Originally posted by nilrehob
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Spark-gap + Step-down-transformer = OU?
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Also would like to mention. I think the area of the core is also safe to use as the switching parameter. If you use the same current and amount of turn, decreasing area will result in a proportionally equal decrease in flux and inductance The problem was how do you adjust area without loosing flux? In a moment I'll post how, unless I realize a mistake. But to be honest it's really simple so you might figure it out before I'm back. Think again closed loop.
Edit: Here's the basic idea:
http://img191.imageshack.us/img191/1753/encconf2.jpg
When the upper coil is switched off and flux is conserved the lower coil has to increase current flow. Since current is squared and area is just linear, energy increase should happen.
This can even be combined with the length of the coil to multiply the increase of energy:
http://img522.imageshack.us/img522/7746/encconf3.jpg
Length is increased and Area is decreased. Both are linear too in energy equation. These changes will both reflect on the squared final current.Last edited by broli; 01-11-2011, 08:36 PM.
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Originally posted by 7imix View PostLast edited by broli; 01-12-2011, 08:48 AM.
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Originally posted by broli View PostAlso would like to mention. I think the area of the core is also safe to use as the switching parameter. If you use the same current and amount of turn, decreasing area will result in a proportionally equal decrease in flux and inductance The problem was how do you adjust area without loosing flux? In a moment I'll post how, unless I realize a mistake. But to be honest it's really simple so you might figure it out before I'm back. Think again closed loop.
Edit: Here's the basic idea:
http://img191.imageshack.us/img191/1753/encconf2.jpg
When the upper coil is switched off and flux is conserved the lower coil has to increase current flow. Since current is squared and area is just linear, energy increase should happen.
This can even be combined with the length of the coil to multiply the increase of energy:
http://img522.imageshack.us/img522/7746/encconf3.jpg
Length is increased and Area is decreased. Both are linear too in energy equation. These changes will both reflect on the squared final current.
I'm not prepared to carve in the core any day soon but I might try to add a coating to one side of the ring if all other experiments fail.
/HobHob Nilre
http://www.youtube.com/nilrehob
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Originally posted by nilrehob View PostI was afraid this would be Your solution
I'm not prepared to carve in the core any day soon but I might try to add a coating to one side of the ring if all other experiments fail.
/Hob
http://img259.imageshack.us/img259/5442/compa1.png
That setup uses same number of turns as current on both coils. The real strange part about that is the fact the programs induction calculator gives an almost exact ratio match of areas. For instance if areas are 10:1 then inductance is 10:1 between the two setups.Last edited by broli; 01-12-2011, 09:42 AM.
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Originally posted by broli View PostI would wait with that as the simulation is giving some unintuitive results.
http://img259.imageshack.us/img259/5442/compa1.png
That setup uses same number of turns as current on both coils. The real strange part about that is the fact the programs induction calculator gives an almost exact ratio match of areas. For instance if areas are 10:1 then inductance is 10:1 between the two setups.
/HobHob Nilre
http://www.youtube.com/nilrehob
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Originally posted by nilrehob View PostI must be missing the point as It seems to be the result we are looking for?
/Hob
When keeping turns and amperage constant you should have the same field density with any sized area. That's why 1T becomes 10T at the small leg. But why isn't it 1T at the small leg if we energize that coil. Instead it also shows 10T.
Basically the simulator is contradicting itself by giving us an inductance that doesn't match the simulated field result. It should have kept the inductance the same to match the simulated field. Now it's showing as that two coils with the same current, turns and overall same field distribution in a core give two different inductances.
If this is truly reality we still win. We could just flip the roles by making the small leg the input and large leg the output. But I would have liked it more if it showed what was predicted, lol.
Btw I used vizimag, has a trial version too.Last edited by broli; 01-12-2011, 10:24 AM.
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Originally posted by broli View PostThat the inductance would decrease yes. But why isn't the simulation showing proper field strengths? Or am I seeing something wrong.
When keeping turns and amperage constant you should have the same field density with any sized area. That's why 1T becomes 10T at the small leg. But why isn't it 1T at the small leg if we energize that coil. Instead it also shows 10T.
