Fwd: RE: [TCML] Rotory STATIC Gap

[bunnykiller]

Hey Bart...

Even tho the secondary was scavenged for the wire, I went ahead and did 
the NO-NO test on the primary circuit. ( yes I ran the coil without the 
secondary in place)
I ramped the variac up to 80% and hit the button for the relay to 
engage. The first 2 times resulted in the safety gap firing only. The 
3rd and 4th time resulted in an arc going directly to the copper ring 
for about a second or less than the safety gap took over. I had moved 
the rotory electrodes away from the stationary electrodes to make sure 
that they wouldnt be a part of the equasion.  BTW, the safety gap was 
several times louder than what normally occurs with the secondary in 
place....  on very rare and I  mean rare ( happened twice in 9 years) 
the safety gap would fire and then become like a small jacobs ladder arc 
for about a second, the arc would quench and then go back to the popping 
arcs.

Scot D


bartb wrote:

> Hi Scot,
>
> I'll add my 2 cents.
>
> I built a rotary once comprised of small electrodes (3/16"D) 
> protruding out about 1.5". The electrodes were screwed into one side 
> of the disc. The disc was metal. The problem I had is that when the 
> voltage went high enough, the arc would travel down the electrode and 
> across the wheel to the other electrode (or attempt to). This was 
> "drawing the arc" mechanically from one electrode towards the next. 
> When I realized what was occurring, I decided to use an insulated disc 
> (no copper ring) and let the arc pass through the electrode placing my 
> stationary electrodes on each side of the disc rather than on the same 
> side. I think my problem was mainly that quenching was poor. I suspect 
> quenching is also part of your problem here, but not sure.
>
> Are you able to arc the distance if the rotary is not spinning and the 
> rotary electrodes are positioned equal distance away from the 
> stationary electrodes? Giving that a quick test may help determine if 
> you are truly arcing the distance or if your drawing the arc across.
>
> When running, it may quench before it reaches the next electrode in 
> which case may appear like a static gap. I think if this is the case, 
> the next electrode may not fire and then the following electrode has a 
> very high voltage which conducts, this time drawing the arc all the 
> way to the next electrode. And then we start over again. Sort of a 
> very erratic running situation at that point.
>
> Throwing some food for thought out there.
> Take care,
> Bart
>