Re: MMC Problems!

["Calvin Patrick" <linhack_tux-at-yahoo-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Not sure about your explosion problem, but since caps
hold charges, sometimes for a long time, even when
shorted could explain you after shutoff failures. 
also, realize you could have alot of current going
thrugh the caps, as a cap will only charge to the
suplied voltage, but the current will continue to
rise.
Calvin
--- Tesla List <tesla-at-pupman-dot-com> wrote:
> Original Poster: "Arthur Mavros" <mpiece-at-one-dot-net.au>
> 
> 
> Hi all,
>         I have just completed building a MMC and I
> am having major problems.
> The caps are WIMA MKP-10's 8.2nf 2000vdc/700vac. I
> am running these as follows.
> 15 in series=0.00054uf (30,000vdc)
> 12 strings=0.0065uf   (matched to NST)
> 15 strings=0.0081uf   (LTR to NST)
> Power supply is one 15kv/30ma NST.
> Spark gap is variable ,8-12 gaps 25thou each ,vacuum
> motor quenched(variable).
> I have safety gaps+NST protection caps on each HV
> leg.
> All MMC caps have 10 meg 1/2 watt resistors across
> each cap.Each cap is
> soldered to the next with solid copper wire 1mm
> thick.
> The caps are mounted on Perspex with each string
> bolted to a thick 15mm wide
> brass strap. This is mounted in a wooden box with a
> fan for extra cooling. I
> thought that this set-up should be very
> durable.(WRONG)
>  
> As soon as I applied the power 1 or 2 of the caps
> went Bang.
> I checked for poor soldering or cross arcing but
> nothing, so I replaced the
> burnt caps only to have the same problem continue!
> The funny thing is that some
> of the caps have gone bang as much as 1 minute after
> shutdown, I cannot
> understand why if they have bleed resistors across
> each of them?
>  
> Your help with this problem would be most
> appreciated as I am at a loss.
> First Light is so close!
>  
>                                            Thanks in
> advance,
>                                                     
>          Arthur.
>  
>                                  
> 
> 


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