Re: First Power Up Test
In a message dated 96-08-01 01:06:30 EDT, you write:
> Well, last night I was able to get enough time to set up and accomplish
>my first test firing of my new coil. It immediately shot out a 20"
>spark from the toroid to my "test ground" which was simply a chunk of
>#14 wire going from my earth ground to a point within 20" of the
>toroid. This spark was very thin and blue, but the multiple arcs from
>the outer primary turn to the strike rail mounted about 1 3/4" above the
>outer primary turn were wide and white--there seemed to be 3-4 firing
>almost at the same time. Apparently my next step will be to get the
>primary and secondary resonant frequencies closer together! My
>secondary with the toroid resonates at 140 Khz so I then picked a tap
>point to give a primary resonance at 130 Khz to compensate for the
>charge build-up on the toroid which I understand typically drrops the
>secondary resonance point. My toroid is 48" in diameter using 6"
>aluminum flexible duct as the outer ring. I had seen up to about 220
>volts going in and 4.5 amps and it was sparking--I stopped watching the
>panel then and just watched the primary arcs!! Any opinions on whether I
>should move my tap to a lower frequency first? Since I am asking a
>question here I'd better list some system specs too:
>Power Supply: 14,400 VAC 10KVA pole pig limited with a Century Arc
>Welder (set a minimum settings for first test)
>Spark Gap: seven gap 1 1/2" dia. copper tube sytem with fan, in series
>with a rotary--12 breaks/rev running slow--maybe 1500-2500 RPM???
>Primary: 14 turns of 1/2" copper with 1/2" gap between turns. About
>11" I.D. and 40" O.D.------Tapped at 9 3/4 turns. Condenser Products
>.025 Mfd cap at 20,000 volts same as many in the group.
>Secondary: 8" dia, acrylic form with 28" of #20 wire using a 48" dia.
>I figure if anyone could suggest going up or down in my primary
>resonance point it might save me some time and possibly reduce the risk
>of lots of generating lots of smoke!! I already have apparently blown
>the free digital volt meter I got! Tonight I hope to try again so any
>comments about your past efforts and knowledge would be appreciated.
Congratulations, it's always great to get those first sparks. Your system
sounds very similar to mine except you have an 8.0" secondary and mine is
6.0". I also had problems with arcs between the top turn of the primary and
the strike rail. I had to raise the strike rail up to about 2.0" clearance
to stop this. I am surprised you only draw 4.5 amps at the lowest setting.
Mine starts out at about 12 amps. Running at this low power, it isn't going
to hurt to be off tune by a turn or two. Just set up the ground wire a few
feet away from the toroid ( I lay a wire or coat hanger on the toroid facing
the ground wire for this) and move the tap around and tune for the best spark
- hot, white and loud. As you go up to full power from here, you will want
to increase the tap outward by 1/4 to 1/2 turn.
I would expect your system to be capable of 8 to 10 foot discharges. The
longest I have got is 80".
Have fun, keep us posted.