Re: M.M.C.

[Terry Fritz <twftesla-at-uswest-dot-net>]

Hi Al,

	I need to know some details:

What frequency does you coil run at?  Poly caps heat more at higher
frequencies so they have to be sized to the frequency if one is trying to
be really careful.

What type of gap do you have.  The RMS current is directly propartional to
the firing rate.  I assume the firing voltage is about 21kV.

If you know the values of cap you want that helps ;-))

There is a simple BASIC DOS program below that can do the calculations for
you too:

http://users.better-dot-org/tfritz/site/programs/MMCCALC2.ZIP

The numbers change a bit depending on the exact type, value, and
manufacturer of cap you use.  I use ones from DigiKey which I know well,
but there are all kinds of great caps. 

Check the links in these posts out and let me know the data about your coil
and we can work the numbers.  If the voltage peak is within the DC rating
and the RMS current does not heat them more than 5C, they will last
thousands of hours...

At 11:40 AM 9/6/00 -0400, you wrote:
>Hi Terry and all.  Terry, what kind of polypropylene caps would you
>recommend for a coil using two paralleled 15kv-at-60ma modified neons that
>could sustain a minimum of a 60 minute run?  They draw 16 amps at full
>output but limited by 4500w 240v water tank elements.   At full blast
>with no resistive load they will pop a 20 amp breaker after about 10 to
>15 minutes, I guess from the heating effect on the 20a. line.  So I run
>them on a separate 30a. 10 ga. 120v. line to get sustained runs.    
>Thank you  Al.
>