Re: RSG material?

["Antonio Carlos M. de Queiroz" <acmq-at-compuland-dot-com.br> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

Tesla list wrote:
> 
> Original poster: "Travis Tabbal" <bigboss-at-xmission-dot-com>

> I've also seen static gaps used in series with the RSG.. what's the
> point? ;) Seems like the motion of the flying electrode would quench
> the gap reasonably quickly. I get the feeling I'm missing a crucial
> detail here.....

The motion of the electrodes is far too slow to quench the arc, that
see an usual RSG rotating at 60 Hz as a -static- gap. The main purpose 
of the RSG is just to time the instants where the gap fires, and so 
it makes sense to add more gaps in series with it to improve quenching
and reduce power dissipation at the RSG.
A quick calculation:
A coil resonating at 200 kHz, transferring energy in 5 cycles (k=0.105), 
produces the first energy mimimum in the primary ("first notch")
in 25 us.
A RSG rotating at 60 turns/second rotates 360 degrees in 1/60 seconds,
or one degree in 1/(60*360)=46 us.
In the total time of the energy transfer the gap turns about 0.5 degree
only. 
A RSG that moves the electrodes 1" in this time would have a
circunference of 2*360", or a diameter of 2*360/pi=229", or 58 cm.
Rather big, compared to the rotary gaps that I have seen.

Comments?

Antonio Carlos M. de Queiroz