Re: good results and sync gapsl

From: 	Peter Electric[SMTP:elekessy-at-macquarie.matra-dot-com.au]
Reply To: 	elekessy-at-macquarie.matra-dot-com.au
Sent: 	Wednesday, August 06, 1997 4:13 AM
To: 	Tesla List
Subject: 	Re: good results and sync gapsl

>         Sounds like I am in for trouble with my cap. I have successfully run
> it at 15KV now, but I am only game to run it for about 5 seconds at a
> time. There is only 15MM between the flashing and edge of the poly.
> When I was building it I thought that oil would sort out the problem as
> I have made another dry fired cap with only about 20MM to the edges and
> have had no problems even at 15Kv. It was made from 4MM perspex though
> ( and not rolled) :)
> What is the difference in losses between polyethylene and perspex does
> anyone know ? If my cap does blow I think that I will just go back to
> flat stacked perspex plates.
> Also I did try a muffin fan and found at  low powers levels it made the
> sparks longer and fatter, but when I started to raise the power level
> the fan seemed less effective.
> Cheers
> Jason

The general consensus seems to be that perspex is fairly lossy at RF
frequencies although not as bad as glass which I believe has already
been succesfully used by some coilers on this list. If it seems to work
OK, you might as well go on using it!

I have also noted that the sparkgap quenching needs greater airflow at
higher freqs. I am presently using two squirel cage fans (out of a
microwave oven) one blowing and one sucking air through the gap and this
works well at 15kV 60Ma but I intend to try a rotary sync gap as soon as
I find a decent sync motor.

I have a DC sync motor from a large hard disk drive. Has anyone on the
list successfully used one of these in a rotary gap?


Peter E.