Re: MMC ratings

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

Original poster: "Terry Fritz" <twftesla-at-qwest-dot-net>

Hi Mark,

Just for the record, I think the Geek group MMC chart you made is wonderful 
and I fully endorse it!!  I use it all the time since a chart stuck to the 
side of the PC is far faster than any program ;-)

Cheers,

         Terry



At 11:35 PM 11/30/2002 -0600, you wrote:
> >Geek group caps have been tested to 5700 volts before breakdown and then
> >they self heal and are good to go again.  Panasonics go to 3600 volts.  I
> >really don't feel the voltage is a problem at all with MMC caps.  The real
> >area of concern is current and internal heating.
>
>The only failure I'm aware of, aside from Chris Robert's, was attributed 
>to overcurrent.  That
>was about 18 months ago, and I can't recall a single detail about it since 
>I was on vacation
>at the time. :(
>
>In my last email, the third failure was Terry's destructive testing of a 
>cap we sent him,
>shown in the quoted link below.
>
> >http://hot-streamer-dot-com/TeslaCoils/MMCInfo/mmcinfo.htm
> >
> >I used to send a printed copy with each MMC cap order in the good o'l
> >days.  I also sent along 10Meg resistors for free that were also trouble
> >free over the years.
>
>I believe the MMC sales page on our site has a copy of that sheet.
>
>
> >"I" would run Geek caps to 4000Vpeak in an EEMMC design and I bet they
> >would work just fine ;-))  I also bet I know a few things about poly caps
> >that most of the manufactures don't know :-))  However, Cornell Dubilier
> >has done a few tricks to extend the art even further!
>
>Likewise, for my own coil, I would use 2500 to 3000V, since I'm not as 
>daring as Terry. ;)
>But for a coil I would build or design for someone else, I would use no 
>less than what is on
>the MMC Design chart I put together.
>
>I believe there are plans to replace the design chart with a Javascript 
>design calculator with
>a selectable "ratings" option.  This will also allow the design to be 
>scruitinized for current,
>which isn't really possible in a static chart.
>
>One of these days I'll tear apart one of these caps to learn firsthand 
>these "tricks" CDE
>uses. ;)
>
>The GeekMMC Design Chart was created using the "generally accepted" 
>voltage ratings for
>MMCs and MMC caps.  Since the CDE caps test better than the Panasonics, I 
>would
>argue that the GeekMMC Design Chart actually has better voltage ratings 
>than an
>equivalent design using Panasonic caps.
>
>Mark Broker
>Chief Engineer, The Geek Group