Re: Herrick's Transformerless Tesla Coil

["Tesla list" <tesla-at-pupman-dot-com>]

Original poster: "K. C. Herrick" <kchdlh-at-juno-dot-com> 

No...if you look carefully at the pair of rotating contact-pairs, you'll
note that one always contacts the outer slip ring while the other, the
inner.  As they rotate, first one and then the other will sweep across
each group of 6 commutating-contacts.  Since the input to the commutator
is to the two slip rings, each side of the input becomes applied to
alternating sides of the outputs, every turn.  The outputs, of course,
are taken from diametrically-opposed pairs of contacts.

As you know, I like the idea of reversal because I'm concerned that a net
direct current passing through the gap will tend, over time, to cause
transferral of gap material from one electrode to the other ("plating",
if you will).  If one always charges the capacitors to the same polarity,
there will, of course, exist that net dc current.

Should the gap fail to fire, the next rotor pass ought merely to
re-charge the capacitors to the opposite polarity--although, for that
pass, to upwards of twice the voltage.  So, gap...take that without
firing!

I note in passing that commutator-contact current is zero at both "make"
and "break", since it's a resonant-charging circuit that fully charges
before the "break".  That should enhance contact (and inter-contact
insulation) life: little sparking.

I also note in passing that I'm going to try a trick to help me lay down
all those little "tiles" onto the stator substrate: I'll try using a
1/32" substrate (later to be glued to a thicker one), first passing that
thin substrate thru my ink-jet printer, which has a straight-thru path,
so as to print guide-lines onto it from my CAD drawing.

[Dave: Do you prefer the leddon-dot-com address, or the LLNL?]

Ken

On Sat, 21 Feb 2004 11:36:37 -0700 "Tesla list" <tesla-at-pupman-dot-com>
writes:
 > Original poster: Dave Leddon <dave-at-leddon-dot-com>
 >
 > Hi Ken,
 >
 > I noticed that in your latest drawing your slip rings are now
 > continuos.  Does this mean that you've abandoned the idea of
 > reversing the
 > polarity of the charging voltage every 180 degrees of rotation?  I
 > never
 > completely understood the rational for this reversal and I can see
 > where
 > doing away with this requirement certainly simplifies the design
 > while also
 > resolving the question of what happens to the energy in the caps
 > should the
 > discharge gap fail to arc.
 >
 > Dave
 > Pleasanton, CA
 >
 > At 06:30 PM 2/20/04 -0700, you wrote:
 > >Original poster: "K. C. Herrick" <kchdlh-at-juno-dot-com>
 > >I've worked up a dwg of the prospective commutator assembly for
 > >http://hot-streamer-dot-com/temp/tspk17s1.pdf.  See
 > >http://hot-streamer-dot-com/temp/tspk17a1.pdf.
 > >
 > >Notice that the commutation configuration is a bit different from
 > the
 > >schematic.  Also that I show a tungsten rod for the gap element.
 > >
 > >KCH
 >
 >
 >
 >