Re: Cap Safety

To: tesla-at-pupman-dot-com
Subject: Re: Cap Safety
From: "B**2" <bensonbd-at-erols-dot-com> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)
Date: Sat, 01 May 1999 23:29:43 -0600
Approved: twftesla-at-uswest-dot-net
Delivered-To: fixup-tesla-at-pupman-dot-com-at-fixme
Hi Brent, All,
    I wouldn't use it, ever!  I prefer a shorting stick consisting of
a shepard's hook of 1" brass strap connected to a long insulated pole.
The hook is connected to system earth ground with a piece of heavy
braid.  The first step in my safeing procedure is to check all system
grounds for continuity and then disconnect and interlock all external
energy sources. Next I put on safety goggles and ear protectors.  Then
I check to see that the shorting stick ground is connected to ground
(rembering Cockroft and Walton).  I now touch all points on the system
to make sure all energy storage sources are discharged, working from
the low potential end of the system to the high potential end. This is
to ensure that I am as far away as possible should a heavy discharge
to ground occur.  I now start over at the low potential end of the
system.  This time as a point is touched with the shorting stick it is
also hard grounded with a clip lead.  Working toward the high
potential end of the system each point is in turn touched with the
shorting stick and then grounded with a clip lead. When finished the
shorting stick is hung from the highest potential point of the
generator (the 2.5 MegaVolt Marx has a 20 foot long shorting stick!).
All connections are visually rechecked.  On a large Marx I may spend
several minutes visually rechecking the grounds before allowing test
personnel to enter the area.

     Be safe.




----- Original Message -----
From: Tesla List <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Tuesday, April 27, 1999 7:01 PM
Subject: Re: Cap Safety


Original Poster: Brent L Caldwell <stretchmonster-at-juno-dot-com>


Terry Fritz, Adam, and all:

Regarding the topic of getting jolts from partially charged caps, I
was
wondering about a certain practice I use to discharge my tank cap.  I
have two pieces of 1" dia. PVC pipe, each about 3' long.  A piece of
stranded wire is strung and taped from the tip of one pipe to the tip
of
the other, to make a contraption that resembles a ninja's nunchuckas
in a
way. :-)  Each end of the stranded wire is exposed.  To discharge the
capacitor, I use this wire, holding by the PVC handles, to short out
the
cap.
A technichian who works high voltage experiments here at Texas Tech
taught me that.  Is this safe? Is it redundant?  Usually, it doesn't
seem
to do anything, but about one time in 100, I will see it spark,
because
the cap was charged.  I suppose my NST has enough reactance that it
doesn't always discharge the cap immediately
It is always the first thing I do when I turn the coil off, since an
empty capacitor looks exectly like one charged with a lethal voltage.

Brent
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