Re: New coil woes protection circuit

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: JBarrett@xxxxxxxxxxxxxxxx 

The protection circuit consists of a very thick piece of plastic cut into a 
U shape. In the vertical portions of the U a 1" piece of solid brass stock 
is mounted and will slide in and out for adjustment. In the horizontal 
portion of the U is mounted a piece of copper that extends upwards and 
between the brass stock. The copper is hooked to ground.

I was adjusting the brass stock in and out from the copper until it only 
fired occasionally but my nst's died only after a couple of attempts. I 
never put more than 70% power to the coil.

I think the problem is due to the fact I grounded the copper to the same 
ground as the nst and not the ground rods. I downloaded a schematic that 
showed it this way but I'm wondering if this was the way to go.
Thanks
Jim
-----"Tesla list" <tesla@xxxxxxxxxx> wrote: -----

To: tesla@xxxxxxxxxx
From: "Tesla list" <tesla@xxxxxxxxxx>
Date: 05/08/2005 05:18PM
Subject: Re: New coil woes

Original poster: "Dr. Resonance"



Describe the protection circuit you are using between your NST and the
oscillator tank circuit.  Are you using anything?

Dr. Resonance


>
> Hello again,
>
> I was attempting to fire up my new 4" coil with a 12,000 volt 30 ma nst.
> The spark gaps started firing hard and fast with just an occasional spark
> at the safety gap. Flourescent bulb blinking in my hand and then poof!.
The
> gaps slowed way down and no more safety gap action.
>
> One dead nst. So I go to my backup nst. 12,000 volts 60 ma. Same exact
result.
> Same side too!
>
> What am I doing wrong here? very discouraged! The safety gap is two pieces
> of brass stock with a piece of copper pipe between them that is grounded.
I
> can slide the brass in and out toward the pipe for adjustment.
> Coil specs
> Specs:
> 21" of 22 guage wire on a 4" PVC pipe
> 12,000 volt 30 ma Neon Sign Transformer
> 9 pieces of 1" thick wall copper pipes 6" long for spark gap
> small fan to cool gap 9 pipes 8 gaps spaced very close but not touching
> Small Aluminum Toroid probably 8" across and 3 to 4 inches minor diameter
> Safety gap
> I tried two separate caps 1 is a Universal Voltronics 28 kvdc 0.01 uf oil
> filled
> the other is a GE 0.01 25 kvdc 700 disch/sec
> I'm also using a variac to control the Neon Sign Transformer
> Two 8 foot ground rods
> Primary Flat confiquration 1/4" copper tubing at 1/4 to 3/8" spacing
> Thanks
> Jim
>
>
>