Re: 833A problems

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

Original poster: "Steven Ward by way of Terry Fritz <teslalist-at-qwest-dot-net>" <srward16-at-hotmail-dot-com>

Hi Dr,

Well, as it turns out, i managed to move all of the transformers far enough 
out of the way to get rid of this problem.  I found another smaller fil 
supply, so this helped the move in that i have both transformers in one 
side of the 12x18" 2 level setup. Surprisingly, the 2 big transformers, 
weigh about as much as an single 15/30 NST!  So the coil probably weighs 
about 40 pounds all together, really not bad at all. I would consider the 2 
box design, but its already set up, and besides, i need to use 2 variacs to 
control things.  Since my line voltage is about 130V at all times, i need 
to turn down the fil supply as it is exactly 1V too much. And then of 
course i need the 20A variac to control the plate.  Overall, the coil is 
pretty well tamed now that i made an adjustable grid coil.  It hapily makes 
some 24" sparks now, so efficiency is slowly getting better.  28" would 
look pretty nice, but i think that 32" is the max for 2 833A tubes.

I cant wait to show off this coil at the next teslathon.

Also, you dont use DC for your tube coils do you???  I hear that AC is much 
better at making long sparks, since the duty cycle is 1/2 of filtered DC.
That way, you can have a higher power envelope delivered to the secondary.
And the sparks look more interesting with the AC.

Steve Ward.




>From: "Tesla list" <tesla-at-pupman-dot-com>
>To: tesla-at-pupman-dot-com
>Subject: 833A problems
>Date: Mon, 20 Jan 2003 17:00:18 -0700
>
>Original poster: "Dr.Resonance by way of Terry Fritz 
><teslalist-at-qwest-dot-net>" <resonance-at-jvlnet-dot-com>
>
>
>Steve:
>
>You might consider a departure from normal VTTC design.  Put the HV power
>transformers in a separate enclosure under the display table.  Use NST GTO
>wire to route the HV up to the oscillator circuit which contains the tube,
>caps, inductors, etc.
>
>This helps a lot in transport also as carry the power xmfr "power pod"
>separately is a lot easier than having in contained with all the other
>oscillator components.
>
>A short 3-4 ft. long cable does the HV DC and AC fil. transfer work.
>
>Good luck with your coil.
>
>Dr. Resonance
>
> > Oh, about the insulation problem, thats all over now :)  The coil needed
> > better tuning, and a more adjustable grid coil.  Now its happily sprouting
> > 22" sparks:)  My next problem deals with induction heating.  Im using
>metal
> > brackets to hold the primary down.  They get VERY hot.  Also, realizing
> > that, i need to relocate the MOT PSU.  Right now, is below the primary
> > pretty much in the center of the coil!!!  I didnt think about it!  That
> > could really be eating up some power!  and the MOT seems to get hotter
>than
> > it should in such a shot amount of time (although its supplying some 2kw!)
> > So after these problems are solved, i should be seeing some really nice
> > sparks, as if the 22" was not already impressive.
>
> > Steve Ward.