Re: Help please - info on big CDE pulse caps?

["Tesla list" <tesla@xxxxxxxxxx>]

Original poster: "Jim Lux" <jimlux@xxxxxxxxxxxxx>


>  >
>  >      The caps themselves are a reasonable 9" wide by 12" deep by 25"
tall,
>  > with a single 16" tall by 5" diameter insulator on top of that. Kinda
>  > heavy. Connection is via the terminal on top of the insulator and by
the
>  > case of the caps themselves (mounting flanges on the bottom and "ears"
on
>  > the sides of the case).
>  >      Ink on the sides reads:
>  >      "CORNELL DUBILIER ELECTRONICS
>  >      TKB 165
>  >      .15 MFD 120KVDC
>  >      50[degree]C MAX OPERATING
>  >      SERIAL NO. 109
>  >      MANUFACTURED FOR RCA SERVICE COMPANY
>  >      CAMDEN, NEW JERSEY, PER CEMCO
>  >      SPECIFICATION NUMBER 3079B
>  >      MODIFIED PER G-41839002-J31 DATED 17 JUL 1964"
>
>
>  >       If the ".15MFD" means .15 micro-Farads, then they are kinda big
for
>  > their energy storage.Perhaps the high voltage rating explains this
>  > disproportionate case size and insulator height.
>
> Yes, the 120 kV voltage rating is quite high and explains the
> relatively large volume vs uFd rating. Also, considering their
> date on manufacture, they are certainly not that big for their
> energy rating.
>
>   They are definitely
>  > oil-filled, and I am told by someone who dissected one that they have
an
>  > internal voltage-distribution network of resistors. One has been a tad
>  > leaky at the base of the insulator, but the leak is very thick and
> sticky -
>  > like molasses.
>
> Oooh, that sounds a lot like a PCB based dielectric, especially consi-
> dering that they were manufactured well before 1977. I'd try not to
> get any of that "molasses" on me :^O

Or, just old gummy oil..

These sound like DC filter capacitors (especially with the comment about
internal resistors). Perhaps for a transmitting or X-ray tube?  (After all,
RCA did make lots of high power microwave transmitters at one time).

50-100 kV wouldn't be an unusual voltage for a big klystron, for instance.
Or for a stage capacitor in a Cockroft Walton supply for a particle
accelerator.  Lots of those being built back in the 50s and 60s

Also, don't neglect the possibility that it's a one of a kind for some
special purpose.  Say you're a researcher who needs a 100 kV DC power
supply. You're not going to roll your own caps (literally).  Nope, you call
up a company who does HV work and have them make you a custom.  Not everyone
scrounges HV gear from ebay or surplus places. We just bought a very nice
1kV, 10 Amp power supply at work for running an experimental 5 kW solid
state transmitter.  As I recall, it was in the usual $1/watt range.