RE: Re-winding a NST

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

Original poster: "Pete Komen by way of Terry Fritz <twftesla-at-uswest-dot-net>" <pkomen-at-zianet-dot-com>

Hi Shad,

Maybe someone can correct me if I am wrong but I don't understand why you
multiply 8*38 to get primary turns.  If the NST primary (the secondary in
your test) is giving 38 volts using 1 volt per turn input, wouldn't the
primary be 38 turns?  The equation to solve is  8t/8v = xt/38v  xt (the
number of turns) is 38.  About 3.16 volts per turn figuring 120 volt input
to the NST primary.  I don't know if 3 volts per turn is feasible and I
don't want to dig into my physics book which may or probably not tell me.

Why not hook the NST primary to 120v and measure the voltage on your
temporary 8 turn secondary?

Regards,

Pete

-----Original Message-----
From: Tesla list [mailto:tesla-at-pupman-dot-com]
Sent: Wednesday, April 25, 2001 11:32 AM
To: tesla-at-pupman-dot-com
Subject: Re-winding a NST

Original poster: "sundog by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<sundog-at-timeship-dot-net>


Hi All,

  Some quick questions about rewinding this thing, so I get it right.

I'm using the original primary, but need to make 2 new secondaries for it.
It's a 9/30, and I have a 9/60 to do later.

with 8 turns of THHN wire on the core, with 8v into it, I get 38v on the
primary leads.

1 volt per turn means I have 8*38=304 primary turns.  Sound feasible?

Mkay.  At 9k output, I have 2 4500v secondaries in anti-parallel.  I got to
remember to wind them in opposite directions.

4500/120=37.5:1 necessary ratio for each secondary.  With 304 turns on the
primary, I end up with ~11,400 turns on each secondary.  I'm not concerned
with getting the voltage dead on, just in the ballpark.  I'm going to stick
as close as I can to what the manufacturers (9/30 is Magnatek, 9/60 is a
franceformer) originally had on it.  If anything I won't be able to get as
many turns as the manuf. and it'll have a lower output voltage.  I'm not
concerned with core saturation, as I won't be trying for more than 9kv out,
or feeding it more than 120v.  And if it does saturate, ahwell!

For potting!  I'm planning on using vaseline, possibly with LDPE melted in
with it.  I want to simmer the tranny in the gunk for awhile to give it a
chance to seep into all the airspaces it can.  HV oil is just too messy for
my taste, and I can't be bothered having to clean it up.  petroleum jelly
pretty much stays put once it solidifies.

I wanted to check and make sure I did the math right, so I don't spend an
hour or two working on it to end up with a "Doh!"

Along the same train of thought, I'd like to use 2 identical cores, wind
them with heavier wire to be single-ended (what's the technical tranny term
for a 1 eared polepig?) and run them back-to-back like MOTS for a mini-pig.
That's a project for another time tho.


Shad