Re: [TCML] secondary size, and caps

["DC Cox" <resonance@xxxxxxxxxxxx>]

VDC is Volts Direct Current.  Your VDC value should be equal to 2.5 x Erms
(voltage rating of your nst).  With a 9 kV 30 mA nst, the correct rating
would be 9,000 x 2.5 = 22,500 Volts DC (pulse) rating for the series cap
bank.  Yes, the MMC caps run fine on AC provided by an nst.  You should use
a minimum of 12 MMC caps in a series string, which gives .0125 uF (12.5 nF)
at 24 kV DC --- a safe margin above the 22.5 kV DC rating required.

The shorter coil will see slightly decreased performance, approx 7% in spark
length.

I stock MMC caps if you need them.  Contact me off list.

It's also a good idea to spacewind the last 2 turns on the top end of the
sec coil.  This slowly reduces the capacitance and removes some of the
stress off the last turn.  Just space it the thickness of the wire using
string and then remove this spacer after the AC-43 has begun to set up
(before it gets totally hard.

Dr. Resonance




On Thu, Jul 3, 2008 at 10:38 AM, Nicholas J. Goble <ngoble@xxxxxxx> wrote:

> I have a few more questions.
>
> I'm using a 9/30 NST.  I originally wanted to have a 4" diameter, 20"
> tall secondary, but after a wire shortage, I only have a 17.5" tall
> secondary.  Will this make a difference in my overall coil performance?
>  If so, how much difference will it make?  If I splice the wire and add
> on another 2.5", will that do anything?  I read that the coil was
> supposed to be continuous.
>
> I want to build my MMC and I've been told that I should just use a
> bunch of 942C20P15K-F caps.  I've asked this before (Designing an MMC),
> and I got a lot of questions answered.  I now understand how voltage
> works on the MMC, but I'm still confused as to what my capacitance
> should be.  I know I should shoot for 120BPS, but I can't find how to
> make that happen.  Could someone explain how to get my BPS to 120 or
> just tell me how many caps (.15mF 2000V) I should put in series to make
> a suitable MMC?
>
> Should I buy the caps listed on this page?  Would they work for me?  I
> know it says 2000VDC and I'm not sure about the "VDC".  I'm not
> building a DC coil.  Does VDC mean DC volts?  Where can I find suitable
> caps to use on an AC coil?
>
> Thanks
>
> Nicholas Goble
> _______________________________________________
> Tesla mailing list
> Tesla@xxxxxxxxxxxxxx
> http://www.pupman.com/mailman/listinfo/tesla
>
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla