Tesla Coil Design issues.
Ken M., Sat Mar 31 2007, 06:58PMI'd like to start by saying Hello to everyone in this forum group. This is kinda my first and ongoing attempt to get an actual operating tesla coil up and running.
I have a:
Primary: Helical 12AWG speaker wire with 16 turns wrapped around a 2" diameter PVC pipe with ~1/2" space between it and the secondary.
Secondary:
Height: 6" (From bottom winding to top winding)
Diameter: 1.25"
Wire AWG: 36 enamled copper wire
Coil form: Plastic florescent light case thingy
# of turns: ~1015
top load: Spun aluminum toriod 1" ring diameter and 6" overall diameter
Heres a picture of it:
Anyways my issue is that I have tryed various designs and setups with coil, everything from Jan's DRSSTC design to standard SGTC design and a design that used a HVDC power supply (From a flyback) to power this and I cna never seem to get it to work, With the exception of the HVDC power supply design which produced a 1/4" ultra thin arcing from top bolt with no topload on it. At least until the MMC tankcaps became a light show.
So I'm just wondering if could get some info maybe if it should have a bigger secondary? What kinda of driver circuit, i.e SS. DRSS, or the good ole fashioned SG. Any suggestions are greatly appreciated.
Re: Tesla Coil Design issues.
HV Enthusiast, Sat Mar 31 2007, 07:20PM
well, i guess the first question to ask what is your calculated (or measured) fres of the secondary. I'm guessing the resonant frequency is pretty high on that thing based on my gut feel.
HV Enthusiast, Sat Mar 31 2007, 07:20PM
well, i guess the first question to ask what is your calculated (or measured) fres of the secondary. I'm guessing the resonant frequency is pretty high on that thing based on my gut feel.
Re: Tesla Coil Design issues.
Ken M., Sat Mar 31 2007, 07:25PM
From what Teslamap 5 says its about 811.02K, but from what I gave that simulator\calcualation program only figures For a SGTC, but i'd kinda prefer to go wit heitehr SSTC or a DRSSTC if at all possible. To go along with that it'd be nice to be able to have it running with only perhaps 60v max AC or DC to drive the coil, considering I'm just after a coil that will produce visible arcs, say maybe 3-6 inchs max would be nice long would be cool but, for now I'll set my goals small.
Ken M., Sat Mar 31 2007, 07:25PM
From what Teslamap 5 says its about 811.02K, but from what I gave that simulator\calcualation program only figures For a SGTC, but i'd kinda prefer to go wit heitehr SSTC or a DRSSTC if at all possible. To go along with that it'd be nice to be able to have it running with only perhaps 60v max AC or DC to drive the coil, considering I'm just after a coil that will produce visible arcs, say maybe 3-6 inchs max would be nice long would be cool but, for now I'll set my goals small.
Re: Tesla Coil Design issues.
Marko, Sat Mar 31 2007, 07:35PM
Yep, Fres is going to be really high, about a MHz. I would either go with a small SSTC sucha s this one
or a small flyback powered SGTC. For a SGTC, you need way lower coupling; definitely a primary redisign, to flat or archimedas spiral and with something you can tap... 3mm full copper wire would be OK.
What caps are you using for your MMC?
Marko, Sat Mar 31 2007, 07:35PM
Yep, Fres is going to be really high, about a MHz. I would either go with a small SSTC sucha s this one
or a small flyback powered SGTC. For a SGTC, you need way lower coupling; definitely a primary redisign, to flat or archimedas spiral and with something you can tap... 3mm full copper wire would be OK.
What caps are you using for your MMC?
Re: Tesla Coil Design issues.
Ken M., Sat Mar 31 2007, 08:01PM
Before the light show I think....they were a 3x3 of 2.2nF 7500v as for right now nothing, just because I was kinda looking for a suggestion towards what type of TC go with and it looks like it'll be a SSTC.
Ken M., Sat Mar 31 2007, 08:01PM
Before the light show I think....they were a 3x3 of 2.2nF 7500v as for right now nothing, just because I was kinda looking for a suggestion towards what type of TC go with and it looks like it'll be a SSTC.
Re: Tesla Coil Design issues.
Marko, Sat Mar 31 2007, 08:18PM
Capacitor type is very important. They must be polypropylene, at leas foil or foil+ metallization.
I also think small SSTC with Steve's circuit would definitely be a good start for it...
Marko, Sat Mar 31 2007, 08:18PM
Capacitor type is very important. They must be polypropylene, at leas foil or foil+ metallization.
