Notes-Questions-Article-All

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

Original poster: "B2 by way of Terry Fritz <twftesla-at-qwest-dot-net>" <bensonbd-at-erols-dot-com>

Hi All
    I have a few questions and observations that aren't enough for separate
posts:

Terry:  Nice pictures of your trigger setup!  Have you tried biasing your
midring with something like 200 MOhm resistors?  A gap between the coil
output and midring will sharpen the risetime and enhance triggering (scope,
pictures??:).

Marc:  A capacitor made with round plastic disks and metal foil rings would
have an incredibly low inductance if one side was connected to the center
and the enclosing "can" became the other side.  The polycarbonate disks are
a little lossy but very convenient.

Dr.Rzeszotarski:  Nice measurements!  Your measurements appear to be for
nonuniform field gaps.  Smooth electrodes to give a uniform field will
allow the electrodes to be moved closer together.  This will reduce some
losses.  A large brass or tungsten midplane with a center hole (diameter of
hole = gap spacing, edges tapered to a rounded point) will make it possible
for multistreamering to take place when triggered with a HV source with a
risetime greater than 10 ns.  This risetime may be achieved with a uniform
field gap ("Chinese" brass doorknobs with semiRogowski profile) between the
HV (Ig. coil) and the midplane.  Pressure will increase the risetime.  The
multistreamering with concomitant multichanneling will decrease the average
resistance of the spark gap.  Schedule 80 PVC pipe will take at least 2
atmospheres (30 PSIG) of pressure.  This will allow the electrode gap to be
halved for the same voltage.  This will reduce losses even further.

Elli:  Nice idea!  If everyone on the list gave just one dollar, that would
pay for the blown hard drive and connection costs.  Mine is in the mail!

Ignition coil power source:  Since ignition coils can be connected in
parallel and light dimmers can be had in high wattages this may eventually
replace the neon as transformer of choice.  Junkyards have more ignition
coils than neons.  HEI ignition coils (square shaped with a HV nipple) are
designed for a several hundred volt input pulse.  More power may be had by
using a 110 to 220 stepup transformer and a 220 V lamp dimmer.  The coil
frames will need to be mounted on heatsinks.

    I have put up to 400 watts through a pair of antiparallel connected HEI
Ig coils for up to 5 minutes before they got too hot to touch.  The 4 inch
dark orange flaming arc put a France 15-60 to shame.  200 watts per coil
should be doable in oil or with forced air on a big heat sink.  Scalability
and weight are definite pluses.

Motor as ballast:  Why not lock the motor shaft so that it cannot rotate.
The rotor can be slid in and (one bearing will have to be extended) out of
the center of the motor coils in a similar fashion to the core of a neon
bombarder.  The current will have to be limited or the windings will get
too hot and melt.  Connecting the windings in parallel so that the field
doesn't rotate would help.

Toroid Design:  Has anyone tried joing the ends of flex duct with a
pressure tight seal.  If it could be done then the flexduct toroid could be
slightly pressurized.  This would add more rigidity and immunity from small
bumps.  If a seal is not possible then maybe a balloon or an innertube?

Contrawound Toroidal Helix Antenna:  IEEE Transactions on Antennas and
Propagation, Volume 49, Number 8, August 2001.  Nice article describing one
of Dr. James F. Corum's patents.  An interesting concept that might have
applicability to future primary design???  (Especially for those interested
in multiphase primaries:)

Cheers,

B2