[broli]

So it all boils down to a theoretical COP=θin/θout, right?

/Hob

In absolute theoretical cases. But I doubt it be as significant as that in practice. But it's a rather simple experiment. You can compare inductive energy like you did before by converting it to electrical in a cap. 2 Setups:

Primary small angled coil energized and then letting it discharge into a cap. Then same experiment but this time you put the cap on the big angled coil. And hopefully you'll see more voltage there in the cap.

The other experiment needs you to energy both coils in series and discharge them in series, and comparing it to only opening the switch on the small angled coil and discharging through the second in the same cap.