Re: MMC vs. Maxwell caps?

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <Mddeming-at-aol-dot-com>

In a message dated 4/24/01 7:20:07 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes: 


>
> Original poster: "Bill Vanyo by way of Terry Fritz <twftesla-at-uswest-dot-net>" < 
> vanyo-at-echoes-dot-net> 
>
> I'm building my first coil, somewhat medium size.   
>
> The primary and secondary are done already (secondary is 6.5" by 27.5", 
> 1000 turns of 22 awg, primary is 19.5 turns of 1/4" copper tubing, 1/2" 
> spacing on centers, inside diameter 9.5").  Also have NST protection 
> circuit complete (using plan from Terry).   
>
> I'm planning on using 2 or 3 15/60 NST's, and going LTR with a static 
> gap, so I'll need 0.030uf or 0.045uf 
>
> Now, I'm debating whether I should do an MMC, or try some of the Maxwell 
> caps available here (near bottom of page): 
>
> http://www.teslasystems-dot-com/products/index.html 
>
> I know everybody loves MMC's, but these Maxwell caps appear more cost 
> effective to me - a 0.03uf cap, rated 35kvdc, goes for $85.  I'd still 
> be stuck with no cheap way to get 0.045uf - it would be cheaper to get 
> 0.06uf (2 of these maxwell caps) and a 4th 15/60 NST, but 4 15/60 NST's 
> might be enough to scare the neighbors (I'm stuck with running it 
> outdoors - house has low ceilings). 
>
> So, does anyone see any drawbacks to using these Maxwell caps?  Am I 
> wrong about it being cheaper to use one of these for 0.03uf than to 
> build an equivalent MMC? 
>
>    Thanks, 
>    Bill Vanyo



Hi Bill! 
        When purchasing Maxwells, (I have 3), you never know their prior 
history, ergo you never know their remaining life expectancy. It is finite. 
        Some have a plastic screw as a "filler plug"  these occasionally 
leak during shipping or they leaked before shipping and weren't topped up. 
        If one cap in an MMC goes south, you're out less than $2.00. With a 
Maxwell, it's the whole enchilada or nothing. 
        If you purchase a Maxwell from a known good source, you know it 
hasn't seen a lot of heavy service, you know it has been properly maintained, 
and you are not the kind who likes to push the ratings envelope real hard, 
then they are fine. 
Otherwise stick with a MMC. 

My 1/50 of a dollar. 

Matt D.