### Author Topic: WFC VIC  (Read 125824 times)

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##### Re: WFC VIC
« Reply #208 on: March 06, 2011, 13:17:22 pm »
Hi kalli,

The charging choke 56 in series with the diode assure that the voltage is not limited to 60v... actually if you think about actually one of the chokes is subtracting the field... So he basically is applying 20v + 20 of the choke in series with the diode, than the other tube is receiving 20v max also per pulse.

During the resonance energy will be accumulated in the vic, i can tell you maybe more than 1000 times more energy than the input can be developed there, for sure, the electrical resonance means recirculation of energy. So the "tuned" choke could actually achieve thousands of volts in my though if closed the circuit resonance with the ground capacitance relation to the cell.

The smaller the capacitance the greater is the Q so with less amps you get higher voltage per amp circulating.

HE could have worked with values like 50pf witch for a big choke still give us a relatively high Q resonance in real world.

I'm going for 330pf with my cell (measured value)... Between my tubes i might have 1,8 nf but i can only measure the resistance, i already achieved 10kohms of resistance. This means that 1 amp passing thru it would develop 10kv.

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##### Re: WFC VIC
« Reply #209 on: March 06, 2011, 14:07:12 pm »
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The charging choke 56 in series with the diode assure that the voltage is not limited to 60v... actually if you think about actually one of the chokes is subtracting the field... So he basically is applying 20v + 20 of the choke in series with the diode, than the other tube is receiving 20v max also per pulse.
I see it simply like that. You have three coils on a core, all the same. Two of them are opposing each other. So the final relevant voltage for your diode is the voltage of one coil. And this voltage cannot exceed 600volts. And as all your coils are on the same core, each coil is limited to these 600volts. Not one coil can go higher. For if it would go higher, it would act like a primary for the other coils, which would then also get a that high voltage, as all have the same amounts of turns.
There's a massive difference happening if you put all coils on the same core, than if you have them separately. You just cannot separate their fields.
This is the reason, why I first thought the SS wire is needed. For it would allow the coils to have more unshared field lines...

But as we see from the 5-VIC-coil, this is obviously not needed. This VIC worked, and it worked just with all coils copper and on the same core...
IMHO there would be only two configurations, which would allow it otherwise. One would be, if the core goes into saturation. Then the coils would become independent of each other, and the voltage could go high, without affecting the diode.
The other would be, if one coil has massively more resistance than the others. This coil would have more "internal" voltage drop than the others. So the there would have to be two opposing coils and one coil with more internal resistance. Then you could go higher with the voltage of the opposing coils, without affecting the diode.

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During the resonance energy will be accumulated in the vic, i can tell you maybe more than 1000 times more energy
I don't think this is a realistic Q value for this kind of circuit with a core. The core losses are IMHO just too high. Just look at the datasheet of any core and at it's indicated core losses. And you also have to remember the distributed capacity of a coil. This is far bigger than 50pF. This is why Tesla used to wire his magnifier coils with big distances between each winding (although this reduces the L). For, as he said, otherwise the capacity is just becoming too big, to get a high Q.
At least one thing is for sure: The coils in the 5-coil-VIC, that Stan used, certainly had quite a high distributed capacity, as they were "normally" wound with 3000 turns. I would say, that this capacity strongly dominates the resonance circuit. And also my experiments actually tend to show, that these are the important capacities...
« Last Edit: March 06, 2011, 14:44:05 pm by Kali_ma_Amar »

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##### Re: WFC VIC
« Reply #210 on: March 06, 2011, 16:22:44 pm »
The 220 ohm resistors were like I said wired across the primary coil(parallel).A friend had talked with a coil manufacture,and they told him that 10.5 ohms coil would get hot,then he asked them what would happen if you were to wire a 220 ohm resistor across it,and he stated that it would run cooler.Not my words.

As for the NVR1550 diode,there is actually a MUR1550 and a MUR1560.The first is a 500 volt,and the second was a 600 volt.

Kali,as for your explaination of the voltage step up up 1:5 with 12 volts in and 60 volts out was a little confusing.But I believe I understand what you were getting at.

You are stating that if you apply 12 volts to the primary coil,with a step up ratio of 1:5 you will then get 60 volts out to the blocking diode.Now in my testing of my coils,I have a step up ratio of 1:10 or as I would put it 10:1.So if I apply 12 volts to my primary I should get 120 volts out of the secondary.Right?

Well when I test the output of my secondary without any load on it,I get a much greater step up than 10:1.I've seen several hundred volts.No just maybe that is what Stan is hoping for with his set up.Maybe because we are restricting amps with the choke coils that this high voltage from our secondary is able to stay high,because of the very low load.

Under normal step up coils we are appling loads to the secondary output which pulls the voltage down to the actual ratio of the steup.So just maybe with the chokes restricting the amps,we are able to keep this higher voltage than the stepup ratio produces.Maybe it has something to do with the coils all being on the same core that allows  this greater voltage to be produce.

Now again with my coil set up,of 100 turns primary,1000 turns secondary,and 2000 turns chokes,I have seen between 1kv-2kv at the cell.It it hasn't had any ill effect on the blocking diode.And my diode is the same rating as a MUR1560.

Thats some of my thoughts on this matter as I have seen it with my own testing.
Don

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##### Re: WFC VIC
« Reply #211 on: March 06, 2011, 17:00:29 pm »
Really across it??? So how did you measure the primary resistance, if there were resistors in parallel? For that you would have needed to open the circuit. Or did you calculate it? Or how did you do that?

