Re: CD 942 failure tonight

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

Original poster: "John Richardson" <jprich-at-up-dot-net> 

Hi Gerry,


If the shunts were altered, or like you say are
 > saturating, I would think this could have the affect of raising the Cres
of
 > the transformer.

The transformer has never been apart.  As a matter of fact, it is brand new,
removed from it's original box


 > I don't remember if John indicated 50 or 60Hz line.  I've been assuming
60Hz
 > in the calculations (John, maybe you can verify this).  If he does have
 > 50Hz, then the Cp needs to be raised to 100nf.
 >
 > Does seem like the Cp needs to be close to the primary and SRSG because of
 > the high current paths.
 >
 > Gerry R

I am on 60hz.  (Live in Upper Michigan.)  I am going to give it one more go
tonight with the same 9 by 4 setup.  I received my 100uf and 25uf run caps,
and am going to lash up a cap value that should work with John's phase
controller.  Should allow me some fine tuning on the SRSG, although I really
believe it is almost dead on.  I replaced the wiring from my control center
with #6 stranded copper sheathed in vinyl tubing.  Each lead is exactly
eleven feet long.  Unfortunately, I cannot alter the location of the gap or
cap, as it is all integrated onto a roll around control center.  My
reasoning at the time was to allow this pri/sec setup to be used with
different trans, caps, gaps, etc.  The NST safety gap was set to just not
fire with just the NST.  This width came close to, if not slightly over, .5
inches.  I set the rotary electrodes DANGEROUSLY close.  (Don't do this with
a propellor gap unless it is enclosed!) I ran with the new heavy cables, and
the cables are now cool, but the primary is HOT.  Hot enough to melt the
vinyl tubing that insulates a big alligator clip that allows pri.
adjustment.  And another cap is getting black from the inside out.  Lots of
bad words going around in the basement!

Thanks for your interest and comments,

John Richardson
 >
 >  > Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>
 >  >
 >  > Hi John and All,
 >  >
 >  > I looks at John's video and caps:
 >  >
 >  > http://hot-streamer-dot-com/temp/P3070026.jpg
 >  >
 >  > There is just a big hole in both about 3/16 inch deep.  It looks like
it
 >  > just exploded...  There is not enough energy in a single cap to do that
so
 >  > I don't know where all the energy came from.  There was no other arcing
 >  > inside.  It just looks like it got a single high energy over voltage
that
 >  > blew a big hole in the cap.  Apparently John does not have the strings
 >  > cross connected or anything like that.
 >  >
 >  > I think he should set his safety gaps like this:
 >  >
 >  > http://www.pupman-dot-com/listarchives/2000/January/msg00044.html
 >  >
 >  > The resistors were very well attached, far from the cap, and checked
out
 >  > fine.  So I don't see any obvious cause.
 >  >
 >  > There is a small chance the big 12/120 NST Transco is saturating the
 > shunts
 >  > and maybe putting out too much voltage/current but I have never seen
that
 >  > before with a LTR rotary.
 >  >
 >  > One thing that does worry me.  He has his primary far away from the
cap,
 >  > NST and all.  They are hooked up with about 6 feet of wiring.  I wonder
if
 >  > that long primary wire's inductance is doing something odd and causing
 > high
 >  > voltages back on the caps or something?  I am not sure if that would do
 >  > something bad or not.
 >  >
 >  > So I don't know what is going on really :-(  but something sure is
 >  > strange.  He says the primary gets hot and the cap are heating some.
I'll
 >  > grind the cap through the center tomorrow and see if there is heat
damage.
 >  >
 >  > Cheers,
 >  >
 >  > Terry
 >  >
 >  >
 >  >
 >  >
 >  >
 >
 >