Re: Variac vs. Fan speed control

Subject:      Re: Variac vs. Fan speed control
       Date:  Thu, 24 Apr 1997 18:48:37 -0700
       From:  Open Minded <bturner-at-apc-dot-net>
Organization: I'm NOT organized!
         To:  Tesla List <tesla-at-pupman-dot-com>

Tesla List wrote:
> Subject:   Re: Variac vs. Fan speed control
>   Date:    Thu, 24 Apr 1997 15:22:11 +0500
>   From:    "Alfred A. Skrocki" <alfred.skrocki-at-cybernetworking-dot-com>
>     To:    Tesla List <tesla-at-pupman-dot-com>

> Hay Chip, ever hear of a Faraday shield? Seriously, Chip I currently
> use phase shift light dimmers to control my rotory spark gaps {I use
> universal motors} and I have no problems BUT I totaly enclose the
> dimmers in a grounded metal box. Apparently what happened in your
> case is the triac was picking up some of the radiated R.F and being
> driven into continous conduction, try it again but this time enclose
> the control in a grounded metal enclosure.

Reminds me of an interesting event that occurred during one of my
Tesla coil performances w/Bill Wysock some years ago. We were doing
the ol' arc & spark show, and to get maximum effect, we had the
guy on the lighting (NOT lightning, we did that part...) board
drop the stage lights. When we lit up the coil, the stage lights
came right back on! Obviously the power leads to the lamp heads
were picking up the RF, which was enough to trigger the triac's
in the dimmer head. Needless to say, we became persona non-grata
with THAT lighting guy...oh well. No harm was done to the board
or the lights, as we made DAMN sure everything was properly

Although, there was ONE time where the lighting guy DIDN'T follow
our instructions to shut down, and UNPLUG the control cable from
the dimmer board to the power controller. In that case, we did
manage to fry the front end of the power unit, but again, fortune
smiled, as it was a rental unit, with the rental people commenting
that it was no big deal, as that particular system was prone to
failing under NORMAL situations. That was the only (and we plan to
KEEP it that way) time we have ever run into problems, and I've
been doing this for over 8 years now...

- Brent (who demonstrates wireless lighting big-time!)