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Re: Spice simulation pictures
Tesla List wrote:
>
> > > Subject: Re: Spice simulation pictures
> Re: Spice simulation pictures
>
> >From rwstephens-at-ptbo.igs-dot-netFri Oct 18 22:58:41 1996
> Date: Sat, 19 Oct 1996 00:28:21 -0500
> From: "Robert W. Stephens" <rwstephens-at-ptbo.igs-dot-net>
> To: tesla-at-pupman-dot-com
> Subject: Re: Spice simulation pictures
>
> Date: Thu, 17 Oct 1996 22:25:01 -0600
> From: Tesla List <tesla-at-poodle.pupman-dot-com>
> To: Tesla-list-subscribers-at-poodle.pupman-dot-com
> Subject: Re: Spice simulation pictures
> Reply-to: tesla-at-pupman-dot-com
>
> > > Subject: Re: Spice simulation pictures
> snip
> >I eagerly await the first guy to have a 18"X4" secondary on his tube coil
> >with a 20"X5" toroid on top to step forward!!!!
> >
> >Richard Hull, TCBOR
>
> Richard,
>
> Would a 24 inch by 3 incher please you? Been there, done that. Oh
> BTW, no streamers.
Thats what I meant!!!.... Where's th' BEEF!!! R.Hull
>
> One important aspect characteristic of vacuum tube Tesla coils which
> is not often considered because it is not an issue with disruptive
> coils is the duty cycle of the circulating current in the secondary.
> Didn't someone (Bert?) recently post that the disruptive system has a duty
> cycle of some 0.03%? In a vacuum tube coil operating from a full
> wave filtered DC power supply the secondary circulating current is
> 100% CW RMS toaster watts power. At 100 kilovolts the resonator
> circulating current starts climbing rapidly as you add a little topload
> capacitance to your vacuum tube Tesla coil.
This is quite correct and why the toroid won't benefit a tube coil the
way it does the spark coil. The CW signal is why the tube coil will
never eual the spark system for arcs and sparks. R. Hull
>
> I made a 100pF cap which sustained 150 KV before
> breakdown from a 50 US gal steel drum and a smaller metal cylinder
> with rounded ends suspended inside. I wound a secondary out of #14 AWG
> enamelled copper wire on a 6 inch PVC form that resonated with this 'topload'
> at 150 kHz and drove it with my 1000 watt vacuum tube oscillator
> (3 x 810 triodes).
>
> I was able to swing the 100 pF load to about 85 kilovolts RMS (120 kV
> peak). The secondary winding got so hot in just 120 seconds of operation that
> I shut the system down for fear of melting the PVC tube on which it was
> wound! My circulating current was 8 amps RMS according to the
> measured output voltage across a capacitive reactance of some 10.6 K
> ohms, but the heat produced in the wire felt more the equivalent of
> maybe 30 amps RMS. Can anyone explain where my figuring leads to
> such an error? The interconnect between the top of the secondary and
> the drum capacitor was #14 PVC covered solid wire. It got bloody hot
> too. If I had had one then, that's where I would have liked to place an RF
> thermocouple ammeter.
>
> The commercial client who I am working on the large vacuum tube 100
> kHz system for with the oil filled resonator wanted me to consider
> also building them a system whereby I would be able to swing a 100 pF
> load to 200 KV RMS at 1 MHz. This is a formidable power challenge.
> Using the same figuring based just on voltage divided by capacitive
> reactance the continuous secondary resonator circulating current this time
> would be 125.63 amps RMS! This is a job only for large copper ribbon or
> tubing with silver plating. I declined on the big 1 MHz project BTW, at least
> until I get more high power CW experience. How about these guys with the
> vacuum tubes in the linear accelerators developing nearly three
> quarters of a megavolt at 50 MHz across a ten turn helix with a 50 kilowatt
> tube oscillator. At least they don't have to swing a big toplaoad capacitance.
>
> Food for thought, and actual projects for the well funded mentally deranged.
>
> rwstephens