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Re: Maxwell

Original poster: "Sean Taylor" <sstaylor@xxxxxxxx>

Rich,

The 25A means 25A RMS throgh the cap.  I don't know what you'll end up
putting through it on average from a certain power supply, but your power
supply may be somewhat close (15 to 20A), though this is just an estimate
on my part.  Dr. Resonance or many others may be able to comment more
directly on this as they have a lot of experience with a lot of different
coils.

25A through the cap is actually quite easy to obtain as the peak currents
from the cap are huge.  You could calculate the RMS current by knowing the
Q of the primary circuit (and where it quenches) - ie the ringdown shape,
and breakrate. If you wanted to be more precise, you could factor in the
charging current as well.  If none of this makes sense to you, check out
Richie Burnett's website for a great explanation of how a Tesla Coil works
(ringdown, etc).

Sean Taylor
Urbana, IL

On Sat, 05 Nov 2005 20:11:10 -0600, Tesla list <tesla@xxxxxxxxxx> wrote:

Original poster: "Rich" <rdjmgmt@xxxxxxxxxx>

Thank you gentlemen for your help, I intend to hold it under 25 amps, I
hope this does not sound dumb but you can't mean 25 amps at the cap. Do
you imply 25 amps into the system? I hope to hold it at less than that.
The transformer is only rated at 1.95Kva or about 150ma ccs and I was
not going to go over that by much.

Rich

Subject: Re: Maxwell

Original poster: Edward Wingate <ewing7@xxxxxxxxxxxxxxxx>

Tesla list wrote:
 >Original poster: "Sean Taylor"
<mailto:sstaylor@xxxxxxxx><sstaylor@xxxxxxxx>
 >
 >Rich,
 >
 >As far as I know, all the 31xxx caps were rated at 1 PPS.  Now, there
are
 >several ratings to consider, the first being voltage.  If you are
 >seriously underrating the voltage (like a 12 kV NST on that cap) you
 >shouldn't have too much of a problem running it at 120 bps, say.  Just
be
 >careful of heating, and don't make your primary too small (lower
 >inductance and higher peak current).
 >
 >FWIW, I got some Maxwell spec sheets a while back from someone on the
 >TCML, and I've put them on my webserver:
 ><http://64.198.215.215/maxwell/>http://64.198.215.215/maxwell/
 >NOW, I'd appreciate it if everyone didn't just go download those for
the
 >heck of it, 'cause I have a limited BW - 600 MB daily.  Thanks!
 >
 >Sean Taylor
 >Urbana, IL
Sean,

Not true. Both the 31393/.06 mfd @ 40 kv and 31976/.075 mfd @ 40 kv
are rated at a continuous rep rate of 100 pps. Keep in mind that's
CONTINOUS rep rate with no stated time limit. The most important
factor is not to exceed the 25 amp RMS current rating as is stated in
the following answer from an engineer at General Atomics/Maxwell to
an inquiry from Phil Labudde about the 31976. The answer Phil got was
similar to a response I got from an inquiry to Maxwell about  the 31393.

"Phil,

Andy Bushnell passed your inquiry along to me.

The original ratings for PN 31976 are given in the attached PDF
file.  We have not built this capacitor for at least 6 years.  It was
originally designed in 1987.

The maximum rep rate is stated as 100 Hz.  In reality, the RMS
current is the limiting factor, and should be kept at 25 Amps or
less.  The rep rate can be higher than 100 Hz as long as the RMS
current rating is not exceeded.

I hope this helps.

Joel"

Ed Wingate RATCB