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No Toroid Discharges

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LAN_403

Nyx

Sun Mar 18 2007, 09:05PM

Registered Member #586 Joined: Sat Mar 17 2007, 06:51AM
Location:
Posts: 13

Hello Ive setup a SGTC and got it to start. The spark gap fires but I dont get any discharges from the toroid. I noticed that a fan 1m away started rotating when I switch on the power to the TC.

Im using a 9kV 30mA TC, 15x2strings 0.67uF 1kV polypropene caps, about 11 turns of 9mm diameter primary coil in a conical shape ('inverse-saucer') with an angle of about 45 degrees. My secondary is 900turns, 4in by 20in of 24AWG enamel wires. My dischare terminal is spherical with 10cm diameter and looks kinda small sitting on top of the secondary. I connected the secondary ground to a water pipe 10m away from the coils.

Will a poorly tuned/untuned TC give any streamers?

...

Sun Mar 18 2007, 10:13PM

Registered Member #56 Joined: Thu Feb 09 2006, 05:02AM
Location: Southern Califorina, USA
Posts: 2445

Can you draw sparks off the output sphere with a grounded wire?

It is possible that it is too smooth, and you are not producing enough voltage for breakout. Try adding a piece of solid copper wire (or whatever) sticking out 8" from the sphere.

Also, a mistuned coil can definitely do what yours is.

Did you use any software to calculate the values of the tank cap/primary turns?

Nyx

Sun Mar 18 2007, 10:58PM

Registered Member #586 Joined: Sat Mar 17 2007, 06:51AM
Location:
Posts: 13

... Thanks for your reply.

When you mentioned grounded wire, do you mean a wire connected to the AC mains ground, or to the same ground as the secondary coil?

I'll try sticking the wire to the topload.

I used DeepFriendNeon.com's javascript calculations but my primary coil is conical instead of flat spiral which is what the javascript calculated for me.

I probably fried my transformer. Resistance across the output terminals is infinite and the spark gap doesnt fire when the primary coil is connected but does fire without the primary coil connected. Are these signs of a dead transformer?

Myke

Mon Mar 19 2007, 12:03AM

Registered Member #540 Joined: Mon Feb 19 2007, 07:49PM
Location: MIT
Posts: 969

Remove the Xfmr and see if you can draw an arc from it. If you can't then your Xfmr night be dead (check your breaker or your GFI if you have one).

Don't conect the ground to the mains ground otherwise you will get a lot of RF put into the ground and it may kill some sensitive equipment. The ground should be conecteed to the other end of the secondary. If it is a big coil outside then conect it to the ground (earth) too.

Nyx

Tue Mar 20 2007, 01:34AM

Registered Member #586 Joined: Sat Mar 17 2007, 06:51AM
Location:
Posts: 13

My xfmr seems to be working again lol. Used a crocodile clip connected to the secondary ground and got a 5in spark between the clip and the wire you asked me to place on the output sphere.

Is my sphere too smooth being the reason i dont get sparks coming out from all over the output sphere like those i see in photos?

Nyx

Tue Mar 20 2007, 03:31AM

Registered Member #586 Joined: Sat Mar 17 2007, 06:51AM
Location:
Posts: 13

Here's how mine looks like

1174361483 586 FT22194 Tesla Streamer 01

Coronafix

Tue Mar 20 2007, 08:46AM

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

I'd say that you have about seven times the amount of capacitance that you need.
You have 89.3nf when you need about 12nf to be LTR.
Your transformer is not able to charge that large a capacitance.
It would have been resonantly charging if your caps were 0.067uf instead of 0.67uf.
Your top load should be bigger too, you'll get arcing to your secondary.

Nyx

Tue Mar 20 2007, 11:03AM

Registered Member #586 Joined: Sat Mar 17 2007, 06:51AM
Location:
Posts: 13

Sorry i meant to say my caps are 0.067uF. I'll try a larger topload. How do you get the top load to have sparks coming out in all directions?

uzzors2k

Tue Mar 20 2007, 05:38PM

Registered Member #95 Joined: Thu Feb 09 2006, 04:57PM
Location: Norway
Posts: 1308

Is that an ikea topload? I have two of those 12 cm bowls which are going in my TC too. You should be able to achieve 10-15 inch sparks if you tune your TC properly, and if you can achieve that sparks shooting out in all directions will occur too. Your topload should be pretty smooth to send sparks out everywhere though.

What is your secondary's resonant frequency? I would try making the flat spiral coil that you calculated first, the inductance of your current primary could be off by quite a bit, which will throw your TC out of resonance.

gentoo_daemon

Tue Mar 20 2007, 06:36PM

Registered Member #512 Joined: Sat Feb 10 2007, 05:42PM
Location: Chico, CA
Posts: 25

Isn't 67nF still very large?

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