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Re:



Hello, Paul

On Mon, 21 Feb 2000 15:41:27 -0700 tesla-request-at-pupman-dot-com writes:
>      Could you folks review my proposed NST protection circuit 
> schematic?
>      
>      Here goes:
>      
>      Coil specs:  
>      
>      10 amp 0-140v variac
>      12KV, 60mA NST, 
>      Tank cap: .01uF Fair Radio cap

This should be about 1.5 to 2X as large

>      Primary: 16 turns .25" Cu tubing
>      Secondary: 6"x24" 22 awg
>      Toroid: 6"x18" (approx) heating duct

That all sounds fine. The secondary can take a lot more power than the
12kV 60mA unit will deliver.

>      
>      Protection/Power circuit (the part i need help with)
>      
>      -20 amp EMI line filter before variac
>      -safety gap after NST, middle grounded to RF ground
>      -2 460pf 30kv doorknob bypass caps, one from each NST leg to RF 
> ground
>      -2 1800 ohm, 113w resistors, one on each leg after bypass caps 
> and 
>      before sparkgap
>      
>      Does that sound okay? Will this setup be okay if I decide to 
> add more 
>      NSTs for 90mA or 120mA?

Maybe use a little less resistance on the power Rs, the caps are fine, as
is everything else.

  The bypass caps seem to be about what 
>      everyone else is using but I'm wondering if the resistor 
> size/rating 
>      is correct. . . 

You could use a lower wattage. Just make sure they can take the voltage.
At best, you'll only be dissipating a few watts in them, if designed
right.

> 
>      thanks,
>      
>      paul mathus


Grayson Dietrich
http://www.electrophile.8m-dot-com