RE: Vacuum/blast gap

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

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

Hi,

I think that i will revise my design. My electrodes are only 1/2" couplers 
(brass).  I think that i will go with some thing else. About the motor.  I 
bought the one from American Science & Surplus.  Its a 240vac, but i just 
give it 120.  My meter says a peak at 3A when it starts, then it settles to 
2A.  Gary, im very sorry if i came off like i was putting down your design.  
I didnt mean any harm.  I actually respect a lot of the stuff on your page 
(its in my favorites).  My problem could be that the electrodes are 
different on each side.  One is basically a 1/2" pipe, and the other has a 
adjustable nut that threads on the outside of the pipe.  I will get rid of 
the nut, and find a better way to adjust the gap.  I did notice that with 
only the NSTs and the gap running, the cool looking beam that forms inside 
the gap.  Really cool!  I think that i will just try a slot in the pipe that 
i can adjust the pressure with.  I dont want to mess around with a dimmer 
and i dont have a variac. I will try my vac RQ gap and see if i get anything 
better than 5 feet.  If not, i will give the Sucker another shot.

Steve Ward.


>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: RE: Vacuum/blast gap
>Date: Mon, 16 Sep 2002 08:16:15 -0600
>
>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