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EvilTesla-RG

Mon Sept 14 2009, 01:23AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Hey,

Every once and awhild, my subconsious bothers me to build and desing a new type of tesla coil. The last time, I came close to some usefull ideas, but I couldn't pin the idea down well enough to put it on paper.

However, recently, I have seen an interesting idea that has once again sparked my imagination.

Please bear with me, as I have only built two SGTC's. I lack the knowledge to build even the simplist SSTC.

This interesting idea that I have come across, is a transformerless Tesla Coil.

here is the page:

more importantly, here is a schematic of a special coil that this person has built

Mres6

I find it an interesting idea, but with no significant advantages over a basic SGTC.

So, let me speculate a bit, at the risk of making some grivouse electic error.

First, for the sake of simplicity, take the above diagram, and remove L2 and C2. Let's keep this simple, and keep it ONLY dual resonate.

Next, C3 to simply be a torriod. (As I think was inteanded by the diagram, but wasn't comunicated well).

Now we have a normal SGTC, but with the secondary directly coupled to the primary.

I have heard of this done in normal SGTC's, but I belive it is folly.

For simply, if this is done, it will force the Primary and secondary to be In Phase. Which Negates the purpose of the Spark Gap (to trap energy in the secondary).

To avoid a strange condundrum, lets then move the secodary far enough from the primary, so there is no magnetic coupling.

At this point, I am guessing that since the primary resonates with radio frequency, then only one wire is needed to connect the two circuits, and ALL voltage increase is due soley to resonance.

Now, this does negate the purpose of the spark gap, so remove it for now, I will come back to this Heart of the Coil.

So far we have a strange circuit, one that is about to get wierder.

In the primary circuit, we now have a redudant component, the primary coil, and the secondary of the NST are both inductors. So, simply Remove the primary coil. For now on, we will use the Secondary of the NST as the primary inductor.

However, a normal conductor must be put in the place of the old primary coil, for the primary capacitor and inductor MUST stay in parrellel, as they were originaly inteanded.

Lastly, the spark gap.

Purpose of the spark gap is to trap energy in the secondary circuit. However, it requires the 90 degree phase shift of a transformer, so, what if we then place the gap in FRONT of the NST?

This new spark gap could then actully be replaced by solid state components, as it only needs to handle 60 HZ, 120 volts. And it would not only trap energy in the secondary, but in the primary as well. (everything AFTER the NST)

This is my idea, a solid state, dual resonant.....not-transformer. That could theoreticly be built to handle even more power than a SGTC, but as effeicient as a SSTC, but simpler than a DRSSTC.

On the bad side....I don't know of a NST in existence that would handle that kind of abuse. So we'd probably have to build a custom transformer....small price to pay for a new type of Tesla Coil!

What do you think?

Proud Mary

Mon Sept 14 2009, 02:45AM

Registered Member #543 Joined: Tue Feb 20 2007, 04:26PM
Location: UK
Posts: 4992

It would help old duffers like me if you stuck some provisional values on it. And what is a 'toroidal' capacitor?

EvilTesla-RG

Mon Sept 14 2009, 03:16AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Provisional Values?

As in values for the components.

I am afraid I do not immediatly know.....To tell the truth, I was coming up with the idea as I was writing it.

It would require some math......so I'd have to brush the dust off of some old equations...

I'm pretty sure the values would would be roughly equal to an equivalent SGTC. Though I don't rightly know, as those rely on a magnetic coupling between the primary and secondary coils, which no longer applies in this case.

I'm sure we can assume the transformer would go from 120 V to around 10 KV..ish.

From there, I havn't a clue. It would depend on what the output frequency is, and the inductance of the step-ups secondary coil.

That may through a kink into the idea. The Secondary coil of an NST (or whatever is used) would probably be high inductance. So to achieve radio frequencies, the primary capacitor would have to be very small.

Picofarad size at first guess??

As for Toroidal Capacitor. I'm afraid I invented some termonalogy, I meant a simple Toroid. Top Load. Shiny sphere or Donut.

Sometimes including a break out point, which confounds me, becouse it strikes me that a breakout point would change the capacitence of the Toroid, changing the Tunning.

Would a picture help?

I know it'd help me...

EDIT:

here is a quick sketch I made in paint shop, I hope it is understandable.

NewTeslaIdea

[Edit: 400 pixels or less]

EvilTesla-RG

Wed Sept 16 2009, 04:09AM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Bump

so no one has any ideas?

Idea is too crazy?

Too vague?

Dr. Slack

Wed Sept 16 2009, 07:53AM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

It would require some math......so I'd have to brush the dust off of some old equations..

