[AMPS] auto transformers

Peter Chadwick Peter.Chadwick@gpsemi.com
Mon, 17 Nov 1997 11:16:41 -0000


Bob,

I wouldn't go so far as to 'never use' an autotransformer. If you do, it
needs to be suitably rated - that means BIG and HEAVY. The existing
plate transformer would be caned harder - more magnetising current
because of the higher primary voltage, so it would get hotter, and it
might hit core saturation if you go too far. Probably something like 10%
is as far as I'd go. If you plan RTTY or SSTV, then I wouldn't even push
it 10%.

Rich's comments are very pertinent on the taps and type of rectifier. 

Lane's advice is the best - change the xfmr.

You may be able to build another PSU -say 800 or 1000 volts at an amp or
so DC and series it up, but watch the transformer insulation. Or put in
a transformer of about that volts with the secondaries in series and the
primaries in parallel, but again watch the insulation.

The ARRL book says that you should 1300 odd watts in gg with 3Kv on the
plate.

Has anyone any experience of 3000 volt 1A switching type PSU's?

73 

Peter G3RZP

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