Basically the simulator is contradicting itself by giving us an inductance that doesn't match the simulated field result. It should have kept the inductance the same to match the simulated field. Now it's showing as that two coils with the same current, turns and overall same field distribution in a core give two different inductances.
If this is truly reality we still win. We could just flip the roles by making the small leg the input and large leg the output. But I would have liked it more if it showed what was predicted, lol.
Btw I used vizimag, has a trial version too.
Φ is measured in Wb and T=Wb/m²
So while Tesla change with area, Weber stays the same.
Or is it something else?
/HobHob Nilre
http://www.youtube.com/nilrehob
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Originally posted by broli View PostIf you have a scope just look at maximum voltage amplitude of the secondary for a certain cap, and redo the experiment without hooking the secondary, by just putting a cap across primary and opening the main switch to let it oscillate to measure again maximum voltage amplitude. If you don't have a triggerable scope you need to do the switching through a circuit in order to get a periodic pulse. Even if energy is doubled, voltage in the cap should at best be 1.4x (sqrt(2)) more in secondary compared to primary only.
Also when the cap is across the primary the battery will charge it directly... So it's not really a fair comparison...
Anyway, very interesting, I have a feeling there really is something to discover here.
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Originally posted by 7imix View PostThanks, that was an interesting experiment. However, the manual switch doesn't give me enough control over the duration of the pulse, which is the most important factor. I was able to get large spikes and small spikes off both the primary and secondary but didn't have any control over reproducing them. Next I am going to hook one of my impulser circuits up to this to try to get more controlled results.
Also when the cap is across the primary the battery will charge it directly... So it's not really a fair comparison...
Anyway, very interesting, I have a feeling there really is something to discover here.
I wish my toroid would get here soon.
Nice oscilloscope you got there, small and handy.
/HobHob Nilre
http://www.youtube.com/nilrehob
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Originally posted by nilrehob View PostGreat that you are experimenting on this!
I wish my toroid would get here soon.
Nice oscilloscope you got there, small and handy.
/Hob
I pulled that toroid out of something from the thrift store a while back... Can't remember what it was from though. It was just sitting there waiting for this project for months.
The scope is the dso nano, it is incredibly handy, but I am definitely reaching it's limits. I'm broke at the moment though, so it will have to do for now.
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Originally posted by 7imix View PostThanks, that was an interesting experiment. However, the manual switch doesn't give me enough control over the duration of the pulse, which is the most important factor. I was able to get large spikes and small spikes off both the primary and secondary but didn't have any control over reproducing them. Next I am going to hook one of my impulser circuits up to this to try to get more controlled results.
Also when the cap is across the primary the battery will charge it directly... So it's not really a fair comparison...
Anyway, very interesting, I have a feeling there really is something to discover here.
As for the dc bias. It's simply a matter of subtracting it from the measured cap voltage.
Also since you have a DSO pulsing it shouldn't be required. Have it set on rising edge trigger and put it across the cap. Then open the switch and it should capture the voltage ringing down, then just measure the highest peak of voltage.
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Originally posted by broli View PostAll experiments should be done with one cap preferably. Don't measure open circuit voltages. As this would give you little information. Make sure the capacitance isn't too small in order to prevent high frequency parasitic effects.
As for the dc bias. It's simply a matter of subtracting it from the measured cap voltage.
Also since you have a DSO pulsing it shouldn't be required. Have it set on rising edge trigger and put it across the cap. Then open the switch and it should capture the voltage ringing down, then just measure the highest peak of voltage.
Ok, will subtract the dc offset.
The shot you see in the pic is the result of opening the circuit with a trigger set. I was using a falling trigger to capture the cliff seen and avoid triggering on the positive going spike from closing the circuit. It was almost impossible to get reproducible values though, each run of the experiment would give wildly different output depending on the pulse duration. I think the nano's trigger is buggy too, or the nano just doesn't have a high enough sample rate to reliably trigger all the time. I had to keep trying again and again and many presses didn't trigger.
I will make a video tomorrow and experiment some more so hopefully I can get some consistent results...
Thanks!
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