RE: Ballast, first test.

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>

I put together some stuff I had in my shed for a test, with one 500ft
roll of 12ga and as many 8" pieces of elec fence wire I could bundle in
the center of the roll, the transformer pulled over 10 amps at about
200v, just starting to spark a 8 tube gap .256 total gap. I added the
NST primary in series with the roll of wire. It now pulls 7 to 8 amps at
220 to 240V. The transformer has a 55uf 480V run cap across the primary.
I guess I can bolt things in place and start putting more of the coil
together. I have a AC panel meter in the set up but it is 10 max and it
went over that on the first try.

Rich


Subject: Re: Ballast ?

Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>

Hi Rich,

Are you sure the transformer doesnt have any builtin ballast.  You
can verify this using a variac driving the transfomer with secondary
shorted. Start low on the output voltage of the variac and plot
current vs voltage to see if it is as expected.  If the slope is
correct then take it up to where the transformer primary current is
150ma * turns ratio.  If you get full 240Vac at this current level,
the transformer is already ballasted.  Just start out low and slow
until you feel comfortable going to a higher voltage.

Gerry R

 >Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>
 >
 >Hi Gerry , it is junk as a NST , I had to remove a few windings on one
 >side to get continuity but the other side took half the windings to
get
 >a reading so its scrap unless I use the primary core for a ballast , I
 >don't know all the electrical rules but here is a roll of 10ga wire
with
 >an iron core , not much different from a roll of wire from home depot
 >with welding rods in it.
 >I need ballast on 240v, I have a transformer that requires 240v
primary
 >, secondary is 13Kv, no MA listing on the tag but it is 1.95Kva so
that
 >come in about 150ma. It should be about 8amps of 240v and all will be
 >OK.
 >  I need a way to control the current if I use it with a Tesla Coil. I
 >don't want to run a resistor as a ballast. I did test the transformer
 >with some high wattage 240v quartz bulbs as a ballast and made a
Jacobs
 >ladder but I read an inductive ballast is better. It is all trial and
 >error at this end but I hope I only see sparks out of the coil and not
 >the power supply.
 >
 >Rich , from the middle of Missouri
 >
 >Subject: Re: Ballast?
 >
 >Original poster: "Gerry  Reynolds" <gerryreynolds@xxxxxxxxxxxxx>
 >
 >Hi Rich,
 >
 >The ballast use probably wont work on 240 since the NST was designed
 >for 120 in terms of core satuation.  Two in series might work
 >depending on what current you are after.  You might try to melt the
 >tar in an oven.  Often this will reflow any carbon tracking and
 >restore the NST (assuming that is what's wrong).  Also, you could
 >remove the tar and guts, clean it up, find what's wrong with it and
 >fix it, and then make a case to emerse it into oil (no more fragile
NST.
 >
 >Gerry R.
 >
 > >Original poster: "Rich & DJ" <rdj@xxxxxxxxxxxx>
 > >
 > >I have a Jefferson/Magnetek transformer, 15Kv 60ma, 120v primary..
 > >The secondary is bad,  it has some nice 10ga wire for the primary.
 > >  Would it be possible to use just the primary as a ballast on 240v
 > > , with out the secondary?
 > >This unit has no removable shunts for adjustment that I can see.
 > >
 > >Rich
 > >
 > >
 >
 >