Re: Discharging HV Caps

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "Ed Phillips by way of Terry Fritz <twftesla-at-qwest-dot-net>" <evp-at-pacbell-dot-net>

Tesla list wrote:
> 
> Original poster: "Sundog by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<sundog-at-timeship-dot-net>
> 
> ----- Original Message -----
> From: Tesla list <tesla-at-pupman-dot-com>
> To: <tesla-at-pupman-dot-com>
> Sent: Thursday, June 07, 2001 8:55 PM
> Subject: RE: Discharging HV Caps
> 
> > Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>"
> <Gary.Lau-at-compaq-dot-com>
> >
> > >I would think the best way to manually discharge the cap would be by
> > using an
> > >insulated stick of some kind and shorting the spark gap.
> >
> > This sounds appealing in that no potentially-open resistors are needed.
> > But if the cap did contain a significant charge, it would ring up the
> > primary, then the secondary, and odds are that you'd be standing pretty
> > close to or touching the secondary, and....
> >
> Snip!
> 
> Yup! Been there, done that!  Took a sizeable hit to the back of my forearm
> of the arm holding the shorting wand.  It was a roughly 20" spark, hit my
> arm and popped out my foot to the floor.  That was the *last* time I did
> that, and subsequent runs used a string of 10mohm resistors across the
> capacitor.  The coil was a 9/60 powered 2x13" coil, and could throw roughly
> a 30-33" spark on a 13nf tank cap.  Mean little bugger.
> 
> Shad

	The failure mode of most resistors is OPEN!!!!!!!!  Using resistors in
excess of their design voltage ratings just exacerbates the problem!  I
suspect that many of the 10 meg resistors mentioned here have opened up
along the way.  Check the voltage ratings of any parts you use, and keep
within them if you want safe operation.

Ed