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From: gnome@olivee.UUCP
Newsgroups: net.analog
Subject: Re: Re: Jacob's Ladder
Message-ID: <385@olivee.UUCP>
Date: Mon, 10-Jun-85 18:14:42 EDT
Article-I.D.: olivee.385
Posted: Mon Jun 10 18:14:42 1985
Date-Received: Fri, 14-Jun-85 00:58:01 EDT
References: <72@biomed.UUCP> <344@moncol.UUCP> <11218@brl-tgr.ARPA>
Organization: Olivetti ATC; Cupertino, Ca
Lines: 37

> Well I've got a surplus 0-60KV power supply in my living room,  I'll
> have to give it a try.
> 
> -Ron

WARNING!!  DANGER WILL ROBINSON !!!

I would like to add this little tidbit to the Jacob's ladder
discussion --  STAY CLEAR OF HIGH VOLTAGE DC SUPPLIES ! ! ! !

All of the discussions about neat arc generating devices has
been fine - but it should be made clear that HVDC supplies are
very different animals.  Unlike 60Hz AC arcs produced by neon
sign transformers, HVDC arcs from surplus laser/xray power
supplies are loud, unpredictable, and sometimes fatal.

Most (big) HVDC supplies arc over in the following manner -
 1) Upon power-up, nothing happens for a few seconds (uh-oh)
 2) as the supply charges its internal capacitors, a slight
    crackling sound might be heard around the outputs of the
    supply.
 3) The arc (to be) usually looks for the least-plausible
    path to ground and jumps with an incredibly load BANG!

 4) The power supply starts charging again and looking for a
    new place to arc to (the old spot isn't there anymore).

At BTL, we had a display terminal that ran with a 10KV DC
tube (CRT) supply.  One time, the HVDC jumped to a deflection
board and literally vaporized a TO-220 transistor; the plastic
case and one of the three leads became a little black crater.

Low frequency HVAC can be fun and (reasonably) safe.
HVDC can easily blow you away and stop your heart.  As
they say on the Hitchhiker's Guide - "Whole lots of No-Fun!".

Gary