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Re: MMC Survivability



Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

I don't think the MMC's would have a problem with the high rep rates (at least the 500 pps mark). I think the real advantage to the Maxwells are their robust design from a voltage and energy look. Any cap can die from poor design of the application, but when the cap is rated for the task at hand, the right Maxwell cap is a good choice for high powered systems.

For the smaller systems (of which there are many), the MMC's are perfect! But when getting into serious high power, professional pulse caps have their place. Until a new MMC cap of larger value is designed, professional pulse caps are the way to go, well, unless money is no object (of which I've never seen).

Take care,
Bart

Tesla list wrote:

Original poster: "resonance" <resonance@xxxxxxxxxxxx>


One major advantage to using the Maxwells is that you can run 450-480 bks/sec which dramatically increases sec output spark length over a 200 bks/sec RSG rate. I'm not sure if the MMCs would handle 480 pps.

Dr. Resonance


----- Original Message ----- From: "Tesla list" <tesla@xxxxxxxxxx>
To: <tesla@xxxxxxxxxx>
Sent: Tuesday, August 29, 2006 12:12 AM
Subject: Re: MMC Survivability


Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Bart,

If biased at 5KVA, Cres should be 64nf. If Jim was running at 120BPS, his output voltage would be very high. Since he is at 200BPS, I think this value will be OK. My simulations (since I'm sorta in the same boat with my 5KVA pig) shows that with 240 BPS, I can go down to 75nf and still keep the voltage reasonably under control. I'm planning to go as high as 130nf to test 120 BPS so I will monitor my voltage rise. To be on the safe side, Jim could do a spice on his charging ckt with 200BPS and see what the voltage rise is. I could even do that if he wants.

Gerry R.

Original poster: "Barton B. Anderson" <bartb@xxxxxxxxxxxxxxxx>

Hi Jim,

I suspect it will perform great! The voltage
standoff capability is low, but these are MMC's.
If you are running in a healthy LTR mode, you
would be fine. However, 0.1uF is not a healthy
LTR mode for your pig. It's kind of near the
static gap LTR value. I suspect you'll be using
an RSG of some type. You will be on the ragged
edge of "ok" and "slightly possible to overvolt a
cap" (which I have done with MMC's). Considering
the "costs" your looking at, another $100 could be good insurance.

If you were me however, you wouldn't spend the
extra cash. You would try to get away with the
minimum caps required. After all, when a cap
blows, it won't be a $500 nightmare. It will be a
$3 setback. That's what is nice about MMC's. If
you do this right, you won't need a professional
pulse cap, but doing it right doesn't have to be
perfect the 1st time round. At little costs, you
can simply add caps to the strings as necessary.
I eventually ended up with an 18 string cap bank,
but only after blowing up a 15 string (only 1 cap
died, so no big deal. And that is the coolness of MMC's)!

BTW, I run both MMC and Professional Polystyrene
pulse caps. They both perform well. I can't
really see a difference between the two from a
performance basis. But when it comes to cost,
MMC's are always the winner. Not always up front
cost, but certainly maintenance cost.

Take care,
Bart

Tesla list wrote:

Original poster: "Jim Mora" <jmora@xxxxxxxxxxx>

Hello all,

I'm building a 12" coil powered by a 5KVA 14.4kv (pushed a bit). I had hoped to buy one of Dr R's Maxwell super caps but the buy won't go through until next spring.

What do you think the survivability of 10 rows (.1uf) of CD942C .15uf, 2000kv x 15 strings and a 200 BPS ASRG will be, since I have that many?

Thanks, I suspect it would be on the edge.

Jim Mora