Fwd: Construction of an SRSG disc

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Original poster: Terry fritz <tfritz@xxxxxxxxxxxxxxxxxxxxxxx>



Subject: Construction of an SRSG disc
From: Shad <shenderson@xxxxxxxxxxxxxxxx>
To: tfritz@xxxxxxxxxxxxxxxxxxxxxxx
Date: Tue, 08 Nov 2005 09:23:51 -0500


Hi Terry, please forward this to the List and post links to the
pictures.    Thanks!  SH


Hi All,

Here's some pictures and instructions on how to make a small SRSG disc
for a *low powered* coil.  This is ideal for tabletop coils where you
want a lot of performance in a smallish package.  I've used this SRSG on
an OBIT, a 9/30, a 12/30, and a 9/60 NST without fail.  The electrodes
will wear out faster at higher power levels, but they're cheap and
easily replaced.

http://hot-streamer.com/temp/ShadH/

I came across 3 small 1750 RPM motors in a box at the flea market.  Each
was around 2.5-3" in diameter, and pretty much as long as they were
wide.  Each had an armature of ~1.2" or so.  1 was a dud, the other two
worked and were modified with 4 flats for salient pole sync operation.

For a disc, I used double sided 4x6" PC board from Radio Shack.  That
gives me a disc just under 4" in diameter.  The flying electrodes are
8x32 brass machine screws, and the stationary electrodes are 1/4"
threaded brass rod fixed in aluminum heatsinks.  The arbor is from
McMaster Carr, and was pretty cheap.  A block of lexan spaces the disc
out away from the motor some.   I etched 2 rings on the disk (front and
back) for conductivity, so that I can use only 2 stationary electrodes
on the front of the disc.

I fabricated the disc with no more tools than a drillpress, a few drill
bits, a Rotozip tile cutting bit (though I'm sure the spiral saw bit
would work just fine on PCB material), a Sharpie permanent marker to
mask the disc, and a bath of ferric chloride to etch the disc.

I used a finishing nail to mark a center, then used a protractor to lay
out the spacing for the 4 electrodes.  A small drill bit served as an
axle, and a scrap of MDF held everything secure.  The attached pictures
are pretty self explanatory, though I'll be happy to help anybody who
asks.

Shad H.