Re: Pressurized nitrogen tank capacitor for big VTTC?

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

Original poster: Terry Fritz <teslalist-at-twfpowerelectronics-dot-com>

Hi Scott,

I am sure these are like the pressure SF6 caps today.  They are just trying 
to raise the breakdown voltage while keeping the Q very high.  Oil and such 
adds loss, but just adding air....  This may have been before Joe Jennings 
figured out vacuum caps...

Cheers,

         Terry

At 04:31 PM 3/7/2004, you wrote:
>One of my dad's old industrial electronics books (Electronics for Industry,
>W.I. Bendz, 1947) has several chapters covering high power vacuum-tube
>oscillators for induction-heating applications.
>
>Shown in a photograph on page 247 is a 10 KW vacuum-tube oscillator
>featuring a "tank capacitor (pressurized nitrogen type with high voltage
>terminal at bottom)".
>
>This appears to be a metal cylinder about 10 inches in diameter by 12 inches
>long, with flat end plates, and a conventional 2" diameter pressure gage
>sticking out the top. Some sort of smaller cylindrical can is projecting out
>the bottom, that may be the high voltage terminal referenced in the text.
>
>The rest of the photo shows what might pass for the makings of a very large
>VTTC, with a giant air-cooled glass/metal triode, very large open frame tank
>coil, etc.
>
>But, what is a "pressurized nitrogen capacitor"?
>
>Does anyone have any insight into the internal construction, and the
>operating pressure?
>
>Web searches for "pressurized nitrogen capacitor" have yielded nothing.
>
>Regards,
>Scott Hanson