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ZVS flyback driver SSTC

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ZakWolf

Sat Nov 06 2010, 08:06AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
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Posts: 608

I saw an old post where someone used a soda bottle and a ZVS flyback driver to make a SSTC.

Is this possible? If so how?

soda bottle tesla coil

Sulaiman

Sun Nov 07 2010, 11:18AM

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

An sstc secondary needs to be driven with either
- a magnetic field
OR
- a voltage/current injected into the bottom end
at its resonant frequency.

SO you could use a zvs where the resonant inductor is
- a 'normal' sstc primary
OR
- the primary of a transformer with a high voltage secondary connected to the resonator base.

Which is best? ..... I prefer the 'normal' sstc primary approach as it's more 'efficient'
All you need is 2,4,6,.... primary turns centre-tapped.
(plus resonant capacitor, 2 transistors,diodes & resistors and the series/dc inductor)

Arcstarter

Sun Nov 07 2010, 07:15PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

LittleVenture wrote ...

I saw an old post where someone used a soda bottle and a ZVS flyback driver to make a SSTC.

Is this possible? If so how?

soda bottle tesla coil

Not only can you use the driver, but it can be made to work incredibly well. I believe it was Vasil from this forum that made a sstc (actually, it is a dual resonant sstc, but parallel resonance instead of series resonance) with the same circuit and something like 24" sparks and impressively small heatsinks.

ZakWolf

Mon Nov 08 2010, 02:58AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
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Posts: 608

so how many turns do i need for the primary?

Arcstarter

Mon Nov 08 2010, 04:49AM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

LittleVenture wrote ...

so how many turns do i need for the primary?

Think about how the driver itself works... You'll need to make the primary and tank cap resonate at the frequency of your secondary. Use a sgtc tank circuit calculator to find what inductance and capacitance makes what frequency. About 3+3 would be a good place to start.

ZakWolf

Mon Nov 08 2010, 05:30PM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
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I wound a 3+3 primary and hooked that to the driver i turned it on and didnt get anything. Do i need to use some sort of capacitor or am i doing something wrong?

Matt Edwards

Tue Nov 16 2010, 07:16PM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

When I attempted a similar project I used a 30kv 1000pf cap and spark gap before the primary of the coil. I also center tapped each turn on the primary for tuning. It was setup in a similar fashion to a SGTC tank between the flyback and primary. If you do what was suggested by arcstarter and adjust the primary resonance to match the secondary you should be good to go. But I have only seen a small handful of flyback driven coils that produced decent results.

Arcstarter

Tue Nov 16 2010, 08:44PM

Registered Member #1225 Joined: Sat Jan 12 2008, 01:24AM
Location: Beaumont, Texas, USA
Posts: 2253

Oidium45 wrote ...

When I attempted a similar project I used a 30kv 1000pf cap and spark gap before the primary of the coil. I also center tapped each turn on the primary for tuning. It was setup in a similar fashion to a SGTC tank between the flyback and primary. If you do what was suggested by arcstarter and adjust the primary resonance to match the secondary you should be good to go. But I have only seen a small handful of flyback driven coils that produced decent results.

He is not talking about a SGTC, he is talking about a sstc with the ZVS driver directly driving the primary. It works, and produces fantastic results due to the low switching loss nature of the driver, if made well.

What do you mean by "Do i need some sort of capacitor"? Before you use a Tesla coil setup, just try it on a flyback transformer with a tank cap of around .68uf or whatever you want to use.

The capacitor for the sstc will be a much lower capacitance to shift the resonant frequency of the tank circuit way up, to match the secondary's resonant frequency. In that respect, it is a dual resonant sstc, but it is parallel resonance and will give sparks like a typical sstc.

But because of this, there is no secondary feedback, so the primary resonance will have to be adjusted according to secondary loading. The primary resonance may shift a bit when the secondary is loaded due to the coupling, but im not sure how far from resonance it will get.

The tank capacitor will have to be accurate within pf range to insure you get the right freq. Primary inductance can also be tweaked to get the right resonant freq. Look at Richie Burnett's graph of the resonance of a Tesla secondary.

As you can see, just a tiny % away from resonance makes a big difference in the output voltage. The page explaining this graph is here:

Matt Edwards

Wed Nov 17 2010, 12:54AM

Registered Member #2838 Joined: Fri Apr 30 2010, 07:55PM
Location: tehachapi, CA
Posts: 333

My mistake. I should have read the thread more thoroughly. If you get your coil operational you should post some photographs, schematics, etc... As I said before, I tried something similar a while back but couldn't find info online so I ended up going for a spark gap setup which performed poorly.

ZakWolf

Wed Nov 17 2010, 06:57AM

Registered Member #3114 Joined: Sat Aug 14 2010, 08:33AM
Location:
Posts: 608

I am really confused... My ZVS flyback driver works awesome for my flybacks. My ZVS flyback driver has 3 out puts of course i was wondering why i need a capaictor i thought it would be just like a big flyback basically. I just wound 3+3 around the base of the secondary and nothing happened i will try some more and if i get it working i will post info

Could someone make a simple schematic please thanks

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