Re: The MTSG Metlicka Triggered Gap... (fwd)

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---------- Forwarded message ----------
Date: Mon, 14 May 2007 17:37:53 -0700
From: Jim Lux <jimlux@xxxxxxxxxxxxx>
To: Tesla list <tesla@xxxxxxxxxx>, tesla@xxxxxxxxxx
Subject: Re: The MTSG Metlicka Triggered Gap... (fwd)

At 04:13 PM 5/14/2007, Tesla list wrote:

>By the way, what power levels were you running in that
>photo?
>
>I wonder if there is a "sweet spot" (low enough input
>VA) where the MTSG (as described in the Rosenburg pdf)
>can achieve a first notch quench...or at least one
>sufficient to allow sparks close to what one would get
>using a well designed SRSG?
>
>I suppose for single 12/30 or 12/60 systems, the MTSG
>would probably be a good idea for folks who might not
>have the shop equipment to modify an armature for sync
>use, or to properly balance and drill a rotor.
>
>I have a friend who is considering construction of a
>MTSG, as an upgrade to his static gap.  He is running
>a single 12/60 NST.  I just thought I would ask around
>and get an update, plus I was curious about why that
>design just seemed to fall out of favor.  You and John
>have provided a lot of things to think about.

If I were building a triggered gap today, I'd start with a simple 
approach using a couple pieces of copper pipe with end caps on them 
as the electrodes.  Drill a hole in the center of the endcap for the 
air flow.  pressurize the pipe, so the air flow goes from the center 
of the gap to the outside.  Put a tungsten rod in the center of the 
hole as the trigger electrode and fire it with an auto ignition coil.

I have no idea how much air you might want to blow, but you might 
start by thinking how long it takes the air to move from the center 
of the gap to the outside.  Say you use 3/4" pipe so the distance 
from center to edge is about 1 cm.  You want to quench in, say, 100 
microseconds, so the air has to move 1cm/1E-4 seconds or about 100 
meters/second.  That's fast, but about 1/3 sonic speed, so it should 
be easy to get to.

Your limit is going to be the "choked flow" through the center 
orifice which can't be greater than mach 1 (even a lame 50 psi 
compressor will get choked flow through an 1/8" orifice, for instance).

You could drill a hole in the opposite electrode too, and pressurize 
it, for twice the flow.

The advantage is that your electrodes are copper, which has high heat 
conductivity so you can put heat sinks on them, and you're blowing 
lots of air past the electrode face.


>Cheers,
>
>-Brett
>
>
>
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