RE: Garage door opener protection

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

Original poster: "Lau, Gary by way of Terry Fritz <twftesla-at-qwest-dot-net>" <Gary.Lau-at-compaq-dot-com>

Unplugging just the power cord is not enough.  Most door openers also
have low voltage wiring going to remote pushbuttons and safety sensors.
These inputs are surely more sensitive to HV transients than the AC
mains wiring, and need to be disconnected as well.  Don't forget, the
opener's chassis is effectively tied to ground by virtue of the metal
frame, and any wire extending from the box is a capacitively-coupled
antenna to your streamers.  

Install a 3 (or whatever) position connector on your control wires as
close as possible to the opener (couple inches max) to make it easy to
connect and disconnect it.  I also tuck the short wire antenna back into
its hole in the chassis.  Using this precaution (and no Faraday cage),
my coil regularly connects to the opener's steel track with no ill
effects.  See http://people.ne.mediaone-dot-net/lau/tesla/sparks.htm

Gary Lau
MA, USA

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Sunday, June 10, 2001 11:19 PM
To: tesla-at-pupman-dot-com
Subject: Garage door opener protection


Original poster: "Steve White by way of Terry Fritz
<twftesla-at-qwest-dot-net>" <slwhite-at-zeus.ia-dot-net>

I am in the process of buiding a pole transformer powered coil
theoretically
capable of 8 foot arcs. I would like to run this coil at perhaps partial
power
in my garage at times. Like many people, I have a garage door opener. Is
there
any advice on how to protect the opener from damage? The only idea that
I have
is to build a grounded Faraday cage around it and unplug its power cord.
The
Faraday cage will take care of the electric field but what about the
magnetic
field?