St. Elmo Burgers


I've just been awarded a contract to build a 10KW+, vacuum tube 
powered, CW mode Tesla coil for a big commercial client.  This unit will 
operate at 100 KHz.  In anticipation of the contract I have already 
delivered a 33 kVA, three phase plate transformer and filter choke to 
the customers RF room.  I propose to build them a big PA based on a 
3CX10000D or 3CX15000D EIMAC transmitting triode excited by a variable 
frequency exciter oscillator which I have already built and delivered to them 
employing a single 833A triode.

A recent head-on highway collision has left me immobile for the past 
three weeks on rather strong painkillers.....um, hello?  If my posts 
have seemed a bit odd, this is why.  I am not yet well enough to do 
the travel and legwork to gather the parts necessary for their 
desired  big TC, but I luckily have parts at home stockpiled for a 
'someday personal project'  6 kW or more vacuum tube TC. I recently 
drug home two complete  RCA 10 kW AM broadcast transmitters (BTA10K)
and have lots'a neat high power RF parts.

The client has agreed, in sympathy for my temporary disability, to 
pay me to build my 6 kilowatt TC and use it on loan until I am well 
enough to build them 'the big one'.  I will retain ownership of this 6 kW 

This unit is beginning to take shape in my shop now.  4.3 kVA plate 
transformer will deliver about 4 KVDC with a cap input filter power 
supply. A dual gang 20 amp variac on the 230 volt single phase mains 
will control this transformer (this should be good for about 6-7 kW 
input DC to the oscilllator here at home in short duty cycle).  A pair 
of EEV BR1160 triodes (5kW plate dissipation each) in parallel will 
be employed.  I can get  5 kW out of a single one of these 
tubes, but I proposed to the client that when I delivered my 
temporary unit, I will hook it up to their much bigger plate 
transformer as an ouboard cluge and really push it.  I might get 10 kW out of my
system this way, so I've really got to overbuild it!

I hope to have this unit completed within 6 weeks and will let y'all 
know how my own 'Welding Torch from Hell' turns out.

This is definitely a neat project!

The resultant discharge will be a large Type 3.  Before I deliver it I propose to
hang a plastic tarp around the top terminal to protect the coil system from 
drips, and have a weenie roast using bamboo sticks!  We're gonna call 'em St.
Elmo Burgers!  I expect local fellow coiler Jeffrey Wiggins will be there.
All other coilers are welcomed too!  This party should be sometime in 
late September.  E-mail me personally if you think you can make it.  
I'm 40 minutes northeast of Oshawa, Ontario, near a little place called 
Janetville.  If this happens, my present pride and joy, MTC will be 
set up as well.  It'll be a kindof a Teslathon, with eats.

regards, rwstephens