[TCML] Primary Capacitance Calculations - "Black Boxes"

[Bert Hickman]

Hi Kurt,

Over the years a number of cap autopsies were done, including some 
x-rays. However, the best I can recall was a paper prepared by Dr. Mark 
Rzeszotarski that had x-rays of a large variety of different types of 
capacitor including Maxwell and Plastic Capacitors. His 11 page paper 
can be downloaded from here:

http://www.capturedlightning.com/photos/HVStuff/CAP_XRAY.pdf

Note that, because of the large number of images, this is a fairly large 
file (~15.1 MB)

Bert
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Kurt Schraner wrote:
> I seem to remember Maxwell pulse caps to be internally buildt as MMC's.
> Unfortunately cannot find the link to the TCML postings, which showed
> an autopsy or/and X-ray of a Maxwell cap (...by Bert H. or Terry F.?).
> Someone remembering too?
>
> I've yet some pic's of a Maxwell 37667 autopsy from Kreso Bukvic 08/04/2004
>
> Regards, Kurt
>
>
> Gary Lau wrote:
>> I don't think that the stray lead inductance from an MMC array in any
>> way would impact performance. It may be true that an MMC will have a
>> higher inductance than a purpose-built pulse cap, but this in no way
>> limits performance in our application. If there's an additional few
>> nanoHenrys of lead inductance introduced by the cap leads, just reduce
>> your primary tap position so that the same net inductance and resonant
>> frequency is achieved. Yes, the parasitic inductance is off-axis so
>> the pri-sec coupling will theoretically be slightly reduced, but that
>> too is easily compensated for (if it was significant) by lowering the
>> secondary. Peak currents are unaffected.
>>
>> There may be other reasons that an MMC is not the best choice for a
>> large coil (economics, size, labor, cost, current rating, etc) , but
>> please let's be accurate in citing reasons. Now if you were talking
>> about ESR (Resistance), that would matter, but I've seen no data on
>> that.
>>
>> How can you say in general terms that an MMC is rated for only 432A
>> Peak without stating the construction details (how many parallel
>> strings)?
>>
>> Regards, Gary Lau
>> MA, USA
>>
>>
>>
>> On Tue, Apr 13, 2010 at 12:04 PM, DC Cox <resonance at wildblue.net>
>> wrote:
>>> Using MMCs with a pole xmfr will present problems. Too many lead
>>> connections lead to high relative inductance thus limiting peak
>>> currents in the discharge cycle. Also, MMCs are not designed to
>>> handle the large peak currents.
>>>
>>> Best to use a hi-Q factor energy discharge cap rated to do the job
>>> ---- minimal internal connections that are accomplished with the
>>> extended foil design connections. Typical is a wide foil area with
>>> very low inductance connections which permit high peak currents.
>>>
>>> A typical pole xmfr powered coil, operating with a .06 uF 80 kV
>>> energy discharge capacitor will see peak currents of 3,500 Amps (or
>>> more) in the discharge cycle. Typically these pulses occur at around
>>> 400 pulses per second for best coil performance which again would be
>>> a serious strain for an MMC which is rated at 432 Amps peak (max).
>>>
>>> Dr. Resonance
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