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Help! Suicidal Secondary



Original poster: "Marry Krutsch by way of Terry Fritz <twftesla-at-qwest-dot-net>" <u236-at-earthlink-dot-net>

    Hi everyone.  I'm very new to this, so I have a problem.  I built a
6 inch coil using two of the infamous GE copier xfmrs as a power
supply.  The coil works well (5 ft streamers), BUT....  I have long, hot
sparks running the length of the secondary.  My first secondary for this
coil was 6" by 22" with about 1400 turns.  This burned up, since it was
badly built.  I just wound a new one which is 6.5" by 28" with 1200-1400
turns, and it does the same full secondary arcing.  Coupling doesn't
seem to make a difference.  The coil is tuned to the best of my
ability.  I just put in a better RF ground, and this seems to agravate
the problem.  The only time this arcing does not occur is when the coil
is run in moist air, when there is condensation on the secondary.
Putting a breakout point on the toroid helps, but won't eliminate the
problem.  My toroid is 8" by 22", by the way.  The coil is coated with
large amounts of polyurathane varnish, and holds a static charge after
each run, if that helps.  Also, these sparks run directly on the
secondary's surface.  They punch holes in the varnish with ease.

Here are my specs:
-6.5" approx. diameter by 28" secondary with around 1350 turns of 26awg
wire, wound on thick wall white PVC.
-8" by 22" toroid, whose bottom is 4" above the top of the sec.
windings.
-Primary with an IR of 4", and inter-turn spacing of 1/2" (C-C), tapped
at 8.25 turns
-0.1uF MMC array
-Single static SG with a large 240VAC blower.  Gap set at 1/4".
-2 wirewound 500 ohm resistors as chokes (probably inadequate).
-2 GE copier trannies in series.
-Runs at a freq. of around 100kHz.


This is my first post, so if I did something wrong let me know.
Thanks in advance,
    Winston K.