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Lead acid powered solid state TC/Exploding Fruit
> Kevin,
> It must be basicaly capacitive discharge.Otherwise,if
> arc really puncturates the glass of your plasma globe
> you may say goodbye to it.There was thread "Conducting
> through glaass" on the list month or two ago.I posted
> the question how much energy can be transmitted via
> arc
> glass bulb -hit object that way.Nobody responded.
> THe out of tune condition may also be significant in
> as how do you fell the arc.
> Boris
I've seen this myself. I've got a small commercial plasma globe lying around
somewhere, and I remember a silly experiment, where I balanced a small
orange on top of the globe while it was running. There was a continuous
streamer running to the glass just below the orange. Anyway, the orange
built up a charge sufficient to cause small discharges to grounded objects.
I 'spark eroded' a pattern into its surface by holding a metal nail file
about 0.5mm away from the surface of the fruit. This continued until the
smell made me unpopular and I was forced to stop. :)
I'd guess that the arcs would have been no longer than 0.5mm, so I'd guess
maybe 1.5kV, but at tiny current because I couldn't feel any shocks
(although I could if I touched the orange directly). There was *some* power,
because it was enough to blacken and erode the orange peel. As for
conduction vs. capacitive effects, either could be plausible, but I'd
personally go for capacitive.
Anyone tried balancing fruit on top of a TC? Inquring, though perhaps insane
minds want to know what happens. :)
On another note, has anyone built a solid state TC driven from lead acid
batteries? I'm keen on taking the plunge and building a coil, but can't
really countenance using mains power here.
The rationale behind this is because we are a long way from the nearest
town, so our power is fed via a (long) 15kv line ending at a pole pig next
to the house. At the best of times our power is flaky - I've lost a TV set,
five washing machines, a microwave oven, a deep fat fryer, several PC
motherboards and power supplies and the power supply of a rather exotic
music synthesizer so far, all within the last year and a half. doG only
knows what would happen if I tried to run a TC - all that was just caused by
plugging the equipment into the mains. Also, we have a dozen or so PCs here
and a permanent internet connection which all runs 24/7, as well as an audio
studio with maybe 1km of cable in interconnects, so the usual 'unplug and
disconnect' thing isn't really feasible. We now have a couple of big UPSes
driving the computer and audio equipment and haven't had a major failure
since they went live, but I don't trust them to soak up the kind of abuse
that a TC can deliver - I'm worried that as we're on the end of a long 15kv
spur that we are seeing some kind of (relatively) high impedance
transmission line effects. Is there any way of decoupling the HV side of a
pole pig, in the sense that you decouple the supply as a matter of course
close to VLSI chips to clean up their power rails?
I figured that a bunch of lead acid batteries in series could generate a
very nice rail voltage of maybe 100 - 200V at potentially hundreds of amps.
This would provide a good, very well behaved essentially ripple free low
impedance supply for a hefty MOSFET or IGBT H-bridge inverter, whilst
removing the need for the TC to have any kind of coupling with the mains.
Sure, you probably couldn't run the coil for very long periods, but
certainly long enough to have fun. The portability is a big plus, of course,
in that I could take it a long way from the nearest building and simply
drive a spike into the ground to make an RF ground.
Sarah