Re: BIG VTTC project

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

Original poster: "Andy, KB3EWY by way of Terry Fritz <teslalist-at-qwest-dot-net>" <kb3ewy-at-rcn-dot-com>

Greg,

I can't comment on the 4-1000 directly, I have a YU-204, which is the same 
spec-wise as the 4PR-1000A, pulse rated.  Mine is rated for only 1000W 
plate, 10KV plate and like 2 or 3 KV grid?  The power supply for my VTTC is 
two MOTs in series without ballasting or voltage doubling, although i'm 
sure a single MOT with voltage doubler would work (never could get those 
diodes from burning up).  Anyway, I had to supply voltage to the screen 
grid, I just used half of the plate supply for this through a 50W 40K power 
resistor. So the screen and control grid do not get tied 
together.  Although this was with a slightly different tube, this may not 
be required on a tube that was designed for a lower voltage.  (yours: 3KV, 
mine: 10KV) The filament supply was a core from a 15/30 NST that went 
bad.  Saved the primary for it and wound another secondary.  Use heavy wire 
for it though, 22A.  I managed 7" arcs my first time out.  Cp was 500pF 
30KV doorknob, Grid(C) was 500pF 30KV doorknob and!
  a 100W 10K variable power resistor.  Primary was 50 turns on a 3" PVC 
form.  Secondary was 1000 turns #32 on 2" PVC.  Grid coil is 20 turns on 
small 6" PVC.  24" arcs should be reasonable for this tube, especially 
running two of them in parallel!  See my webpage for more details.

Andy C.
http://www.hot-streamer-dot-com/kb3ewy


Andy C
Internet Homepage: http://users.rcn-dot-com/tcobaugh/
Amateur Radio Call: KB3EWY
AIM SN: KB3EWY