[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: [TCML] capacitance and efficiency questions

Hi Kris,
Glad you are looking at Richie's site! The 150 is saying that the LTR size is 1.5 x Cres (or 150%). This is the same as Javatc's Static Gap LTR size which shows 39.8nF (Javatc is has a slightly different factor). If your using a Rotary Gap and specifically a synchronous gap, then you want to go to near 2.5 x Cres which is near 70nF!! As your at 60nF, your cap size is fine. The spark length is based on classical coils and not bipolars, but I expect no significant differences except field control issues. 

When you say your getting 20" arcs, is that 20" per side?
The primary tubing should be fine. As long as it's not getting hot (or even warming up) and there are no obvious arcing problems, then I don't think your quest for longer sparks lies there. Even with a rotary, there are still losses and not all rotary gaps are equal. How's the gap built? 

Bart

Kris Grillo wrote:

I have been reading over Ritchie's site, particularly the section on rotary gap analysis for internally shunted supplies. In the section on choice of primary tank capacitance, the equation is given, Cp = 150xCmatched/BPS. What does the 150 figure represent?

I ran the numbers for my 9000V 90mA NST with a 120BPS sync rotary through this equation. The capacitance came to 33.125nf. This is much different than the figure acquired from JavaTC and from the 2.5xCres suggestion. I assume the larger capacitance suggestion is to load down the transformer and to minimize voltage stress on the cap and transformer. Is there a point where increasing the cap size is counterproductive to arc production?

I have been running my 2" diameter twin coil at 60nf and I am only getting approximately 20" arcs from either side. JavaTC calculates arc length to be a little more than 40". I think someone mentioned that this figure should be 1.4x greater with the bipolar setup, so 56" or 28" per side is what I was expecting. Does this sound right? If so, where is the remainder of the energy being spent? It seems the rotary gap should be more efficient than that. Is 1/8" copper tube not adequate for the primary wiring in this system? Would lowering the Cp value help reduce the inefficiencies?  Is the relatively low 9000V input adding that much to the gap's inefficiencies?

Thanks for your help, guys. I know there are a lot of questions in this message, but I really am starting to understand this stuff better.

~Kris
_______________________________________________ 
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla


_______________________________________________
Tesla mailing list
Tesla@xxxxxxxxxxxxxx
http://www.pupman.com/mailman/listinfo/tesla