RE: Tesla Coil Electrical Fields - was Dangers of running 2 coils...


I looked at the pictures and the coils were about 14' apart.  I was running
about 2kva at that time if I remember correctly (we made many changes that
evening) and was having some trouble getting breakout with the topload
configuration at the time. Don't know if it makes any difference but we were
both sharing a common ground wire (Ground rod with a 10' lead to my coil
then 10' more to Ross's coil).

We did run the coils at the same time and had a blast...  I took some
pictures but between messing with coils, worrying about safety, and setting
up the other camera, I didn't notice the aperture setting got bumped and
ended up with so-so pictures when they were running together.  I'll try and
post them to my Web site this week.

Brian D. Basura

-----Original Message-----
From: Tesla List [mailto:tesla-at-pupman-dot-com]
Sent: Saturday, February 27, 1999 10:29 PM
To: tesla-at-pupman-dot-com
Subject: Re: Tesla Coil Electrical Fields - was Dangers of running 2

Original Poster: "John H. Couture" <COUTUREJH-at-worldnet.att-dot-net> 

  Russ -

  With reference to my post on electrical fields near a Tesla coil do you
think the Faraday magnetic field from Brian's coil could be inducing
currents in your coil and charging your capacitor? Your coil and Brian's
would be a good test for the presence of this field. Radio engineers would
say that it was the electromagnetic field that induced the charge. But is
this correct? According to Terman the Faraday induction field near the
antenna is stronger than the electromagnetic field but would drop off much

  The only way to properly test for the Faraday magnetic field would be with
a gauss meter that could detect an RF frequency magnetic field and also be
shielded from the electromagnetic field. I have not heard of anyone who has
ever done this.

  What input power was used?  I would be interested in more details on the
setup, like what was the closest your primary coil came to Brian's? Part of
Faraday's discovery was that a changing current in one wire could produce a
changing current in an adjacent parallel wire.

  John Couture


At 06:33 AM 2/26/99 -0700, you wrote:
>Original Poster: "Ross W. Overstreet" <ross-o-at-mindspring-dot-com> 
>Last weekend I lugged my coil over to fellow coiler Brian Basura's
>house.  After the initial ooohs and aaahs, we took a break to so some
>tuning to our respective coils.  Brian finished while I was still
>working on opening my gap up a bit and asked me if he could try some
>quick test runs.  I was about 2X as far away as I figured that his coil
>could reach, so I said go for it.  About 15 seconds into his run I
>wondered if my cap might possibly be getting charged from the huge field
>that his coil was emitting.  I took the "red" cap wire that was in my
>hand and brought it close the the "black" cap wire on the gap.  At about
>1/4" away I got a huge "bang".  I quickly slid the wires on the same
>bolt and backed away!
>This brought my attention to several issues
>1.  The caps should always have a shorting wire when you are working on
>the coil.  I always discharge them with a "shorting tool", but I now
>realize that this practice is inadequate.
>2.  Similar coils can act as a transmitter / receiver pair!  Be careful
>messing with one while the other is running close by!
>Later in the night, we observed that I could make the spark gap fire on
>his unplugged coil while mine was running.  Our coils were about 10 ft
>It almost got me - don't let it get you!
>Ross Overstreet
>ICQ# 20762411