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LAN_403

Coronafix

Tue Jun 05 2007, 03:44AM

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

Definately cut the excess off the resistors, you are probably getting
flashover occuring. To be safe, make sure all the capacitor ends
are about an inch away from any others.
Coil looks all right, top load a bit small, but you should still get nice sparks off of it.

Yongsoo

Tue Jun 05 2007, 03:21PM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Fixed capacitors and grounded everything using some left over primary coil about 5 inches in the ground. I get like 4 inch streamers off the top of my secondary. It doesn't touch my toroid at all. Also, I get racing sparks near the top of my secondary at 2 fixed spots where the winding isn't all that great. How am I supposed to attatch the top of my coil to the toroid? And does 4 inches off a poorly wound/not tuned sgtc with a 12kv 30ma NST sound reasonable?

Part Scavenger

Tue Jun 05 2007, 04:44PM

Registered Member #79 Joined: Thu Feb 09 2006, 11:35AM
Location: Arkansas
Posts: 673

Just make sure that it makes some sort of contact. Sand the enamel off the wire, and tape or screw it to the toroid. I'd say 4" isn't half bad if your toriod isn't even connected!

Yongsoo

Tue Jun 05 2007, 10:50PM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

I sanded the end of my wire and taped it to my toroid. No results. Black burn marks are appearing where it is sparking on my secondary coil. I'm going to avoid touching it because I really don't want to wind a second coil before my presentation tomorrow. D: Any suggestions? Should I cut off like the top 4 inches of my coil where its sparking. I'd still have about 12 inches and ~800 turns.

GreySoul

Tue Jun 05 2007, 11:05PM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

hrm... can't see it, can't diagnose it... ya know

I'd say it kinda sounds like you're getting a flashover from turn to turn at some point in your coil....

if there's a black spot it's a pretty good chance you've got a short... it's probably not be the end of the world.

If you're really lucky the wire hasn't evaporated yet. The first step would be to coat that area very heavily with some high quality electronic grade shellac, polyurethane, or so forth. If you can get the coating down between each turn where the short is you'll probably be ok again.... ramp up slowly and watch the patch job closely. if it fails skip to the next step...

If the wire is missing from a small area then you'll have to unwind the coil to a bit beyond that point. lightly sand off any black stuff (carbon) from the pipe and then you can either splice in a new section if you feel comfortable doing so or retune the coil for the shorter length. 800 turns is still plenty of wire to get a decent spark.

give the whole coil a few more coats of shellac/lacquer/polyurethane to be safe.

Also, the wire from the coil should go to the top load in a gentle spiral, no sharp turns or crimps in the wire.

...what else...

are there any signs of sparks inside the coil, running down the inside of the pipe?

get back to us.

-Doug

Coronafix

Tue Jun 05 2007, 11:32PM

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

Highly important, no sharp kinks at the top, as this will be a place
where the corona will eject from.
Cutting 4 inches off your coil sounds a bit drastic, that's a third of your coil.

Yongsoo

Wed Jun 06 2007, 12:11AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

I definitely had some sharp turns at the top of my coil. I measured it out and cutting part of my secondary will leave me with 700 turns so I'll probably rewind it tomorrow if coating it doesn't work. Does having sharp turns at the bottom of a coil make a difference?

GreySoul

Wed Jun 06 2007, 01:11AM

Registered Member #546 Joined: Fri Feb 23 2007, 11:43PM
Location: Albuquerque, NM
Posts: 239

having sharp turns anywhere in a high voltage / high frequency device is a big no-no.

Yongsoo

Thu Jun 07 2007, 02:31AM

Registered Member #804 Joined: Fri May 25 2007, 04:42AM
Location:
Posts: 22

Tesla coil is now functional. Huge thanks to everyone here. Couldn't have done it without you guys. I'll be rebuilding it during the summer with a better spark gap, primary coil, secondary coil, a real toroid, and proper tuning. Here's a video I uploaded.

Thanks again. <3

Brett Miller

Thu Jun 07 2007, 02:36AM

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

Yongsoo,

Congratulations! Looking good so far!!!

-Brett

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