If you get a higher voltage, than your step-up ratio, then you're either using it on a resonance, or you get a surge from the stray-inductance, or you are using it as a flyback. What does your scope say, when you just put a rectangular waveform on your primary and no load on the secondary? It should output also a rectangular waveform with exactly the step-up ratio. Maybe in the beginning of the rectangular you see a short spike (stray inductance) with some ringing afterwards.  OK, maybe Stan used these switching surges, who knows...

Really? You have a 600PIV diode which withstands 2kv. I'm quite impressed. The only reason for this I could image is the very low energy oscillating, so that the diode capacity can handle this, but then the diode would be quite useless...

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##### Re: WFC VIC
« Reply #212 on: March 06, 2011, 18:27:53 pm »
The primary coil was measured with the resistors removed.All coils were measured unconnected from the rest.
All of my voltage measurements were taken at resonance.When pulsing the primary coil with square waves,you get sine waves as an output of the secondary.I would have to retest to see if the step up ratio shows up.
Don

Update:
I just tested my coil setup and this is what I came up with,

100 turns primary,  1000 turns secondary
12 volts dc applied to primary

Now I performed two test,one without bifiller choke coils on core (not connected to anything)and the other with chokes off core,then tuned to resonance with scope.

First test without chokes showed @ 120 volts out of secondary, just hooked to scope leads, and resonance was at 57 khz.This gives you a 10:1 stepup.

Second test with bifiller chokes on core and not connected to anything, gave @ 250 volts out of secondary,just hooked to scope leads, and the resonance was at 32.8 khz. This gave a stepup of 20:1.

So there is something happening with all coils on the core.It doubled the voltage out of the secondary.

Don

« Last Edit: March 06, 2011, 19:25:53 pm by Dynodon »

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##### Re: WFC VIC
« Reply #213 on: March 06, 2011, 19:27:51 pm »
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The primary coil was measured with the resistors removed.All coils were measured unconnected from the rest.

Wow, didn't think that you were that invasive during your "visit", to even take things apart. But if I would have had the possibility, I would've certainly done the same.
I really think it is quite strange to wire resistors in parallel (at least at 12volts, this means a loss of 2watts, so no wonder he used bigger resistors here). This would only beware the coil from heat, if the current through the transistor is limited. But this doesn't really make sense, due to several reasons. First, you could have just fed the transistor with another base current, to get less current through the primary. Second, as the resistance of the primary is that low, compared to the resistors, still almost all the current would flow through the primary.
IMHO it only does make one sense. As I already stated before, it would be like a replacement for the freewheeling diode. But these resistors would (instead of the diode) allow quite a voltage to develop across the primary (but on the other hand they would also limit the maximum voltage, compared to nothing in parallel). So the circuit would act like a flyback. All in all, this wouldn't astonish me, if we look at how the VIC was made. But what puzzles me, is that the TIP120 can only withstand 60 volts.
If we look at how he wired the VIC, then it actually is rather a flyback circuit. Why? The secondary has only half the voltage of the 2 chokes in series. So the diode would be blocking, while the primary is on. When the primary is off, the diode would be conducting, as the 2 chokes have double the voltage than the secondary. So it would make sense, to have the primary in a flyback manner. But the TIP120 is only for 60volts, which is really not much for a primary flyback voltage (only 4 times voltage step-up would be possible, to a total of 4x5=20 step-up ratio from 12volts). And without any additional circuitry to help the TIP, it would live very dangerously (especially in a resonance condition).
Sure if you do it like that you could have higher voltages than you PIV diode rating. But only in one way. Which means, the resonating voltage in the other direction would always have to be smaller. For this, the flyback energy surge has to go somewhere. The best candidate for this: The WFC.
So it could maybe really be like this: The coils resonating, and every half wave, quite a surge is going through the circuit (when the primary is off). The good thing is, during this surge, the voltage could go as high as you like, the diode PIV isn't relevant here, as the diode is conducting. But two things would limit your maximum attainable voltage: First, the resistance of your circuit (the higher the resistance, the higher the voltage) and second, the primary transistor. If there would have been a different transistor, I would say, everything matches. But 60volts!?!
If you do not protect the transistor with an additional circuitry (like the freewheeling diode), then this simply means, that the reverse voltage on your coils is not allowed to go beyond (60-12)volts*5=240volts, which is really not much...So I'm puzzled???

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All of my voltage measurements were taken at resonance.
As I said, at resonance you certainly get a completely different picture and aren't anymore only limited by the step-up ratio, but get an extension by the q-factor.

Edit:
@Don: You're sure the 57KHz is the basic resonance frequency of your coil, and not some harmonic? For actually. Under no load condition, in resonance, already with a step up of 1:10, you should get mucha higher voltage than just 10 times more. How are you driving your circuit? With a FET? Do you have the additional series diode?
« Last Edit: March 06, 2011, 20:05:55 pm by Kali_ma_Amar »

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##### Re: WFC VIC
« Reply #214 on: March 06, 2011, 19:53:27 pm »
Kali, Don did those tests on his own coil, not Stans.

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##### Re: WFC VIC
« Reply #215 on: March 06, 2011, 20:08:57 pm »
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Kali, Don did those tests on his own coil, not Stans.

lol, yeah, I know. But we were mainly talking about the resistors in Stans original VIC.

Additional thought: As two coils are opposing and have the same size, you could as well say, that you can take both of them away. Then you would just have one coil in a flyback circuit, which should do the same. So why are the 2 additional coils there? Everything can resonate. And as I have seen, from my experiments, the coils are able to resonate some AC through the WFC. So it would be now, like having some AC resonating though your WFC with some unipolar bangs everytime, the primary switches off. But as I said, this could only be, if the primary transistor could withstand more voltage...This really puzzles me...And it would also not really match the descriptions given by Stan...