I also think small SSTC with Steve's circuit would definitely be a good start for it...
Re: Tesla Coil Design issues.
Ken M., Sat Mar 31 2007, 09:08PM
Yea I tried that design "Slightly" But a few different parts and it was a bad.
A new question popped into my mind while searching for the parts since I didn't have most of the major parts for that design, With the amount of RF and noise produced by a coil what would be an operation MAx distance for the antenna to be away from the coil, and still get the stacato effect?
Ken M., Sat Mar 31 2007, 09:08PM
Yea I tried that design "Slightly" But a few different parts and it was a bad.
A new question popped into my mind while searching for the parts since I didn't have most of the major parts for that design, With the amount of RF and noise produced by a coil what would be an operation MAx distance for the antenna to be away from the coil, and still get the stacato effect?
Re: Tesla Coil Design issues.
Bennem, Sat Mar 31 2007, 10:33PM
800khz secondary is too high for a DRSSTC,
Derek Woodroff has a small coil working at around 500khz,
my smallest DRSSTC runs at 400khz and
that was rather challenging!
Bennem, Sat Mar 31 2007, 10:33PM
800khz secondary is too high for a DRSSTC,
Derek Woodroff has a small coil working at around 500khz,
my smallest DRSSTC runs at 400khz and
that was rather challenging!
Re: Tesla Coil Design issues.
Ken M., Sun Apr 01 2007, 03:22AM
well...I was kinda thinking\ try to find a way to test some parts of mine out, and so I decided to try another of Steve's (Ward) DRSSTC designs out namely with all the same stuff with the exception of his power supply, only because I have some PC supplys sitting around and they have a fair amount of current available. When I first tryed it I didn't think the 555 timer wouldn't matter untill I burnt out a hrz445 and had my PSU shut down several times, so I added the timer with a reduction of the the 10k resistor just before c5 and swapped the fet with the last high current 100v fet I had... To my amusement i was able to draw an arc only about 1\16th an inch I believe heres a few pics mostly just for my own proof that i'm making HV and just getting lucky.
If ur wondering, I'm running it off the 12v out of the PC PSU for this aside from upping the voltage and other suggestions, would be terrific!
Ken M., Sun Apr 01 2007, 03:22AM
well...I was kinda thinking\ try to find a way to test some parts of mine out, and so I decided to try another of Steve's (Ward) DRSSTC designs out namely
with all the same stuff with the exception of his power supply, only because I have some PC supplys sitting around and they have a fair amount of current available. When I first tryed it I didn't think the 555 timer wouldn't matter untill I burnt out a hrz445 and had my PSU shut down several times, so I added the timer with a reduction of the the 10k resistor just before c5 and swapped the fet with the last high current 100v fet I had... To my amusement i was able to draw an arc only about 1\16th an inch I believe heres a few pics mostly just for my own proof that i'm making HV and just getting lucky.
If ur wondering, I'm running it off the 12v out of the PC PSU for this aside from upping the voltage and other suggestions, would be terrific!
Re: Tesla Coil Design issues.
Ken M., Tue Apr 03 2007, 09:50PM
Ok, well after having Fet failure at 12v (Fet was rated for 55v at 20A) and getting unacceptable arc lengths I decided to revise my secondary,
Old secondary: 1.25in Dia
5-5.5in tall
~1000 turns of 36AWG Magnet wire
Fres: ~800KHz
New Secondary: 2in Dia
~8in tall
~1500turns
New Fres: ~400KHz
I did this to seeif it would increase the output and allow the fet/fets to run a little bit smoother instead of pumping high Frequencies and current into it. Anyone have any ideas how much this will improve my output with a 12v in, or even upto ~30v in? P.S. Winding a secondary by hand with 36AWG wire sucks!
Ken M., Tue Apr 03 2007, 09:50PM
Ok, well after having Fet failure at 12v (Fet was rated for 55v at 20A) and getting unacceptable arc lengths I decided to revise my secondary,
Old secondary: 1.25in Dia
5-5.5in tall
~1000 turns of 36AWG Magnet wire
Fres: ~800KHz
New Secondary: 2in Dia
~8in tall
~1500turns
New Fres: ~400KHz
I did this to seeif it would increase the output and allow the fet/fets to run a little bit smoother instead of pumping high Frequencies and current into it. Anyone have any ideas how much this will improve my output with a 12v in, or even upto ~30v in? P.S. Winding a secondary by hand with 36AWG wire sucks!