Mmm, yes, math. Or simulation. Download one of the circuit simulators suggested in the HVwiki, and model a SGTC and see how it works. Then model what this guy's done. He used some math. I haven't worked through his values, but it looks like he was using an extra LC instead of the pri/sec transformer beloved of conventional TCs to provide some of the same step up. You can do that with LC filters, at a single frequency, but only if you get the values into a reasonable ratio. Mmm, math.

Now put your arrangement into a simulator and play with it for a while. It's a real fast way to experiment with different values. Generally speaking, if something will work in real life, then it will work better in a simulator, when you make make everything ideal by ignoring all those pesky losses and tolerances.

There are several good reasons for including the pri/sec transformer. One is the extra degree of freedom it gives you, second is the safety of the extra level of air-gap isolation from the mains, makes it more likely that you would survive an unintentional streamer hit.

Identifying the spark gap as the thing that traps the energy in the secondary, while it has an element of truth, is rather like identifiying the tires on a car as the thing that enables the brakes to bring it to rest. True, but it misses the bigger picture. The real excitement happens when it fires, quenching is a "nice to have" once the coil is basically working. Putting a spark gap, which is an excellent low impedance very high frequency switch, ahead of your NST is not a good place to put it. Understand why and you will be a lot nearer to your goal. To wring yet more life out of the metaphor, you could improve the braking ability of the tires by dragging an anchor behind the vehicle, but it's not going to do much for the performance.

BTW, this board does not really support bumps. It's been 49 hours since your last post, but you also should have some new information to add. Nobody replying *is* information of a sort, but not the sort the rules have in mind.

EvilTesla-RG

Wed Sept 16 2009, 02:33PM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Hmm...

I see...

I do have a simulator, ProtoLab, but I can never get even the simplist circuits to work.
I'll look as some in the HV wiki

(plug in something like an LC circuit, and nothing happens)

And it doesn't support transformers...

I will have thing about the spark gap thing some more. I havn't a clue where I could learn more, I'v pretty much leached the web of info about Tesla Coils.

Ah, thanks for the info about the Bumb..

Dr. Slack

Wed Sept 16 2009, 07:22PM

Registered Member #72 Joined: Thu Feb 09 2006, 08:29AM
Location: UK St. Albans
Posts: 1659

I do have a simulator, ProtoLab, but I can never get even the simplist circuits to work

Some simulators can be a bit quirky. I can't help you with protolab, but if you download simetrix (not quirk-free by any means, but at least I know where to hit it to get it to work), I can help you with some SGTC circuits that simulate. Once you have an LC "hello world" circuit, it's then easier to play around.

Incidently, if you go back to the circuit you first posted, L1 and L2 together with C2 act as a step-up transformer, at their resonant frequency. Although L1 and L2 are not mutually coupled, they act as if they are an autotransformer when they resonate with C2. The connection to the secondary disturbs this a little, so the whole thing has to be tuned as one. Obviously this needs a bit of engineering to spot the configuration, and then a bit of maths to set the values correctly.

A broad-band auto transformer would require L1+L2 to be a single all-coupled winding, tapped at the junction point between L1 and L2. Conventional TCs use a real transformer, primary to the bottom bit of the secondary to acheive step-up.

vasil

Wed Sept 16 2009, 07:47PM

Registered Member #229 Joined: Tue Feb 21 2006, 07:33PM
Location: Romania
Posts: 506

Your drawing reminds me about Seibt experiments:

http://www.coe.ufrj.br/~acmq/ressona3.jpg

http://www.coe.ufrj.br/~acmq/mk95943.jpg

EvilTesla-RG

Wed Sept 16 2009, 09:32PM

Registered Member #1523 Joined: Sat Jun 07 2008, 02:05PM
Location:
Posts: 97

Interesing.

I'll download Simetrix when I get time.

Very interesting, so you can get the transforming "step-up" effect without magnetic coupling?

jpsmith123

Wed Sept 16 2009, 11:01PM

Registered Member #1321 Joined: Sat Feb 16 2008, 03:22AM
Location:
Posts: 843

Hello EvilTesla-RG,

You might want to try CircuitMaker 2000 which AFAIK is no longer sold or supported, but I've seen it on emule. I find it easy to use and quite helpful for analyzing networks like the one you mention.

I'm interested in the "4th order transformerless multiple resonant network", as it seems to me that this circuit may be analogous to an inductively coupled coaxial resonator (with either straight or helical center conductor), which may be useful as an all metal structure to accelerate electrons.

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