Re: 18,000. AMP high energy Cap bank

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: Bert Hickman <bert.hickman@xxxxxxxxxx>

Tesla list wrote:

> Original poster: FIFTYGUY@xxxxxxx
> In a message dated 12/17/04 9:14:29 PM Eastern Standard Time, 
> tesla@xxxxxxxxxx writes:
>  >>     How does one limit these current levels? If a energy discharge cap
>  >> system has an ultimate safe rating of (say) 20kA, how does one make sure
>  >> that current isn't exceeded during an experiment that vaporizes a 
> specimen?
> Don't forget that this is a linear system... You can charge the capacitor
> to a lower voltage, close the switch and measure the currents with a 
> conventional oscilloscope.  Then just scale.
>     Is it still a linear system if you vaporize a wire, or discharge 
> through a gas tube? Are small vaporizations linear to higher-energy ones? 
> Or is a good hefty chunk of copper pipe (or other low-inductance load 
> that will survive) a good "worst case short circuit" to presume and work 
> backward from there?
> -Phil LaBudde
>
> .

Phil,

It can be argued that the inclusion of an exploding wire or a spark gap 
switch in the loop will introduce a degree of nonlinearity into the system. 
However, by purposely adding a known robust and fixed inductance between 
the capacitor bank and the load, conservation of energy will still limit 
the worst case short circuit current for a given capacitor bank voltage. 
Since this limit assumes a perfect switch and a zero ohm load, it will be 
the worst case current that can delivered by the capacitor bank (assuming 
no capacitor failures within the bank).

Adding any imperfect switching or nonlinear (but passive) load effects into 
the discharge path can only result in a lower peak current. This is 
analogous to estimating the worst case "bolted fault" short circuit current 
when sizing the interrupting capacity of circuit breakers and fuses in 
commercial electrical power systems.

Best regards,

-- Bert --
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