On Fri 4 Jan 2002 John Ogden wrote:
>One more comment on why people run high plate voltages could be that they
>don't have very stiff power supplies. Like I stated in the earlier post
>that my supply drops from about 6KV to 5.2 KV under load. One could
>probably do better than that with more filter caps, larger gauge AC mains
>wire, etc.
There are a number of factors that effect voltage regulation the 2 most
important are IR drop of the transformer windings and the Permeability of
the core. The size of the capacitor bank has minimal influence on
regulation. An L Network with a choke input and small capacitor bank will
provide far superior regulation to a large stand alone capacitor bank all
things being equal. L Networks pose other problems though, specifically as
it relates to solid state rectifiers.
A couple of years ago W7CW built up a YC-156 amp. He came up with a very
"hefty" pole-pig transformer for the plate supply. Rectified it and fed it
straight to a capacitor bank and dropped 50 volts from 0 to 1 amp at 3300
volts. What provided the excellent regulation was the iron, in this case
the transformer.
> There's probably worse designs out there as well. So if you
>don't have a good power supply design, you could easily be under 5 KV under
>load.
73s
Bob K1TA
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