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Re: More Tuning/Debugging



Jim Fosse said (in response to a post from Richard Quick):
<Big Snip of prior posts>

 > With an externally ballasted system, this effect is between    
 > the ballast inductor and the primary capacitance and probably  
 > between the PFC and the ballast also.

 > However, given Richards 1.5 second delay factor, I would look  
 > for an interaction between the PFC caps and the ballast and    
 > variac also. Try removing most of your PFC caps and see if     
 > there is a significant change in the time constant or behavior 
 > of the system. Don't remove all of the PFCs because they       
 > prevent the voltage spikes from the ballast from blowing your  
 > RFI filters and home electronics.

Quoting Bert Hickman <bert.hickman-at-aquila-dot-com>:

> I don't remember your pig-based system using any PFC's, 
> although some of your early writings did suggest their use in 
> conjunction with neons to keep overall current draw down. Based
> upon some of the work that Jim has done, plus your comments 
> regarding lag in responsiveness, it would appear that the use 
> of PFC's could help "neutralize" much of the inductive lag 
> without increasing real power dissipation. PFC's MAY also help
> suppress nasty voltage spikes from getting back into your
> (and your neighbors') mains. 

No, I use a tiny amount of bypass capacitance across the HV
terminal, nothing on the LV side. I am not seeing any voltage
spikes on the mains, though I admit I have not run extensive
monitoring on these lines. My normal observations indicate that
if anything I am seeing a voltage drop accompanied by a large
current surge into the system.

> I'm thinking about adding as much as 250 uF of fused PFC 
> correction to help counteract the inductive reactance of my 
> ballast & pig AND to hopefully keep me from blowing up all the
> other electronic goodies tied to the mains. 

> Any thoughts??

Sounds reasonable. I have an old soda crate packed with old PCB
high-value caps that I have used for power factor correcting
(pfc) caps on my neon banks. Once I get things up and running
again I may give it a try.

Richard Quick


... If all else fails... Throw another megavolt across it!
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