Re: Old Capacitors

From: 	Alfred A. Skrocki[SMTP:alfred.skrocki-at-cybernetworking-dot-com]
Sent: 	Wednesday, December 03, 1997 2:18 PM
To: 	Tesla List
Subject: 	Re: Old Capacitors

On Monday, December 01, 1997 4:46 AM Alan Sharp
[SMTP:100624.504-at-compuserve-dot-com] wrote;

> Greetings all,
> I've just aquired six 0.1uf 10kv DC capacitors.
> They are 7" long, 1" diameter brown cylinders with stud terminals
> marked Hivoltage Capacitors Limited
> Londonderry N.Ireland
> +8% ripple 50Hz
> TPM 100-114
> I was going to put 3 of these in series,
> then 2 series in //  for my 7.5KV AC 550mA supply - to give 0.066uf 30kV DC
> but I'm wondering if they will take the current at 200kHz -
> would I be better to use 4 or 5 in series and get the other 0.04uF from
> my other capacitors? Or reduce the voltage to 5kV AC.
> It also occurs to me that moving to a lower frequency - bigger coil
> will ease the load on the capacitors.
> Any thoughts.

You have a mixed set of possible conditions there. One one hand it is very 
well possible that your 10 Kv caps may hold up fine at the 7.5 Kv usage you 
have in mind, this would allow you to put all 6 in parallel to yield a 
total capacitance of 0.6 ufd. For safety you could maybe double up on them 
rather than tripleing up on them as you were, the 2 in series giving
0.05 ufd. and then putting the three sets of these in parallel to give a 
total capacitance of 0.15 ufd. I wouldn't put any more in series unless you 
NEEDED the smaller capacitance values. The idea of putting 4, 5 or more
capacitors in series, unless you need those values, seems like a lot of 
work for no reason. I see no rerason to lower your voltage given the 
capacitors you now have.


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                           Alfred A. Skrocki
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