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Coronafix

Tue May 22 2007, 10:02AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Hi all,

I have been looking at what info there is available on building a Tesla magnifier,
mainly

and

Most people talk about magnifiers but it seems few build them.
I saw a reference to a 2:3:4 magnifier that Terrry Fritz is supposed
to have built but couldn't find the info anywhere.
I have learnt a lot by pumping a lot of power into a small coil
and now I want to use that small coil as a tertiary.
I know coupling can be an issue with magnifiers but I thought of using mica sheet
between the primary and secondary. This should solve the problem if designed well.
Secondary of course will be about 1/4 the inductance of the tertiary.
Has anyone got any successes/failures with making magnifiers?
Regards,
Michael

Brett Miller

Tue May 22 2007, 03:12PM

Registered Member #593 Joined: Tue Mar 20 2007, 12:32AM
Location:
Posts: 50

Michael,

There has been a plethora of magnifier work since I have been coiling (mid 90's to present). Richard Hull all the way up to Steve Ward and Dan Mccauley with a ton of people in between. Steve had quite a bit of success with a DRSSTC magnifier and has quite a table of efficiency data on his site. John Freau also did quite a bit of disruptive coil magnifier research as well, trying fast break rates with an ASRG in order to determine if efficiency could be greater than a 2 coil system. You may be getting the impression that people talk about maggies and don't build them simply because most folks have already done their magnifier experiments, or have realized that it's a lot of work, for the same length sparks.

Every time I think about magnifiers I remember that no one has been able to truly show any real benefit (spark lengh vs input power) to using a 3 coil system, other than the fact that the tertiary resonator gets most of the sparks away from the primary and secondary. In all the cases I've examined, output from a magnifier (for a given input VA) never exceeds that of a well designed 2 coil system.

You ought to check this out:

http://www.stevehv.4hv.org/DRSSTCmag1.htm

http://www.stevehv.4hv.org/DRSSTCmag2.htm

and here's some numbers to think about:

http://www.stevehv.4hv.org/2vs3coil.htm

Here's an excerpt from John Freau:

3) Magnifiers

Ques: I heard that magnifiers are much more efficient than normal TC's because they use tight coupling and that they also require smaller capacitors, higher breakrates and special rotary gaps?

Ans: Magnifiers work very similarly to normal TC's. Although the driver coupling is tight, the overall coupling is similar to a normal TC. In my work, magnifiers worked best using the same cap sizes and breakrates as a normal TC. I did not see any advantage in using a special type of rotary gap. I have never seen a magifier that outperformed a normal well built TC.

(end quote)

...

Nevertheless, a lot of people still build them, and have a lot of fun. I know a guy on this forum who is tooling up for a huge magnifier right now, and I'm sure he'll announce it soon. I asked him if he thought he could achieve better performance than a two coil system. He said he didn't think so, but he wanted to build it anyway just for the fun and experiece. Folks have even built VTTC and SSTC magnifiers as well. There's a thread one here where a guy base fed a third resonator on his SSTC just to lower the Fo. So yes, the maggie is alive and well!

Good luck.

-Brett

Sulaiman

Tue May 22 2007, 04:28PM

Registered Member #162 Joined: Mon Feb 13 2006, 10:25AM
Location: United Kingdom
Posts: 3140

As far as I know (not much really) arc-length depends mainly on POWER
(John Freau's famous 1.7SQRT(power) etc.

I think Tesla changed to 'magnifier' topology because he wanted maximum voltage at the topload WITHOUT breakout/arcs/sparks.
So the main reason for a magnifier topology seems to be for the wireless transmission of power.

sparky

Wed May 23 2007, 03:38AM

Registered Member #530 Joined: Sat Feb 17 2007, 07:56AM
Location: Victoria BC, Canada
Posts: 178

Finer gauge wire on a large secondary form + a large thick primary can actually replicate the same output as a magnifier.

---its all in the inductance.

Coronafix

Wed May 23 2007, 04:05AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Thanks guys,
After mentioning john Freau's maggie I found an interesting pupman
post that discusses his results. Thanks.
Steve's stuff is also interesting, nice sparks off the tertiary there.
I am currently getting 18" sparks off my 2" X 9" coil, so I want to
use this coil ('lil pepper) as the tertiary. This will involve only winding
another small secondary on a 3.5" former and a new primary.
Still keen to give the maggie a go though, even knowing longer sparks
probably won't be forthcoming.

Steve Ward

Wed May 23 2007, 05:16AM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

I remember hearing about Terry's small magnifier too. I think its performance just sucked (even after one of the mathematics guys on the TCML worked out the "perfect" combination of parameters) and the project just dropped out of sight.

My experience with magnifiers: what a pain in the ass. Keeping the primary and secondary from arcing to eachother is pretty much impossible in some cases.

Coronafix

Wed May 23 2007, 06:23AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

Steve Ward wrote ...

I remember hearing about Terry's small magnifier too. I think its performance just sucked (even after one of the mathematics guys on the TCML worked out the "perfect" combination of parameters) and the project just dropped out of sight.

My experience with magnifiers: what a pain in the ass. Keeping the primary and secondary from arcing to eachother is pretty much impossible in some cases.

Yeh, that was Antonio Carlos M. de Queiroz of which the first link I had was. That is what I was also wondering, if the
maths that he worked out actually worked. The one that he built didn't seem to perform very well but he mentioned that Terry had built one. He says it has to work with three frequencies of whole number ratios, 1:2:3; 1:2:5; 2:3:4; 2:3:6; etc.
Concerning the arcing over, I believe mica sheeting that you get at neon suppliers could work well to insulate the
primary and secondary and get a good coupling. You have to heat it with a oxy to bend it, but will withstand a lot of voltage.

Steve Ward

Wed May 23 2007, 05:49PM

Registered Member #146 Joined: Sun Feb 12 2006, 04:21AM
Location: Austin Tx
Posts: 1055

He says it has to work with three frequencies of whole number ratios, 1:2:3; 1:2:5; 2:3:4; 2:3:6; etc.

Yeah, thats so that eventually all 3 frequencies beat and sum up to a maximum at some point in time. If they arent whole number ratios, then you wont get the biggest peak. From an analytical point of view, it makes sense (Antonio is pretty sharp), but realistically i dont think it matters all that much.

The mica sheet sounds interesting. I didnt know you could fuse it with heat. That will be critical to getting any use out of it. When i tried to insulate my secondary on the large magnifier i had layers of PP sheeting (1/16 inch thick) arranged so that the creepage distance around them was very large. The sparks still eventually crept about 3-4 feet across the PP surface to hit my primary

Coronafix

Thu May 24 2007, 04:57AM

Registered Member #160 Joined: Mon Feb 13 2006, 02:07AM
Location: Melbourne, Australia
Posts: 938

It seems that there are a lot of complex harmonics that occur in the
topload. I think it would be extremelly difficult to build a maggie to the
exact mathematics he uses, especially when you find that you have to
add a corona ring or two, then all the calcs are out the window.
Regarding the mica sheet, I don't think it can be fused, but because
it is very hard, you need to heat it to curve it into a shape.
The creeping does sound like a big problem though.
I know a mil of mica will withstand a hell of a lot more voltage than
a mil of PP, but creeping will still occur if it's not sealed or doubled over enough.

Sparrow338

Fri May 25 2007, 01:36AM

Registered Member #661 Joined: Sat Apr 21 2007, 03:17AM
Location: Ventura, CA
Posts: 41

Could you maybe run the entire primary and secondary side under oil? Be a lot of work though sealing it all but it would work great.

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