Re: Covered primary

["D&M's High Voltage" <dmshv.davmckin-at-gte-dot-net> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Jim, List:

I've used either 3/16" or 1/4" thick plexiglass for 10 years
now on all my coils.  I've actually never had the arc go right
through the plastic - even on the big coils.  What happens
when the arc hits the plastic is they just spread out in a circle
- really neat looking effect.  The only reason I've came up
with so far (just a theory though) is the arcs don't have
enough power (it's lost in the arc itself) to punch through
the plastic.  As Jim mentions, it will go right through if you
hold a ground rod up to the plastic though.  Don't use
a cover with a strike rail for this reason.  An analogy I use
is it's like the plasma globes.  The arcs go all over until you
put your finger up the  ball, causing the arcs "to go
through" the glass.  Also, the covers I've been using rest
about 1/2" above the copper tubing itself (never directly
on it).

David L. McKinnon
D&M's High Voltage


> Original poster: "Jim Lux" <jimlux-at-jpl.nasa.gov>
>
> At the voltage of the secondary (several hundred kV), you're going to need
a
> pretty thick piece of plastic to stop it and not just get "punched
> through"..
>
> it wouldn't affect the coupling though... Magnetically, the plastic isn't
> there...