Re: MMC advice

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


If you run the DC cap rating as the AC cap rating you will have trouble and
problems --- as you are experiencing.

Rate the AC cap string at least twice (preferably 2.5) times the DC cap
rating and you can get away with it on short duty cycles.  We rate our MMC
cap strings for AC rating at 3 times DC rating --- and we can run a coil for
15 minutes or more continuous without any failures.

Once you start damaging a cap here and a cap there you really don't have any
solid reference point because with several caps you would have to test the
leakage current on each cap at it's rating potential to find your problem
caps.  If you overrate them for AC use at least 2.5 times their DC rating
you should not have any future problems.

I know many experimenters get away with less --- but, hey --- it's the last
straw that breaks the camels back, and in this case --- you can't see it
happening.  Also, it always seems to happen when you want your system to
work to show off to someone --- that's when it will fail.

Using new caps and good engineering to start with can save a lot of
headaches down the road.  At only $3.00 per cap it's the best cap bargain
going.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913

 > Original poster: Thomas <tom-at-pwrcom-dot-com.au>
 >
 > Have you tried the MMC calculation spreadsheet?:
 >
 > http://www.pupman-dot-com/listarchives/2002/April/msg00146.html
 >
 >
 > I use identical capacitors (RS 114-468) in an 18 x 18 array with 10M
 > bleeders, this is (nearly) resonant with an 11kV 80mA NST (50Hz).
 >
 >