Re: 5MV, 312kW

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

Original poster: Finn Hammer <f-h-at-c.dk> 

All,

To arrive at 5MV on the top, the toroid has to be the right shape and size 
to suppress breakout at lesser voltages.
It _could_ look like this in INCA:
* 5MVtoroid

Lcenter terminal 20 0 2 1.17 2
Cedge terminal 20 2 2 0.83 0 180
Cedge terminal 20 2 2 0.83 0 -180

and would then be :
Minor diametre: 1.66 metre (65")
Major diametre: 5.00 metre (196")
Chip in with 250pF of topload and
  3125 Joules of energy........

Running the coil below it, at 100BPS, would require 312.5kW

Let`s be bold, without being utterly rediculous, and charge the primary 
capacitor to 50kV, it will then have to be 2.5µF

Pairing this cap up in a tank with a primary coil that has 2 turns, 
starting at 70" diametre, 10" spacing and 15.6µH will make it ring at 25kHz.

All we need is a secondary that is 50" in diametre, 250"long wound at 3 
turns per inch.

Assuming 2nd. notch quench, and a coupling of 0.122, the energy will be 
transferred after 13 cycles/break, or a total of 0.052secs/sec. Ringing at 
5.2% of the time, there should be ample time to charge the cap btwn. bangs.

I`ve used INCA, ballpark numbers, and wintesla (Yeah, that`s right: the 
reg`d copy), for this brief design exercise which untill someone points out 
an order of magnitude error, suggests that a 5MV coil is not at all that 
unrealistic, not being concerned with the aspect of funding.

Cheers, Finn Hammer



Tesla list wrote:
>Original poster: dhmccauley-at-spacecatlighting-dot-com
>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.
>