Thanks to all that responded with info and ideas. All good stuff and
things to think about. I am learning a lot from these discussions.
However, there seems to be a trend towards "design excellence" which I
cannot justify. This is for a amateur radio HOBBY application, not for
medical electronics, manned space flight, or government funded weapons
systems. Been there, done that, and retired from it! It ain't no fun for
this guy anymore.
I am striving to return to my roots, if you will, where all my equipment
was built from stuff I found in trash cans around the neighbor hood.
I.E., free or cheap.
Specifically what are the requirements for a switch mode power supply
for my application? Well, my days of dragging equipment around the world
are over, so weight is not an issue at all. I have cheap electricity so
efficiency is really not an issue either. Size is not much of an issue
although with four HV supplies taking up real estate in the shack now,
it would be good to combine two or more into one, hence the multiple
output selection mentioned earlier. Power factor correction? Why bother?
No matter what, it will be better than the HVAC unit on the house. (and
so will the start up surge)
Typical amateur conventional HV supplies run in the 10% to 20% output
voltage regulation from bleeder current to full output current, and they
are mostly at the 20% end rather than the 10% end of the scale. Output
ripple at 120 Hz is typically in the area of 1%. A switch mode supply
need NOT be any better than this. It may be an interesting design
exercise, but it just not required for typical ham radio work,
especially not mine.
The designs offered so far show me no advantage at all over a
conventional HV supply in terms of cost and usefulness. More over, I
will never consider anything with a control loop. Just call me stubborn
and let it go at that.
So far the cores mentioned have been, for me at least, made from
unobtainium. I have access to Micro-Metals, Fair-rite, and Steward cores
though the suppliers I normally deal with. It would really be nice to
see designs using materials made by one or more of those companies.
The challenge as I see it is not to produce an "excellent" design but to
come up with a 750 watt +/- module that can be built from a minimum
count parts list comprised of components that can be obtained at swap
meets and/or surplus houses as much as possible. Parts lists that total
up to the cost of a new Dahl/Harback transformer are not interesting to
me and I suspect not many others either. Think disposable consumer
electronics like microwave ovens and not Super Collider projects.
I suspect this won't go anywhere, but I need to ask....
Thanks & 73,
Larry - W7IUV
DN07dg
http://w7iuv.com
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