Re: [TCML] rotary gap disk

[bartb <bartb@xxxxxxxxxxxxxxxx>]

Hi Phillip,

One thing I didn't point out is that dwell time affects are psu and cap 
dependent. Same problems can happen in large discs also. But more likely 
in smaller disc sizes given the typical psu and cap sizes used. I have 
no clue what psu, cap size, or disc size you used, so my comments are 
more of a condition that is possible. Worst case is a small psu current, 
small disc, and relatively large cap. I'm not sure if you were in this 
territory, but thought I would throw it out there as food for thought 
(though you may already realize this aspect).

Bart


bartb wrote:
> What can happen in a small rotary is that the electrode mechanical 
> dwell time can become excessive, up to the point of the cap charging 
> and discharging a time or two during the mechanical dwell. This can 
> cause a problem with steady firing voltages and so it tends toward a 
> chaotic voltage at each break. Actually, in this situation, it helps 
> to have a bit larger gap to prevent these occurrences. But as the disc 
> is larger in diameter, the dwell time reduces linearly. A 10" 
> rotational diameter would have 1/2 the dwell time as a 5" rotational 
> diameter. As the diameter of the disc is increased, it doesn't take 
> long before a tight gap is ideal (as tight as is mechanically sound). 
> It's simply another cool aspect to larger rotational diameters. Of 
> course, the stresses on the disc increase with larger diameters, and 
> another good reason to use G10 or G11 as an insulated disc (at least 
> for hobby coils).
>
> Regards,
> Bart  
_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla