Re: MMC vs Maxwell comparison

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

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



66.67 Mohms of drain resistance dissipates about 1.2 watts (9000 VAC) which
is actually about 0.5% of the coil's power (~225 watts).  Your testing may
actually be sensitive enough to see that!



Terry,

Thanks for your analysis, and all your other analyses and MMC
promotion over the years.  I'm not sure just how warm they're getting.
It's possible that I'm just simply used to dealing with the massive
Maxwells which take forever to heat up.  The only other MMC I
remember seeing was Sue G's, and they seemed to run much
cooler on her 6/60 NST coil.  It is likely that mine were warming
in compliance with your calcs and tests though.  Not a problem.
I may install an MMC onto the TT-42 TC also, to make it lighter,
since it's a portable coil.  I have to get back to the STSG work
too.  Much to do.

Cheers,
John


>
> I am a little surprised at your mention of how "quickly" the MMC heated up.
> I assume the temperature was less than 10C.  Your configuration should be
> able to easily handle the current so I am a little surprised if they got
> "very" warm.  I would guess they would heat to about 4C after a very long
> run.  Your coil probably runs about 5 amps RMS in the primary.  You
> mentioned a couple of minutes of intermittent run time so maybe the 4C is
> just about what you are seeing.  
> Probably the leads, dissipation, and drain resistors do have more loss than
> the Maxwell.  10 Geek Group caps would be about the equivalent for $30.  If
> we can get to 99% of a Maxwell cap for $30 (I don't know what Maxwell's
> cost) I guess we do real good :-))  It's interesting that MMCs were
> inspired to find a primary cap that would stand up in situations that
> failed Maxwell caps.  Of course, we know far more about primary currents
> now which was the key there.  One other giant advantage is that MMCs can
> survive short over voltage events.  Maxwells get "messy" with over voltage! 
>
> Wonderful testing you did here!!  I am surprised you could see such a fine
> difference.  The results sound just right and would agree with the numbers
> involved.  Glad you "finally" got an MMC ;-))
>
> Great test!!
>
> Cheers,
>
>     Terry
>