RE: Spark Gap Problem

To: tesla-at-pupman-dot-com
Subject: RE: Spark Gap Problem
From: Gary Lau 26-Apr-1999 1201 <lau-at-hdecad.ENET.dec-dot-com> (by way of Terry Fritz <twf-at-verinet-dot-com>)
Date: Mon, 26 Apr 1999 20:06:53 -0600
Approved: twf-at-verinet-dot-com

>Original Poster: Adam <psycho-at-tradewind-dot-net>
>
>I just finished my Gary Lau style vacuum cleaner spark gap, and I've got
>a bit of a problem.
>
>Whenever the gap is close, as in Tesla Coil use, the vacuum cleaner
>motor starts to have a heart attack.  As soon as the gap is widened to
>about .25 inch, which is totally unrealistic, everything is fine.
>Suggestions?
>
>Thanks,
>Adam

I'm a little unclear on how a motor has a heart attack.  Does it out
right stop, or runs at an irregular speed?

What do the electrodes look like at the point where they arc?  Are they
blunt and smooth, or are there any unrounded corners or edges?  If there
are any such corners or edges, this will promote premature breakdown and
your gap may power arc - a continuous arc that never quenches and
delivers zero power to the tank circuit.

But then, even if this were the case, I can't imagine how this would
affect the motor operation, unless your power supply transformer is not
current-limited and you are dragging down your AC mains!

BTW, I run my gap at 0.36".  I have no idea what charging voltage this
corresponds to, but your 0.25" doesn't sound unrealistic to me.

Regards, Gary Lau
Waltham, MA USA