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my medium sized tesla coil problem help!!!

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mike o.

Thu Aug 13 2009, 08:47PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
Location:
Posts: 13

here is what im running; 10kv 30 ma nst, an mmc made up of 16 1.6kv .22 uf caps, for 13.6 nf's of capacitance, primary is 11 turns of 1/4 inch copper tubing, tapped wherever needed, my secondary is 1100 turns of 26 gauge magnet wire, with no gaps or shorts, my toroid is home made with plastic containers covered in tin foil to look and perform like a professional one, my spark gap is two bolts lined up in a 4 inch pvc pipe, my PROBLEM is when I fire it up with the caps in parallel with my nst, and my spark gap in series with the nst and my primary coil, my spark gap DOES NOT FIRE!... the caps are good, everything is good, I cant figure this stupid thing out!

CT2

Thu Aug 13 2009, 08:53PM

Registered Member #180 Joined: Thu Feb 16 2006, 02:12AM
Location: Ontario, Canada
Posts: 187

When you set up your gap, did you adjust it so it JUST fires with only the NST connected? ie. the gap is spaced properly for 10kv? Btw you will notice a huge preformance increase if you change your single gap to a multiple gap, that is of course once you get it working :P . Other then that I'm not sure what it could be other than a possible wiring problem?

*Edit*

I just looked closer at your pic, what kind of NST is that? It kind of looks like a new style solid state one, which isn't suitable to power your coil as is...

mike o.

Thu Aug 13 2009, 08:55PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
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Posts: 13

my spark gap is set up at 1/4 inch or less right now just until I can get it to fire, any other ideas?

Coronafix

Thu Aug 13 2009, 10:24PM

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

Is that little black thing at the bottom your NST? If so, there is your problem. It's a solid state NST and not suitable for TC use. Also, for when you get a proper tranny, spark gap should be parallel to NST, cap and coil in series with each other.

mike o.

Thu Aug 13 2009, 10:54PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
Location:
Posts: 13

yeah that is my transformer, it is not dc current if thats what your saying, it has 2 5kv ac lines coming out, ive read and talked with people that said it is ok for your caps to be in parallel with your nst and your s.g in series with your primary coil, thanks

CT2

Fri Aug 14 2009, 01:14PM

Registered Member #180 Joined: Thu Feb 16 2006, 02:12AM
Location: Ontario, Canada
Posts: 187

It isn't the fact that it's not DC, infact I'm pretty sure the only way u could get it to work would be to rectify it to DC. It's the HF output (instead of being 60Hz)thats the problem. Wait for some other people on this forum to confirm, but I think you need a new NST, of the older style ie. iron core 60Hz transformer.

mike o.

Fri Aug 14 2009, 01:19PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
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Posts: 13

alright, thanks for the help, I will wait for some more reply's, but this is sounding good so far!

Herr Zapp

Fri Aug 14 2009, 03:11PM

Registered Member #480 Joined: Thu Jul 06 2006, 07:08PM
Location: North America
Posts: 644

mike o -

As Coronafix noted, your high voltage power supply does not appear to be a NST (Neon Sign Transformer); it appears to be a "Solid Stete Gaseous Tube Power Supply". A gaseous tube power supply is NOT a NST.

Take a close look at the nameplate on your power supply and see if it contains the words "gaseous tube", "power supply", "high-frequency", or something similar. If so, it won't work in your Tesla coil. A true 10KV, 30ma iron-core neon sign transformer will weigh at least 6-8 lbs, and won't have a plastic housing.

Just post a good close-up photo of the power supply's nameplate, and forum members will immediately verify what you have.

Two other points:
1. How did you determine the resonant frequency of your primary and secondary circuits; did you use one of the tesla coil design programs? If so, post ALL the design data and the furum will give it a quick sanity check.

2. A Tesla coil will "work" with either the capacitor or the spark gap connected in parallel with the HV transformer's output, but there is greater potential for destroying the NST if the capacitor is connected across the output. When the spark gap is connected across the transformer's output, the transformer's secondary is essentially "shorted" when the spark gap is firing, which help protect the transformer from the high-voltage, high-frequency transients that are present in the primary circuit when the coil is operating. Listen to the collective voice of experience.

Regards,
Herr Zapp

Regards,
Herr Zapp

mike o.

Fri Aug 14 2009, 09:14PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
Location:
Posts: 13

hello, my toroid is made up from one 3 inch diameter metal slinky, wrapped around a chinese take out plastic round container, and a metal pot lid, covered in tin foil, with a bolt that screws into a nut wich is attached to the end of my secondary winding wire, for a good connection, my nst is very light and has a plastic container... heres a pic. I used teslamap to design it but cannot send the file over through this forum, if you have an email address I can though.

mike o.

Fri Aug 14 2009, 09:16PM

Registered Member #2291 Joined: Thu Aug 13 2009, 08:36PM
Location:
Posts: 13

its not letting me post my picture, so heres the info from the transformer case;neon power supply, input 120v , output 10kv 30 ma model QY-11010

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