Jim Isbell,
Seems like a good idea to me. I haven't thought out all the odds and
ends, but we do this at work, we have 30 kV DC (@30 Amps)
transformers outside, with FW rectifiers in the same oil tank. Then
we bring the pulsating DC through two cables to the capacitor room,
and crowbar system. This is fed to the load through a separate DC
cable. It is also done in a lot of TV transmitters using klystrons,
although i think they have the capacitors and the Trans/rectifier off
in tanks or enclosures.
It does eliminate having all that stored energy in front of the
cables, and put it at the load end where its really needed and has
lower impedance for the RF system.
John
K5PRO
In the first design I was going to bring the 6500VDC power through a
cable to the linear. But then it occurred to me that since the main
reason for the separate supply was the size...which is MOSTLY the 12KVA
transformer I am using. It might be safer to just make the transformer
external and have the rectifiers and filter capacitors in the
transmitter case thus allowing the only the transmission of AC, at a
lower potential, (using a voltage doubler circuit) in the cable. Thus,
by just turning off the input power I could eliminate the potential on
the cable instantly...or almost so...while the filter capacitors which
are the biggest danger would be in the transmitter cage and would be
connected to shorting circuits controlled by the safety switches on the
lid of the transmitter.
There must be some reason this is not a good idea as I have never seen
it done.
Any comments???
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