Re: Capacitor Safety Discharge (my system) (fwd)

["Tesla list" <tesla@xxxxxxxxxx>]

---------- Forwarded message ----------
Date: Thu, 9 Aug 2007 03:45:16 -0700 (PDT)
From: Yurtle Turtle <yurtle_t@xxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>
Subject: Re: Capacitor Safety Discharge (my system) (fwd)

I have two 10/100 5 kJ Maxwell caps that I use for
coin shrinking, exploding wire, exploding vegetables,
etc. After a shot, I bleed the caps down with a bleed
resister, then I place a 4" x 1/4" piece of bus bar
across them, before unloading/reloading. I keep this
shorting bar in place at all times, except when in
use.

Adam

--- Tesla list <tesla@xxxxxxxxxx> wrote:

> 
> ---------- Forwarded message ----------
> Date: Thu, 9 Aug 2007 07:57:14 +0800
> From: Peter Terren <pterren@xxxxxxxxxxxx>
> To: Tesla list <tesla@xxxxxxxxxx>
> Subject: Re: Capacitor Safety Discharge (my system)
> 
> I run a pulse cap bank for exploding wire, coin
> shrinking, pyrotechnics and 
> general mayhem. It is a 16kJ capable bank which I
> have only ever run to 5kJ. 
> Since I bolt things on and off the main electrodes
> frequently, I need to be 
> 100% sure of discharge.
> I have the following:
> A group of 4 neons connected via a resistor chain
> gives a bright visual 
> indication of voltage but will extinguish at perhaps
> 200V
> A single neon relaxation oscillator that flashes
> with voltage down to 70V
> A meter showing total voltage
> A shorting strap attached to a ? 60K 20W resistor
> A spanner as a final pre-touch check.
> 
> I get nervous particularly when I am doing shots
> that don't give full 
> discharge. You don't want to rely on one method
> alone if it is truly life 
> threatening as this is.  I don't have a continuously
> connected bleeder 
> resistor but leave the shorting strap with 60K
> resistor connected when not 
> in use to prevent the recovered charge which would
> otherwise go to several 
> hundred volts.
> 
> Peter
> http://tesladownunder.com
> 
> >
> > ---------- Forwarded message ----------
> > Date: Wed, 8 Aug 2007 12:12:24 -0700
> > From: Ray von Postel <vonpostel@xxxxxxxxxxx>
> > To: Tesla list <tesla@xxxxxxxxxx>
> > Subject: Re: Capacitor Safety Discharge Method
> (fwd)
> >
> > Jim:
> > Sorry, your logic still escapes me.  How fast is
> the capacitor
> > discharged if a resistor is open?   Yes, as you
> point out "There is a
> > world of difference....", but what has that to do
> with safety?  I do
> > not accept that there is any safe level of voltage
> when it comes to
> > safety.  Perhaps you would care to state what
> voltage level is safe
> > under all conditions but I don't.
> >
> > The bottom line is that resistors are fallible
> just as are O rings.
> > Don't trust your life to them nor advocate
> something that could and has
> > killed some one.
> >
> > The best safety device I know of is a suitable
> length of bare copper
> > braid such as sometimes used to connect storage
> batteries, one end
> > bolted permanently to one side of the capacitor
> bank (Ground?) and the
> > other end attached with a mechanical fastener to a
> 1/4 inch brass rod
> > bent with a hook on the end.  The brass rod is an
> extension on about 3
> > feet of insulating plastic or fiber rod to use as
> a handle. It is easy
> > to see that something like that is in working
> condition.  So it goes
> > flash crackle pop.  So what if it keeps you or
> some one else from
> > getting killed?
> >
> > I have had my say.  Now if anyone gets hurt
> because they refused to
> > heed this waring they certainly deserve the
> appellation for which D.C.
> > suffered flames, IDIOT!!!
> >
> > Ray
> >
> > On Aug 7, 2007, at 3:30 PM, Tesla list wrote:
> >
> >>
> >> ---------- Forwarded message ----------
> >> Date: Tue, 07 Aug 2007 15:27:37 -0700
> >> From: Jim Lux <jimlux@xxxxxxxxxxxxx>
> >> To: Tesla list <tesla@xxxxxxxxxx>
> >> Subject: Re: Capacitor Safety Discharge Method
> (fwd)
> >>
> >> At 05:51 AM 8/7/2007, you wrote:
> >>
> >>> ---------- Forwarded message ----------
> >>> Date: Mon, 6 Aug 2007 21:45:35 -0700
> >>> From: Ray von Postel <vonpostel@xxxxxxxxxxx>
> >>> To: Tesla list <tesla@xxxxxxxxxx>
> >>> Subject: Re: Capacitor Safety Discharge Method
> (fwd)
> >>>
> >>> Guys:
> >>>
> >>> You are shorting out capacitors to keep from
> frying yourselves. What
> >>> is
> >>> the safety logic of putting some resistors in
> the circuit?
> >>
> >>
> >> Small resistors limit the current when
> discharging, while still
> >> getting the voltage low enough, quick enough, to
> be safe.  There's a
> >> world of difference between dumping hundreds of
> joules in 1
> >> millisecond vs dumping it in 1 second.
> >>
> >>
> >>
> >>
> >>
> >
> >
> > 
> 
> 
> 
> 



      ____________________________________________________________________________________
Park yourself in front of a world of choices in alternative vehicles. Visit the Yahoo! Auto Green Center.
http://autos.yahoo.com/green_center/