Re: The Geek Group High Voltage Capacitors, making a HV switch, (fwd)

["High Voltage list" <hvlist@xxxxxxxxxx>]

Original poster: Steven Roys <sroys@xxxxxxxxxx>



---------- Forwarded message ----------
Date: Tue, 7 Nov 2006 16:44:54 EST
From: Mddeming@xxxxxxx
To: hvlist@xxxxxxxxxx
Subject: Re: The Geek Group High Voltage Capacitors, making a HV  switch,
      (fwd)

 
In a message dated 11/7/06 10:39:46 A.M. Eastern Standard Time,  
hvlist@xxxxxxxxxx writes:


>
>The short circuit energy in these capacitors cannot be  adequately
>described in an email. They will not give you a second  chance... never,
>ever, forget  this.
>
>Bert
>--



Hi All,
 
I have been talking with a friend of mine who spent 35 years in explosives  
testing and development about the proposed Geek Group bank of 20 of these caps. 
 His response was:
 

>     Matt,
>
>     The 20  capacitors store the equivalent energy of 1/2 pound of TNT. 
>   That's about one hand grenade's worth.
>
>   Keith
>

We have been arguing about whether total energy is  a meaningful measure in 
safety considerations for protective  enclosures, since the chemical reaction 
of a typical explosion takes 5-10  ms to go to completion, but the time 
constant for these caps could be a lot  shorter.
 For example: A 200 KJ discharge in one second is 200 kW peak power,  but the 
same discharge in 10 msec is 20 MW and if the discharge were  in 10 usec it 
would be 20 GW peak !!
There are two sources of destructive capability in a cap bank. One is  
equipment fragmentation, the other is the shock wave from the  plasmalyzation of the 
air. It makes the designing for safety without  over-designing interesting. 
In coin shrinkers, of course, the hope is that  most of the energy goes into 
the EMP. 
 
Matt D.