Re: Gap Firing Characteristics (was Re: Tesla Coil Blunderbusses)

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

Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>" <FutureT-at-aol-dot-com>

In a message dated 4/10/01 8:48:15 PM Eastern Daylight Time, tesla-at-pupman-dot-com 
writes:

> After 
>  being inspired by a piece from Scott Myers on how he improved the 
>  output of his coil, I eventually got around to building a larger 
>  oblate topload for the coil. Secondary Fr went from about 155kHz to 
>  130kHz, a figure which serendipitously allowed me to add a single 
>  turn to the primary to maintain tune, boosting primary inductance by 
>  about 50%. (Aside - the primary ringdown showed an enormous reduction 
>  in losses). 
>        Up until the mod was done, the gap work smoothly with no 
>  airblast. Following the mod and with the gap in no way altered, 
>  operation was totally erratic. Much messing around failed to get it 
>  running smoothly. At that point, I started running a jet of air 
>  through the gap and through much adjusting of the airflow and gap, 
>  got closer to good operation but still very erratic. It would fire in 
>  bursts of half a second to a couple of seconds and then just stop. 

Malcolm,

Yes, I can see how (as you suggested [or partly suggested],
in your other posting), if the large toroid delayed the breakout, 
or even prevented it at times, this would delay the quench, and 
also affect the cap charging, and may have prevented the gap 
from firing at times. I have found in my work that larger toroids 
hurt the quenching, (but increased the spark length nevertheless).

I wonder if the coil would have benefited from a sync rotary gap,
or even a triggered gap.

John Freau