Re: V-27 tube coil with staccato pulsing
Hello John and all,
The URL John listed has been updated to:
I too have been doing a little Tube coil work. I wound a 4 x 16 inch
secondary using #28 on a 4 x 20" Acrylic tube. I haven't yet wound my
primary, but it will be a flat primary using #12 pvc insulated wire of
about 20 or so turns close wound, I have yet to figure the best impedance
match. This weekend I setup the new secondary with a old primary on a 6"
pvc tube, and was getting 18" sparks right off (two 833C's), so I think
this secondary will perform well once I get everything else together (and
actually get it in tune). The primary/secondary coupling is to tight with
the 6" primary.
By the way, I used a spray-on Polyurethane to coat the secondary with no
ill effects, been over two weeks.
John, good luck on the project!
At 11:18 AM 12/12/99 , you wrote:
>Original Poster: FutureT-at-aol-dot-com
>Initial testing of the V-27 with the lucite secondary was disappointing.
>Maybe the losses are too high, or maybe certain parameters were not
>optimized. In any case, I installed the old 3" by 12" secondary, and the
>old cylindrical primary, both with polystyrene forms, and the operation
>was somewhat better. I'm getting 24" sparks using the two 833A tubes.
>The wallplug wattage is 2500 watts. The windings get quite warm on
>this small coil at this power level.
>Next I hooked up the staccato control board, along with the thryratron
>control tube, and ran the coil at various pulsed rates. I can vary the
>pulsing from 30 PPS to a much lower rate, and the power input is
>reduced in proportion. Of course the tubes run cool at these slower
>rates. The varying machine-gun-like sound and pulsing is interesting
>to watch. I might re-package this coil into a portable arrangement.
>At the fastest pulse rate, at 1050 watts, I still get a 23" spark output.
>So this coil could easily function on a 15A, 120 Volt circuit.
>Next I'll install the level-shifted power supply, and replace the thryratron
>with an SCR, both for weight and space savings.
>Schematics for some of my other tube coils and staccato circuit, can
>be seen at David Trimmell's website at: