Rail strikes and some internal "popping"
IamSmooth, Tue May 29 2007, 04:04AMI just tried my Tesla coil for the second time and I put the video on YouTube
I would like to hear what you experienced coilers think? Is it ok? I got 5 foot strikes with power input from two 15kv/60ma NSTs. The toroid is 24" x 12" x 6". Cp is 0.05uf. I have a synch rotary gap/controller and a filter. The secondary is 6" x 29.5" wound on acrylic.
Are the strikes on the guard rail reasonable? Do I need a taller secondary?
Also, when I get the power close to maximum I sometimes hear a popping sound that seems to be coming from the inside of the toroid and the streamers shrink in size or disappear until I lower the power and raise it back up again. Any suggestions?
Re: Rail strikes and some internal "popping"
Electroholic, Tue May 29 2007, 04:37AM
caps popping and arking inside?
Electroholic, Tue May 29 2007, 04:37AM
caps popping and arking inside?
Re: Rail strikes and some internal "popping"
Brett Miller, Tue May 29 2007, 05:36AM
iamsmooth,
I thought your coil footage was great! Love the sync rotary action. The sparks look great too, I see nothing at all unreasonable about an occational strike rail hit, and I have seen the same on other coils with strike rails. Personally, my largest disruptive coil featured a static gap and a single 12/60 NST, and my largest sparks were 45 inches. However, I used no strike rail. I prefer to use a two toroid system where there is a smaller ACR (Anti Corona Ring) below the main toroid. I position these in such a way that they provide efield shaping that ensures streamers are directed horizontally and clear of the primary. I've never had a primary strike using this method, but then I did not run your power levels either, so I can't say for certain that this technique would help in your system. In any case, congratulations, your coil looks like a great success!
-Brett
Brett Miller, Tue May 29 2007, 05:36AM
iamsmooth,
I thought your coil footage was great! Love the sync rotary action. The sparks look great too, I see nothing at all unreasonable about an occational strike rail hit, and I have seen the same on other coils with strike rails. Personally, my largest disruptive coil featured a static gap and a single 12/60 NST, and my largest sparks were 45 inches. However, I used no strike rail. I prefer to use a two toroid system where there is a smaller ACR (Anti Corona Ring) below the main toroid. I position these in such a way that they provide efield shaping that ensures streamers are directed horizontally and clear of the primary. I've never had a primary strike using this method, but then I did not run your power levels either, so I can't say for certain that this technique would help in your system. In any case, congratulations, your coil looks like a great success!
-Brett
Re: Rail strikes and some internal "popping"
Steve Ward, Tue May 29 2007, 05:54AM
Sounds very characteristic of internal arcing inside your secondary. Ive had it happen too, and the sound of "sparks inside the toroid" and loss of output were exactly what i noted. Are there any sharp points near the ends of the secondary that might promote internal discharges? Fix them if they exist. Otherwise, you might need internal baffles.
Coil looks great, BTW.
Steve Ward, Tue May 29 2007, 05:54AM
Sounds very characteristic of internal arcing inside your secondary. Ive had it happen too, and the sound of "sparks inside the toroid" and loss of output were exactly what i noted. Are there any sharp points near the ends of the secondary that might promote internal discharges? Fix them if they exist. Otherwise, you might need internal baffles.
Coil looks great, BTW.
Re: Rail strikes and some internal "popping"
Coronafix, Tue May 29 2007, 06:53AM
Very nice!!
Maybe try a breakout point.
Coronafix, Tue May 29 2007, 06:53AM
Very nice!!
Maybe try a breakout point.
Re: Rail strikes and some internal "popping"
hvguy, Tue May 29 2007, 08:11AM
Nice coil and good output for 15/120.
To second Steve, the problem sounds just like internal arcing. If the secondary is flashing over inside you may have caught it just in time. One good arc can carbon track your form and destroy the secondary. If you check the coil and find it's not flashing over I would start checking connections and looking for arcing elsewhere.
hvguy, Tue May 29 2007, 08:11AM
Nice coil and good output for 15/120.
To second Steve, the problem sounds just like internal arcing. If the secondary is flashing over inside you may have caught it just in time. One good arc can carbon track your form and destroy the secondary. If you check the coil and find it's not flashing over I would start checking connections and looking for arcing elsewhere.
Re: Rail strikes and some internal "popping"
sparky, Wed May 30 2007, 04:02AM
That is a GREAT video! I really enjoyed it... thanks for sharing! 5 -6 ft is about normal for a Tesla Coil that size with that power level. Good work! Beautifully built coil I must say!!!
I have always made my secondary forms tall --- lots and lots of extra turns to prevent secondary to primary flash over. Right now I'm in the middle of building an 8" X 46" Tesla secondary wound with 24AWG. --- we will see what the extra inductance will do to the output of the streamers.
sparky, Wed May 30 2007, 04:02AM
That is a GREAT video! I really enjoyed it... thanks for sharing! 5 -6 ft is about normal for a Tesla Coil that size with that power level. Good work! Beautifully built coil I must say!!!
I have always made my secondary forms tall --- lots and lots of extra turns to prevent secondary to primary flash over. Right now I'm in the middle of building an 8" X 46" Tesla secondary wound with 24AWG. --- we will see what the extra inductance will do to the output of the streamers.
Re: Rail strikes and some internal "popping"
Shaun, Thu May 31 2007, 07:35PM
I totally agree, awesome video. If you are concerned about rail strikes, I would say definetely go with the double toroid setup. The smaller toroid doesn't even need to be well constructed, from my experience. Just for a tiny bit of e-field shaping/shielding.
Shaun, Thu May 31 2007, 07:35PM
I totally agree, awesome video. If you are concerned about rail strikes, I would say definetely go with the double toroid setup. The smaller toroid doesn't even need to be well constructed, from my experience. Just for a tiny bit of e-field shaping/shielding.
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