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Twin Spark Gap coils out of phase

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LAN_403

vasil

Thu Dec 25 2008, 02:19AM

Registered Member #229 Joined: Tue Feb 21 2006, 07:33PM
Location: Romania
Posts: 506

Nice sparks Steve C!

StevenCaton

Sat Jan 03 2009, 01:57AM

Registered Member #1845 Joined: Fri Dec 05 2008, 05:38AM
Location: California
Posts: 211

To be honest, I'm not really impressed with the output of this system, which is 45 inches between coils. I was hoping for something much closer to 72 inches.

I think I am going to add some capacitance by making smaller toroids to place on top of the big ones. I will then retune the system with the added capacitance.

I'll let you guys know if this works.

rp181

Sat Jan 03 2009, 02:40AM

Registered Member #1062 Joined: Tue Oct 16 2007, 02:01AM
Location:
Posts: 1529

Is there a picture here of it running that im not seeing? :)

StevenCaton

Sat Jan 03 2009, 03:15AM

Registered Member #1845 Joined: Fri Dec 05 2008, 05:38AM
Location: California
Posts: 211

Is there a picture here of it running that im not seeing? :)

Yes, I posted a link to a video, look several posts upwards

StevenCaton

Mon Jan 05 2009, 04:37AM

Registered Member #1845 Joined: Fri Dec 05 2008, 05:38AM
Location: California
Posts: 211

My idea of adding more capcitance to each coil worked!

Before, I would get 45 inch sparks between coils very seldom. Maybe a continuous spark would form every 10 seconds.

Now the coils are spaced apart 49 inches, and I get sparks the form between the two and connect almost every second. The new toroids I put on the coils are the same size as the existing ones. So each coil has a double toroid. Adding these toroids dropped the resonant frequency somewhat so I had to adjust the tap point and add another turn on each primary coil.

Well, I improved it, but I'm still not anywhere near where I want to be with this system, in regards to spark length. I'm not sure what else I can do to make this thing perform any better. Nevertheless, its still pretty impressive to see in person. I'll take another video of the system since its been improved and post it when I find the time to do that this week.

Andyman

Wed Jan 07 2009, 12:19AM

Registered Member #1083 Joined: Mon Oct 29 2007, 06:16PM
Location: Upland, California
Posts: 256

Is that strike rail one continuous loop, or is there a break in it that's obscured by the coil? If it is a continuous loop, that would explain the short spark length.

StevenCaton

Wed Jan 07 2009, 07:23PM

Registered Member #1845 Joined: Fri Dec 05 2008, 05:38AM
Location: California
Posts: 211

Its an open loop. Thats not the problem
The sparks don't go near the strike rail anyway so I'm going to get rid of it.

Would getting rid of the strike rails make the sparks longer?

I found that with my SSTC, bringing a metal object in prescence of the toroid would decrease the spark length. Maybe getting rid of those useless strike rails will help me gain some length.

Arcstarter

Wed Jan 07 2009, 09:14PM

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

I would suggest keeping the spark rail. If for some reason the secondary voltage got too high and didn't connect the spark to the other coil, you would want that extra protection to ensure all primary components stay safe. After all, those are some nice caps and transformers, why risk it?

The strike rail would not reduce spark length. At least not much. As long as it is opened and inch or so, it should not reduce energy coupled to secondary.

When you bring something close to the toroid, it increases capacitance, which reduces resonant frequency, which makes it so that the tuning is off.(Didn't explain that very well.)

Maybe you should try tuning some more. Get some smoother toroids and that will prevent corona losses from sharp points, so the coil can concentrate all energy into that one spark, instead of pointless breakout, that you can even see sometimes. I know it sounds like i am making the tesla coil sound like a person or something, but you get what i meant, right?

Even if you have the tuning right with the current topload, maybe the topload just isn't right for your coil? Kinda like having a really tall skinny secondary, even if you have it tuned correctly, it may not put out the greatest spark length due to the dimensions.

StevenCaton

Sun Feb 01 2009, 03:23AM

Registered Member #1845 Joined: Fri Dec 05 2008, 05:38AM
Location: California
Posts: 211

Is excessive corona breakout on top of a secondary coil generally a sign that the secondary needs to be bigger. (slightly larger diamter, height, wire size, etc.) Or is this just something that one will always have to deal with when constructing tesla coils.
When I say "excessive breakout" I mean that there are continuous 1.5 or 2 inch corona breakouts from the top of the secondary coil during operation.

I have been thinking I may wind two new secondaries that have larger parameters to improve the output of this system.

Mads Barnkob

Sun Feb 01 2009, 09:59AM

Registered Member #1403 Joined: Tue Mar 18 2008, 06:05PM
Location: Denmark, Odense C
Posts: 1968

SteveC wrote ...

Is excessive corona breakout on top of a secondary coil generally a sign that the secondary needs to be bigger. (slightly larger diamter, height, wire size, etc.) Or is this just something that one will always have to deal with when constructing tesla coils.
When I say "excessive breakout" I mean that there are continuous 1.5 or 2 inch corona breakouts from the top of the secondary coil during operation.

I have been thinking I may wind two new secondaries that have larger parameters to improve the output of this system.

Your toploads are rather high above the secondary top, if I recall correct the underside of the topload should tangent the top winding of the secondary, it could also just be a matter of isolation, maybe you need to apply a thicker layer of varnish in order to kill the corona.

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