Re: Reason why DC mag field disturbs communications on a train

Guy Macon wrote:

Jamie wrote:

Guy Macon wrote:


Jamie wrote:


the 100Khz is coming form the 350KW oscillator tube that generates the
AC required in side of a gas pressured vessel where walt Crockcroft multiplier is employed that can yield up to 5Mvolts.

You have to love those Cockroft-Walton voltage multipliers; no
single component has to withstand the entire output voltage.

Did you know about the trick of using larger capacitors (or same-size
capacitors in parallel) in the lower stages to reduce output ripple?


Yes, and I don't see where that is a trick. I thought that was common?


It probably is, but I have seen physics students build them from
the original 1951 paper by James D. Cockcroft and Ernest T. S. Walton with equal value capacitors. I probably should look up the
original paper and see if it mentions larger capacitors near the bottom of the stack.



You can place the final cap to common at the end if you can find one that can handle the voltage.. I don't think a 5Mv one exist. I could
be wrong there !. :)

In any case, we wouldn't be able to energize the heater in the beam
tube at the end of the HV stack if we didn't have a ripple in it. Its
funny how a hindrance actually aids the design in other ways.

100Khz was selected in the design so that low value cap size could be
used along with litz wire pie RF xformers.

The oscillator design is a armstrong type. Tickler coil is actually the plate coil and feed back coil which sits in the pie rack assembly as part of the feed back tanked with some caps to select the 100 Khz freq.

The heater in that tube takes aprox 260 amps at 12 volts AC to warm up.
Supply voltage is variable up to 15kV DC coming from SCR 3 phase firing stacks.


http://webpages.charter.net/jamie_5";

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