Re: Idea for big VTTC

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

Original poster: "David Sharpe by way of Terry Fritz <twftesla-at-uswest-dot-net>" <sccr4us-at-erols-dot-com>

Crew, Carl
Making a power triode to handle 100kW is not such a stretch, particularly
when you consider David Sloan did exactly that in 1934 with his push-pull
VTTC unit which was used for X-ray generation.  Pulling the vacuum won't
be the problem either, with some intense scrounging, a used roughing and
turbo molecular pump can be had (Richard Hull has both and we have discussed
this same topic).  Where the problems will be are interface vacuum sealing,
HV hold off, and "getting" the residual ions out after you have high vacc'd the
"toob".  Getting the tantalum parts will be tough and expensive.  The epoxy
route mentioned earlier will get you NOWHERE, epoxy out gasses like a dog.

The real difficulty is that most experimenters don't have the power or space
to build such a large machine even with tubes.  A large VTTC system capable of
delivering 100kW to the tank will burn 20-30kW in the plates (+/- some).  The
filament power alone will be 2-5kW per tube.  Now you have to cool it with
cooling fans that look like air handing centrifugal blowers out of your
heat pump or
central air system (1500-3000 CFM), or cool it using deionized water or
oil cooling.  UHF 'Z' traps for such a monster becomes mind boggling, not
to mention crowbars, protective fusing, controls, or safety spark gaps.  What's
the size of a 1000 to 2000pF 30-50kV air variable capacitor or GLB unit??

I just installed a 30kW UPS, it occupied an electrician, his helper, and
yours truly
for 3 weeks pretty much full time.  With transfer switch and 460 to 120/208
45kVA
transformer, scope of the installation is at least close to same scale.
Now add
10-20kV at 5-10A into the tank.  What's the tank going to be constructed of, 1"
copper pipe or tubing???  It could be done, but you would need a dedicated
substation, a lot of space, experience working on HV/RF at high power, a
field of
high
power graveyard transmitter parts, and lots of US $$$$.

Regards
Dave Sharpe, TCBOR
Chesterfield, VA. USA

Tesla list wrote:

> Original poster: "by way of Terry Fritz <twftesla-at-uswest-dot-net>"
<Mddeming-at-aol-dot-com>
>
> In a message dated 3/19/01 7:49:06 PM Eastern Standard Time, tesla-at-pupman-dot-com
> writes:
>
> >
> > Original poster: "Drew Murray by way of Terry Fritz
<twftesla-at-uswest-dot-net>" <
> > drewallmighty-at-hotmail-dot-com>
> >
> > I was thinking about how one could build a really big VTTC or SSTC while i
> > was walking home from school today. the idea of building really large
> > semiconductors or big vacume tubes came upon me. Is it possible that if one
> > had a vacume pump and a vacume jar, could they construct a really big
> > vacume
> > tube for operation with a really big tesla coil. It would be interesting to
> > see the odd sparks produced by VTTC on a larger scale. Just an idea! Lemme
> > kow what you think.
> >                                                      Curious,
> >                                                      Drew Murray
> > _________________________________________________________________________
>
> Hi Drew & All!
>
> The tube you are looking for is an RCA 5770 Power Triode. It's about 24.5"
> long and 9.5" in diameter. It needs both water and forced-air cooling, but
> with 17KV DC on the plate, it can output over 100KW! I know they were in
> production 1949-1969, but I don't know about after that. If memory serves me
> (and it doesn't always), I believe radio station WABC-AM (770) (NYC)  used
> these through the early 1960s. I think one sold on eBay last year for around
> $500, but if you can afford the power to run it, you can afford the tube and
> the plumbing. Comments/enlightenment anyone?
>
> Matt D.