RE: Vacuum/blast gap

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

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

If you look at the label on most vacuum cleaners, they typically specify a
10 Amp (or higher) drain.  Though I've never seen one, it's possible that
you have a low power vacuum cleaner, or possibly one rated for a 240V power
supply.  But in my experience, I've always had to throttle down the vacuum
motor with a dimmer or Variac.  There was no performance increase beyond
about 25% full power.

I can't comment on what might be wrong with your gap since you've provided
no details or images of your construction.  It wouldn't be hard to take my
vacuum motor and some lousy electrodes with an inefficient airflow scheme
and make a really crummy gap that makes cool sounds.

The things you want to strive for are:
* The arcing surface of the electrodes should have no sharp edges, corners,
lips, or other features.
* The electrodes should be thick metal so that heat generated is quickly
conducted away from the arcing surface.
* The electrodes should have a shape that encourages the arcing to occur
over as large an area as possible, so that a single hot spot does not develop.
* The airflow MUST be concentrated where the arc is, and secondarily, must
cool the electrodes.

Gary Lau
MA, USA

 -----Original Message-----
From: 	Tesla list [mailto:tesla-at-pupman-dot-com] 
Sent:	Sunday, September 15, 2002 2:47 PM
To:	tesla-at-pupman-dot-com
Subject:	Vacuum/blast gap

Original poster: "Steven Ward by way of Terry Fritz <twftesla-at-qwest-dot-net>"
<srward16-at-hotmail-dot-com>

Hi all,

I recently attempted to reproduce Gary Lau's sucker gap.  I bought the same 
vacuum motor.  My meter claims 3A for the motor, yet Gary claims about 
10A?!?!  Thats not what im getting at.  My problem is that this gaps stinks! 
  Of course, i could have made it differently, but it doesnt perform nearly 
as well as me RQ gap.  Though, i must say, it makes the coolest noises when 
you turn off the coil, and you hear all kinds of pitched wistling from the 
motor.  It sounds real sci-fi, like a major shut down.  Im running with a 
15/120 PSU.  Im wondering it anyone has used this type of gap, but with air 
blowing outward??  So basically, i need some ideas, or reccomendations, on 
what i should do.  Sould i keep the RQ and put the vac motor on it??  Or 
should i make the single gap, but blow out the arc, rather than suck it up?  
All opinions are wanted.  Thanks,

Steve Ward.