Re: [TCML] 8 inch tesla coil design

[DC Cox <resonance@xxxxxxxxxxxx>]

I seldom exceed 0.130" while tuning, and then 0.180" after tuning --- that
is total max for all sparkgaps combined when running with nsts.  Long happy
life on all components.

DC




On Fri, Sep 10, 2010 at 4:14 PM, David Rieben <drieben@xxxxxxxxxxx> wrote:

> Jeremy,
>
> As DC mentioned, you may get a erratic firing out of a STATIC
> spark gap with that much C from a 15/120 NST power supply.
> If you were using a SRSG, then you could go considerably higher
> into the LTR zone without suffering this effect and consequently,
> get longer output sparks. Since you are using a static gap, you defnitely
> want to stay away from near resonant size with you primary cap
> as the R voltage rise can make a boat anchor out of your NST in
> short order, especially if you open the primary SG too wide!
> Then again, if everyone used restraint and kept their SGs narrowed
> to a reasonable width that was comensurate with the rated output
> voltage of the NST, it seems that there should not be a problem
> with ressonant voltage rise smoking the transformer (or the capacitor).
> Of course, for coilers, that is obviously a tall order, though. ;^)
>
> David Rieben
>
>
>
>
>
> ----- Original Message ----- From: <jeremyee@xxxxxxxx>
> To: "Tesla List" <tesla@xxxxxxxxxx>
> Sent: Thursday, September 09, 2010 9:30 PM
> Subject: Re: [TCML] 8 inch tesla coil design
>
>
> So the rule of thumb of using only a 3:1 aspect ratio for secondary
>> diameters of 8 inches or more is no longer recommended? It has been several
>> years since I looked at this. Thanks for the input.
>>
>> Also, David, I am using an MMC and to up the capacitance I could put
>> another string in there. It would raise the capacitance from 30 nF to 45 nF.
>> Can an NST handle charging this load or will I get erratic behavior out of
>> my static gap?  The LTR recommended for my power supply is about 35 nF.
>> Thanks again for the inputs!
>>
>> Jeremy
>> Sent from my BlackBerry device from Cincinnati Bell Wireless
>>
>> -----Original Message-----
>> From: DC Cox <resonance@xxxxxxxxxxxx>
>> Sender: tesla-bounces@xxxxxxxxxx
>> Date: Thu, 9 Sep 2010 14:22:43
>> To: Tesla Coil Mailing List<tesla@xxxxxxxxxx>
>> Reply-To: Tesla Coil Mailing List <tesla@xxxxxxxxxx>
>> Subject: Re: [TCML] 8 inch tesla coil design
>>
>> 3.5:1 is ok.  4.5:1 will provide better performance.
>>
>> I usually shoot for 10-12 turn pri, so you might wish to add a small
>> amount
>> of capacitance, but your 14 turn pri should also work very well.
>>
>> Dr. Resonance
>>
>>
>>
>>
>> On Wed, Sep 8, 2010 at 7:59 PM, <jeremyee@xxxxxxxx> wrote:
>>
>> Hey group. It has been a long time since I have been on here and I wanted
>>> to pass a design by you guys to see if I have anything weird. Below are
>>> some
>>> inputs to and outputs from TeslaMap:
>>>
>>> 15 kV, 120 mA NST bank
>>> 30 nF MMC
>>> 8.625 inch secondary with 1160 turns of #23 magnet wire (74 mH)
>>> 6 in by 30 in toroid (31.6 pF)
>>> Tuned primary at 14 turns for 112 uH
>>> Resonant at 87 kHz
>>>
>>> One of my main concerns is sizing the toroid for maximum breakout voltage
>>> but keeping the number of primary turns down to minimize resistive
>>> losses.
>>> At 14 turns I feel like I am a little too high. I am using a static gap
>>> with
>>> about 6 parallel copper couplings. My secondary aspect ratio is about
>>> 3.5:1
>>> (is this ok?). I really appreciate any insight into my design. Thanks!
>>>
>>> Jeremy
>>> Cincinnati, OH
>>> Sent from my BlackBerry device from Cincinnati Bell Wireless
>>> _______________________________________________
>>> Tesla mailing list
>>> Tesla@xxxxxxxxxx
>>> http://www.pupman.com/mailman/listinfo/tesla
>>>
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>>
>
>
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