Re: Poulsen first light

["Michael H Nolley" <nolleym-at-willamette.edu> (by way of Terry Fritz <twftesla-at-uswest-dot-net>)]

> Original poster: "Ed Phillips" <evp-at-pacbell-dot-net>
>
> Those of you who might be interested in an arc-driven TC should take a
> look at this:
>
>         http://www.angelfire-dot-com/nc2/whitetho/1908poul.htm
>
> Figure 3 shows the discharge at the top of what looks like a CW Tesla
> Coil!  Date is June, 1908.  The discharge looks rather puny for a device
> which had 1 kw input (to the arc, perhaps 400 watts to the coil if it
> was getting all of the power), but perhaps the resonant coil wasn't
> getting all of the power.  The actual power is quite vague, as you will
> see if you read the text.  Anyhow, pretty interesting for so long ago,
> and perhaps the photograph doesn't do credit to the actual discharge.

    I saw this too and was intrigued.  For all who are interested in an
update, I was able to get the gap to fire by reducing the number of turns on
the chokes to 2000 apiece instead of 4000.  I just wired the two secondaries
in parallel.  However, I still cannot get the gap to fire without the
auxilliary 10k resistor.  When the resistance is removed, the arc "thumps"
and the blow-out cores visibly jump.  You can actually see the arc being
blown out into a loop and extinguished.  I'm thinking one of two things:
either I need to further reduce the number of turns in the chokes to operate
at higher currents, or reduce the supply voltage, or both.  Or, conversely,
I could just raise the voltage.  Contrary to what seems to be commonly
thought about arc converters, it seems reasonable that I could operate it at
4 or even 6kv, just as long as the current was kept down.
     Ed:  to explain the picture, I think arc converters can be quite
inefficient.  Also, one would assume that the coil was driving a large
antenna, which would suppress discharge.  Even so, with my current setup and
the limitation of the 10k resistor, I'm getting a very enthusiastic five
inch arc off of the secondary--what one would expect from a very souped up
flyback generator.