Re: VTTC MOT doubler, is it safe?

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

Original poster: "Jim Mitchell" <Wrenchead-at-starband-dot-net> 

I tried the doubler, much bushier thicker louder arcs, not too much length
increase, I noticed the plate getting a red spot after a short run though, I
am wondering why I only get 5-7" arcs when people talk of 19" and such, my
design is based on the 803 desing from www.chaoticuniverse-dot-com, and I have
the primary tapped at various points which I can change, would anyone happen
to have an 833 for sale?

Regards - Jim Mitchell
----- Original Message -----
From: "Tesla list" <tesla-at-pupman-dot-com>
To: <tesla-at-pupman-dot-com>
Sent: Sunday, November 16, 2003 10:35 PM
Subject: Re: VTTC MOT doubler, is it safe?


 > Original poster: Mike Poulton <mpoulton-at-mtptech-dot-com>
 >
 > Mike Poulton Wrote:
 >  > Original poster: "Jim Mitchell" <Wrenchead-at-starband-dot-net>
 >
 >  > Hi,
 >  > I recently completed my first VTTC, it uses an 813 tube and a MOT from
a
 >  > 1200w microwave.  I am getting about 5-7" sparks from the breakout
point
 >  > during good conditions, and I was wondering would it be at all possible
to
 >  > overdrive this tube and use a doubler on my MOT?  The tube has a max
2200v
 >  > plate, and I am afraid if I put doubled MOT power into it, it will form
a
 >  > fatal arc inside or somthing.  The tube has a graphite plate, so Im not
too
 >  > worried about it melting or anything, but I am afraid of arcs
 >  > inside.  Also, I am not running the tube in optimum conditions, I have
the
 >  > screen and control grid tied together, and the beam plate tied to
ground,
 >  > should I change it so that the screen is tied to B+  by a resistor,
will
 >  > this increase my output noticalbly?  If not, I am going to spend some
big
 >  > bucks on a few 833's
 >
 > Most MOT's seem to produce about 2000-2500V, which is already right at
 > the tupper limit for that tube. Doubling it will give 5-6kV, which is
 > far more than the tube was designed to take. I certainly wouldn't try
 > it. You should be able to max out the MOT's power handling
 > capabilities without voltage doubling. Take a look at the input power.
 > If you have high input power and are only getting 5-7" sparks, then
 > something is wrong.  More likely, it is not drawing much current
 > because the impedance of the coil is too high.  Try better coupling or
 > fewer primary turns.
 >
 > -------------------------------------------------
 > Mike Poulton
 >
 >
 >