Re: Help! Suicidal Secondary

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

Original poster: "rheidlebaugh by way of Terry Fritz <twftesla-at-qwest-dot-net>" <rheidlebaugh-at-zialink-dot-com>

Computer programs don't cure problems they only analyze them.Ihave some
ideas what could be the cause, but lets see if we con stop the results.The
number of turns and the length causes a high volts/inch ratio. so a change
in secondary shape should arrest the problem. Cut some plastic washers 6.75
in ID  x 9 in OD and put them arround your secondary about 3 in appart and
bond them with epoxi or fiber-glass resin with no cracks to the secondary
starting from the top down about 1/3 of the coil length. This should move
the arcs away from your coil windings and stop the racing arcs. Slightly
larger wire or spaced windings will reduce the volts/inch ratio to a better
level in the future. I use spaced windings my self so I get high voltage and
close coupeling for more current. I often nead rings on my secondary.
   Robert  H  

> From: "Tesla list" <tesla-at-pupman-dot-com>
> Date: Sun, 06 Jan 2002 12:04:47 -0700
> To: tesla-at-pupman-dot-com
> Subject: Help! Suicidal Secondary
> Resent-From: tesla-at-pupman-dot-com
> Resent-Date: Sun, 6 Jan 2002 12:47:23 -0700
> 
> 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.
> 
> 
>