RSG Construction

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

Original poster: "Steve & Jackie Young by way of Terry Fritz <twftesla-at-uswest-dot-net>" <youngs-at-konnections-dot-com>

I have been building a RSG lately, and thought I would share some thoughts
about it:

Rotor material.  I know G-10 (Garolite) is preferred by many as the best
choice.  But I decided to instead use GP03 which is Electrical Grade
Fiberglass.  I ordered 12 x 12 x 3/8 inch sheets from Mc Master-Carr for
$9.73 each.  This is about a fourth as expensive as the G-10.

It seems to be an ideal material.  Temp range is up to 400 degrees F (higher
than the 284 of G-10).  It has good tensile strength, very dense and heavy,
and is an interesting light pink color.  But what I especially like is that
it can be machined with ordinary tools suitable for metals.  I used a
regular metal cutting blade in a saber saw to roughly cut a disk - no
problem.  I did it outside with the exhaust of a vacuum cleaner aimed to
blow away the fine power produced to avoid breathing it or getting it in my
eyes.  Ordinary drills work fine with it.  In fact, out of desparation I
used a wood bore to drill the 7/8 inch center hole, and the bit survived.
The powder produced from machining is a mess to clean up but it doesn't seem
to cause skin itchness or other problems.

I am using an angle grinder to spin the rotor for a DC asynchronous RSG.  To
true the rotor, I just mounted a small grinding wheel (1 inch diameter
cylinderical type as used with air tools) in a bench drill press.  I clamped
the angle grinder, mounted on its wood base, on the drill press table so
that the disk lightly pressed against the grinding cylinder at the smallest
disk diameter point, held the disk to keep it from spinning, then turned on
the drill press.  I slowly rotated the disk, and ground my way around the
disk circumference.  Viola - a very smooth, true, well balanced disk
resulted with little effort and no fancy lathes, etc.  GP03 grinds very
nicely.  I believe one should do the final disk machining with it mounted in
its final arbor so that arbor and motor shaft imperfections are taken care
of when the outside edge of the disk is trimmed.

Bottom line - I like GP03 a lot, and I recommend those building RSGs give it
a try.  The stationary gaps have aluminum power transistor heat sinks to
dissapate heat.  Someday I will report how the RSG works.  It's a bit
unusual as it will function as a SPST switch - charging the tank MMC in one
position, and discharging it through the primary in the other position.
This scheme is to avoid the need for a charging resistor or choke as the
tank circuit will be completely isolated from the power supply when its gap
fires.

--Steve