RE: old fashioned 810 triode Tesla coils

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Hooper, Christopher AZ" <christopher.az.hooper@xxxxxxxxx>

Miles,

I built some super nice tube coils, the last is a Dual 833C VTTC pumping
30 plus inch
sparks @ http://users.cableaz.com/~chooper/images/sparks_1.gif

and full page @ http://users.cableaz.com/~chooper/833c_vttc_1200.htm.

This 2000 watt VTTC will light a garden tool on fire @
http://users.cableaz.com/~chooper/images/ww14.jpg

and http://users.cableaz.com/~chooper/images/ww16.jpg

A coil that still gets a great deal of smiles.....and runs and runs and
runs!


Cheers,
Christopher robin


-----Original Message-----
From: Tesla list [mailto:tesla@xxxxxxxxxx]
Sent: Sunday, December 18, 2005 12:45 PM
To: tesla@xxxxxxxxxx
Subject: Re: old fashioned 810 triode Tesla coils

Original poster: gary350@xxxxxxxxxxxxx

30 years ago I built a TC using an 810 tube.  It was a power
oscillator.  Power supply voltage was 2500 VDC  500 ma.  The tube is
rated 2500 VDC plate voltage 300 ma.    I had a few turns of wire
wrapped around the secondary coil driving the grid.  The output from
the secondary coil was about 4" long spark.  There were 1000s of
needle point blue sparks sticking straight out in all directions 360
degrees around the top of the secondary coil.  I never thought is was
a good TC.   I think the RF sparks are typical of this type of system.

Gary Weaver



-----Original Message-----
 >From: Tesla list <tesla@xxxxxxxxxx>
 >Sent: Dec 17, 2005 2:53 PM
 >To: tesla@xxxxxxxxxx
 >Subject: Re: old fashioned triode Tesla coils
 >
 >Original poster: FutureT@xxxxxxx
 >
 >In a message dated 12/17/05 3:40:41 AM Eastern Standard Time,
 >tesla@xxxxxxxxxx writes:
 >
 >
 >>Dear All,
 >>
 >>I am very interested in working out the details of a triode or tube
TC,
 >>because I want to compare this method to the newer solid state coil
 >>schematics. Can someone give me a pointer as to where I can find a
basic
 >>concept, basic schematic, or layout, for a triode driven interruptor
circuit
 >>that replaces the traditional spark gap?
 >>
 >>Sincerely,
 >>
 >>Miles
 >
 >
 >Miles,
 >
 >Tube Tesla coils as traditionally built do not use the tube as
 >a replacement for the traditional spark gap.  Instead the design
 >is actually a power oscillator coupled to a secondary coil.  They
 >run in continuous wave fashion except they usually run on raw
 >60Hz AC.  The continuous wave operation makes them much
 >less "efficient" at producing long sparks for a given input power
 >compared withspark gap coils.  I usually
 >include an interrupter circuit which permits a selectable number
 >of AC cycles to be skipped.  This gives the coil a pulsed or
 >"staccato" type behaviour.  This provides for interesting visual
 >and sound effects in a sense.  It also increases the "efficiency"
 >in a way.  Using this staccato pulsing method, the tube can
 >be run harder when it *is* on.  This results in longer sparks from
 >a given tube.  I show some of my work at my website at:
 >
 >    http://hometown.aol.com/futuret/page3.html
 >
 >I'm not sure what schematics I have at my website.  I had sent
 >some information to Steve Ward in the past and he may still have
 >some of this at his website, along with his own subsequent tube
 >coil work.
 >
 >Richard Hull of Richmond VA once built a tube coil which used
 >a hydrogen thyratron to replace the spark gap.  Unfortunately
 >this provided only for a one-way flow of current.  Thus he was
 >forced to terminate conduction at the first beat which prevented
 >a complete transfer of energy and greatly hurt the efficiency of
 >the system.  He probably could have added a diode across the
 >thyratron to conduct the reverse current.  He considered using
 >dual cross-parallel thyratrons but never got around to trying it.
 >
 >John
 >
 >