Re: 5MV, 15/120mA Tesla Coil

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

Original poster: "Dr. Resonance" <resonance-at-jvlnet-dot-com> 


You are referring to the Breit, Tuve, and Dahl coil made in the late 1930's.
I met Greg Breit, retired Prof. Emeritus, at the UW-Wisconsin, and discussed
the coil with him.  They used the coil to accelerate electrons to high
energy levels to produce X-rays but the system proved so unreliable and
unstable it was later abandoned in favor of large Van de Graaffs.

Their original claim was 5 MEV but it was latered discovered it was only
close to 1.25 MEV in oil.  Their sparkgap system of measurement was totally
off.

Dr. Resonance

Resonance Research Corporation
E11870 Shadylane Rd.
Baraboo   WI   53913
 >
 > I seriously doubt they were even close to 5MV.  There are problems with
this
 > that are blatantly obvious.
 >
 > 1.  If this was a classic magnetically coupled tesla coil, that kind of
 > voltage could never form on the discharge terminal (topload) of that
 > secondary without
 > first striking over to the primary at a much lower voltage.
 >
 > 2.  The topload would have to be absolutely huge to allow that kind of
 > voltage to build-up.  Small toroids would have a much lower break-out
 > voltage and there would be
 > a discharge at a much lower voltage that obtainable.
 >
 > 3.  Also, with only 120mA at 15kV, there is not enough power available to
 > get 5MV in a single discharge cycle unless you were
 > charge pumping a topload capacitor or similar over many cycles.  The gain
is
 > approximately = 333 which is ENORMOUS!
 > Since Gain = SQRT (Cp/Cs) the secondary capacitance (self-capacitance of
 > secondary + topload capacitance) would have to be approximately 110,000
 > times
 > smaller than the primary capacitance!  Considering you new a large topload
 > to begin with to allow the voltage to build-up that high, you would have a
 > very large
 > primary capacitance and a 15kv/120mA transformer would NEVER be able to
run
 > that.
 >
 > I may be wrong here, but I think even the largest pole transformer tesla
 > coils (>30kW) would have trouble getting to 5MV output!
 >
 >
 > Dan
 >
 >
 >  > I read somewhere a few years ago on the TCBA newsletter (I think) about
a
 >  > team of coilers (pro physisicts? can't remember) that made an 8"x40"
 >  > secondary with ~7000 turns of 42 awg. They managed still to get 5
million
 >  > volts out of it with if I remember right a 15/120 supply. I take it
that
 >  > higher voltage doesn't necessarily mean longer spark, but am I
overlooking
 >  > something else? I don't think they mentioned the output length, but 5MV
is
 >  > hard to picture short.
 >  >   What if I keep the primary inductance high and add a bigger topload?
 > This
 >  > was my original idea, but was thinking that adding a breakout point
 > reduces
 >  > the effective capacitance, or does it do the equivelent of making it a
big
 >  > leakier capacitor? Can't test this without my scope and kinda chicken
to
 > try
 >  > since it's not a robust tube unit.
 >
 >
 >