I am trying to breathe life into an old HF amp (details below). It used 220
3 phase power originally and I am wondering what use I can get from it's
combined screen grid and bias power supply transformer. The transformer
primaries are for 220/440, and are currently wired up for the 220 use.
Primaries are delta, and both secondaries are Y - one marked 800V and one
marked 450V. Filters appear to be choke input.
As a test, I isolated one of the delta primary legs and fed it 110VAC while
monitoring the DC on the filter caps and looking for smoke. No smoke and I
get about 450VDC (unloaded) on one filter cap and about 225VDC on the
other. Looks pretty encouraging to me - maybe when I apply 220VAC I will
get roughly normal voltage from this thing.
Anybody have any advice on what I might run into in trying to use this
supply on single phase? I realize DC filtering would not be up to original
performance as-is, and I assume that the single leg primary might be
overloaded if I draw full current from it, but it was probably originally
rated for 24/7 CCS, so it might survive OK as is. If not, is it possible to
apply power to another of the delta primaries with my single phase power in
some way to spread out the load?
Ideas?
Oh - one more question - the plate blocking caps are rated at 8KV. Can I
guess the designed plate voltage from this?
Jerry W4UK
More details on the amp for those who like to read _long_ posts:
Made by TMC (Technical Material Corp). Model RFTA-1 . RF deck uses a
5CX3000A, along with smaller tubes in lower power drive stages, which I
probably won't use.
The PA tube's filament transformer, as well as the blower, are single phase
220V, so no problems there (thank goodness, because the tube uses 9V at 41
amps for the filament!).
I don't have any docs of any kind - no schematic. Tried several souorces
years ago when I got this thing and couldn't get any info back then.
Panels are green. I was told this was a NATO color, and this amp was
probably used in a HF point-to point NATO station.
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