[Prev][Next][Index][Thread]

Re: Success with PP Multi-Mini Cap



Hi Dave and all,

> Original Poster: David Trimmell <davidt-at-pond-dot-net> 
> 
> Hello Reinhard and all,
> 
> You and many others on this list do seem to be getting very good results
> using the MMC method. I was only thinking that the wire diameter of the
> leads would be thin, unless you are paralleling many. With, potentially,
> hundreds of amps going through these I would look for the weakest link. My
> commercial Cap from Condenser Products Co. uses 5 or 6 (cant remember
> which) individual caps in series, all are designed with extended foil for
> low resistance. I also use a series string of Philips Polyprop caps for my
> Tube coils, and they work very well. The real proof is in the performance,
> though.  
> 
> I would be interested in what power levels these MMC's have been used at,
> anyone use them in a >2KW coil yet? Also a price comparison with available
> commercial caps would be interesting. I seem to remember that a MMC of
> around 0.02 uFd at, say 15KVAC, would cost around $130 to $160 USD, I
> think? What is available on the commercial market for a pulse cap of like
> ratings? My Condenser Products cap cost $160, but I understand they no
> longer sell for Tesla coil use. My list of cap suppliers is out of date,
> anyone got an updated one? Perhaps I could check price ranges. 
> 
> Regards,
> 
> David Trimmell

Since the I^2.R losses are the concern, it is worth noting that as 
wiring and leads get shorter, it is common practice to push the 
current density in a piece of wire to ever higher levels. This is 
commonly done in switchmode transformers where windings consist of 
just a few turns. The decrease in wire area is compensated for by a 
drop in length. Ultimately I think the internal connection area in 
the caps themselves is going to define a safe current limit.

Malcolm