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Re: New coil woes protection circuit



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 > > >