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Need idea for SGTC

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LAN_403

Hazmatt_(The Underdog)

Sat May 22 2010, 03:54AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

your cap is going to eat itself up if it's not under oil.
If stressed hard enough, glass plate caps can detonate, so be aware of that fact.
Also if your cap is not the right capacitence, you will probably overstress your NST, destroying one of the windings.

I hope it doesn't fail on you, but be cautious and ramp up the NST with a variac to be safe.

quicksilver

Sat May 22 2010, 03:57PM

Registered Member #1408 Joined: Fri Mar 21 2008, 03:49PM
Location: Oracle, AZ
Posts: 679

Sulaiman wrote ...

The basic circuit diagram is as here

Notice anything missing?

It appears that in the diagram there exists one spark gap (we don't know if that's the safety gap or what). But beyond the cap we go directly into the primary. Should not a spark gap be after the cap? This is the only time I have seen a diagram of an SGTC wherein the SG is before the cap and is not utilized as a safety gap. - So really the diagram is a setup for cap failure; no? More importantly the grounding is via the secondary alone.

tulkas

Sat May 22 2010, 05:19PM

Registered Member #2865 Joined: Tue May 18 2010, 10:59AM
Location: persia
Posts: 37

reply to Hazmatt_(The Underdog):
what do you mean of stressed ?
my cap is 15-17 nF (calcuted by capacitance meter.)
and i didn't have any problems with it but some silenced JIIIZ sound when the SSG was wide .
reply to suleiman :
i'm using a 2400 RPM motor with 10 rotary electrodes an 2 statics.
the wires on NST are what i think safety gap (i don't know anything and nobody explains or gives schematics about safety gap.)

803

Sat May 22 2010, 05:30PM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

You mean 2 years of learning is too much?!ill:-((

tulkas

Sun May 23 2010, 12:10PM

Registered Member #2865 Joined: Tue May 18 2010, 10:59AM
Location: persia
Posts: 37

to 803 :
what ?

803

Sun May 23 2010, 12:55PM

Registered Member #2807 Joined: Fri Apr 16 2010, 08:10PM
Location:
Posts: 191

I spent 2 years doing theory and thinking about tesla coils before I built one

tulkas

Sun May 23 2010, 01:36PM

Registered Member #2865 Joined: Tue May 18 2010, 10:59AM
Location: persia
Posts: 37

nice assiduity but why did you tell it here .?
TO ALL :
i'm thinking about magnifier and i have an idea ( i saw the real schematic) can we attach ultra coil ? what is connected to extra coil as extra connected to secondary ?

foolish ideas
tulkas

Hazmatt_(The Underdog)

Sun May 23 2010, 07:50PM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

Overstressing the transformer meaning:

If the capacitor is the resonant value matched to the reactance of the transformer, a resonance will cause the terminal voltage to rise beyond what the transformer is ment to handle and fry itself due to dielectric breakdown.

NST's are designed to be connected to a luminous tube, which is a diode of sorts, clamping a 10KV transformer down to ~7KV. You can call up Franceformer yourself and find out that their insulation is ment to be run continuous at the tube voltage, not open, and that most of the time its tar potted, or resin now, and it's not intended to be run at open circuit voltages, a real bummer for most of us.

If the cap value is too high, then you draw excessive current from your ~34 AWG HV winding and eventually it burns out the coil that way.

And to a limited extent, snubber filters help reduce the high voltage kickbacks that come back to the transformer as the Tesla system rings down. It becomes more important as the energy stored gets bigger. In small systems the core reactance can be enough to prevent damage to the coils.

You'll learn more as you go along.

tulkas

Mon May 24 2010, 06:00AM

Registered Member #2865 Joined: Tue May 18 2010, 10:59AM
Location: persia
Posts: 37

TNX .
you mean if it not happens yet it will not happen in future ?
(sorry for asking this here : does anybody knows what happens to original Tesla coil which used in Colorado springs ?)

Hazmatt_(The Underdog)

Tue May 25 2010, 04:53AM

Registered Member #135 Joined: Sat Feb 11 2006, 12:06AM
Location: Anywhere is fine
Posts: 1735

You could build up enough stress over time to cause a failure, yes. Corona is one and that buzzing sound you hear or a blue discharge on the capacitor plates is corona which could cause a failure in the future. That's why I recommended putting your cap under oil to help suppress the corona.

I think the original lab caught fire, not sure.

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