Re: Interesting thing about Tube Coil oscillators...

["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>

Hi David! 

This type of oscillator is known as a Meisner Oscillator in that the 
LOAD is resonant.  To increase your power into the resonator, the 
coupling as Bert (Hi!) mentioned earlier should be maximized.  Since 
you don't have two resonant circuits beating, you could couple up to 
0.6 or more and not have frequency splitting.  0.5-0.6 is about maximum 
you'll get with air dielectric, I've pushed magnifier couplings (driver primary

and secondaries) in excess of 0.62 using flux concentrators.  You're 
big problem will be voltage standoff, not maximizing the coupling coefficient. 

Regards 
Dave Sharpe, TCBOR 
Chesterfield, VA. USA 
>
>   
> > 
> > Original poster: "David Trimmell by way of Terry Fritz 
> <twftesla-at-uswest-dot-net>" <davidt-at-pond-dot-net> 
> > 
> > Hello all, 
> > 
> > I was doing some testing of various VTTC configurations last night, and 
> > thought I would try a "tankless" configuration. Running the output from 
> > the Level Shifter (normally the B+, but in this case we are using the tube 
> > to self-rectify HV AC) into the base of my solenoid Primary (23 turns of 
> > PVC insulted #12 on 6" form 79uH measured), the top of the primary was 
> > connected to the plate of a single 833C. Grid coil with 22 turns of PVC 
> > insulted #22 wire is 3/4 inch above secondary, with 4 to 25 K resistance 
> > for bias, 0.001uF mica cap in parallel. Using this configuration the coil 
> > will oscillate, producing 3-4" discharge with 4800V on the plate. Power 
> > consumtion was high ~25 Amps from wall at 40 volts into the PT (60:1), but 
> > grid current was low, even with only 4 K resistance, less then 30 mA. It 
> > is quite intesting how I can get a coil that is self resonant at around 
> > 380KHz to produce this discharge. I am asuming the parasitic capacitance 
> > in the primary is working here? BUT that would put the Fr0 in the many 
> > Megahertz range!? 
> > 
> > Anyone have agood explaination of what is really going on here? 
> > 
> > Regards, 
> > 
> > David Trimmell 
>