Re: Tesla Coil Design issues.
Dr. Dark Current, Wed Apr 04 2007, 05:55PM
just a quick question, isn't your coil form slightly conductive, which could result in big performance drop?
Dr. Dark Current, Wed Apr 04 2007, 05:55PM
just a quick question, isn't your coil form slightly conductive, which could result in big performance drop?
Re: Tesla Coil Design issues.
Steve Ward, Wed Apr 04 2007, 07:46PM
Not if you know what you are doing... my smallest DRSSTC runs at 1.2MHz and produced a 7" spark (3" tall secondary). But, i did have at least 1 IGBT failure, with an unknown cause.
HVAC_Plz: You have far too many primary turns if you are attempting a SSTC at only 12V. You should only need about 2 primary turns for that coil (i would suggest just 1 turn, but i dont think it would work too well). That would explain the very tiny HV arc. Also, be sure to use a breakout point on that spun toroid! SSTCs dont deal well without a sharp point to spew plasma from.
Steve Ward, Wed Apr 04 2007, 07:46PM
800khz secondary is too high for a DRSSTC,
Not if you know what you are doing... my smallest DRSSTC runs at 1.2MHz and produced a 7" spark (3" tall secondary). But, i did have at least 1 IGBT failure, with an unknown cause.
HVAC_Plz: You have far too many primary turns if you are attempting a SSTC at only 12V. You should only need about 2 primary turns for that coil (i would suggest just 1 turn, but i dont think it would work too well). That would explain the very tiny HV arc. Also, be sure to use a breakout point on that spun toroid! SSTCs dont deal well without a sharp point to spew plasma from.
Re: Tesla Coil Design issues.
Ken M., Wed Apr 04 2007, 09:34PM
We'll after a little bit of research, I noticed a pattern between everyones SSTC's and that was they all used between 2-4 turns, so I dropped the primary down to about 3-4 turns and that made my fet Very displeased and hot to the touch after about 5 secs of run time, but I MAY drop it to 2 turns and see how an AMD CPU heatsink works on it, also with the lower turns my wires I was using on the proto board were getting warm enough to start to smoke and melt/deform the insulation, but if on the new fets that I ordered the tab is source ithink then I'll just apply the +v to the heatsink and let it run threw the tab.
Ken M., Wed Apr 04 2007, 09:34PM
We'll after a little bit of research, I noticed a pattern between everyones SSTC's and that was they all used between 2-4 turns, so I dropped the primary down to about 3-4 turns and that made my fet Very displeased and hot to the touch after about 5 secs of run time, but I MAY drop it to 2 turns and see how an AMD CPU heatsink works on it, also with the lower turns my wires I was using on the proto board were getting warm enough to start to smoke and melt/deform the insulation, but if on the new fets that I ordered the tab is source ithink then I'll just apply the +v to the heatsink and let it run threw the tab.
Re: Tesla Coil Design issues.
Ken M., Fri Apr 06 2007, 10:31PM
OK so I changed my secondary 2 days of hand winding... But it's finished!
However now I think my driver has gone crazy, this is the driver design I'm using
Heres the waveforms I'm getting though
when I connect the primary it loads down the power supply (which is to be expected or at least i think would be) but I can't even get it to light up a little neon light bulb.
Ken M., Fri Apr 06 2007, 10:31PM
OK so I changed my secondary 2 days of hand winding... But it's finished!
However now I think my driver has gone crazy, this is the driver design I'm using
Heres the waveforms I'm getting though
when I connect the primary it loads down the power supply (which is to be expected or at least i think would be) but I can't even get it to light up a little neon light bulb.
Re: Tesla Coil Design issues.
Ken M., Sat Apr 07 2007, 07:23AM
I'll Probly get this post locked but its ok I got the coil to work with 12v's I posted it in the "Add your Tesla Coil here", and thanks to Steve Ward, Frikraqq, Bennem, I think EastvoltR posted as wel, and thanks to anyone else who helped that I forogt to mention! (Side note The 4420 chip was sub'd for a 4429!)
Ken M., Sat Apr 07 2007, 07:23AM
I'll Probly get this post locked but its ok I got the coil to work with 12v's I posted it in the "Add your Tesla Coil here", and thanks to Steve Ward, Frikraqq, Bennem, I think EastvoltR posted as wel, and thanks to anyone else who helped that I forogt to mention! (Side note The 4420 chip was sub'd for a 4429!)
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