Re: MOT supply

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

Original poster: "Gregory Hunter by way of Terry Fritz <twftesla-at-qwest-dot-net>" <ghunter31014-at-yahoo-dot-com>

Mark,

The low voltage, high current approach you are
contemplating is workable, but it's a tough way to go.
I also think .75uF is an unrealistically large tank
cap value. I'd shoot for something more in the .1-.2uF
range.

If I get a vote, I think the voltage doubler approach
would make your life simpler. With 8kvac to play with,
you could use a simple sucker gap and still get
adequate quenching. You could also use a more sensible
tank cap size.

Wattage doesn't change when you use the doubler.
Voltage goes up, but current goes down, so the overall
power stays roughly the same. What the half-wave
voltage doubler will do for you is "save up" energy
for half a cycle, then dump it all at once in the next
half cycle. For a glorious half-cycle, the TC tank
"feels" like it's getting twice the juice! (That's my
half-baked theory, anyway). During "dead time", when
the doubler caps are recharging, the TC tank is shut
down for a whole half-cycle. This interuption of the
current virtually eliminates the possibility of
runaway power arcing with any sensible spark gap.

My $0.02

Best Regards,

Greg
http://hot-streamer-dot-com/greg

--- Tesla list <tesla-at-pupman-dot-com> wrote:
> Original poster: "by way of Terry Fritz
> <twftesla-at-qwest-dot-net>" <A123X-at-aol-dot-com>
> 
> I'm planning to build a TC with a 6" by 30"
> secondary wound with 22 awg wire. I
> was originally planning on using to MOT's in series
> ballasted by another MOT
> for around 1800VA at 4285v after a little voltage
> increase with a variac. My
> first problem is getting a meter to check how much
> power it is, then I was
> planning on using a pretty large cap size with an
> async rotary or a somewhat
> larger size of .75uf to be used with a sync
> triggered gap. I thought that these
> cap sizes might make tuning difficult. Would I be
> better off using a microwave
> oven style voltage doubler so I would have a smaller
> cap size, then not
> worrying about the exact power input, and going with
> the async rotary? I was
> wondering how much the wattage is increased after
> the doubling and does it
> double the voltage or increase it by more? 
> 
> Mark
> 
> 


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