atec77 said:
I have two of the old telstra transformers here from when I started with
them about 30 + years ago and the tranny from a 150 amp dc tig , just
sold my 3.5kw 48 vdc supply , I have a copy of switchmode power supplies
spice and p so when time permits might build one
There is a Honkers bloke who does 350 and 400 watt supplies very cheaply ,
perhaps one of the blade server 48Vdc remote supplies will show up at a
fair price
You could link 4 ATX power supplies in series. You would have to open up 3
of them and cut the link between the negative terminal and earth.
It will be safe if you hard wire all 4 outputs together in series in a way
that they can not be disconnected. I think the only reason they earth the
negative output is so that it doesn't float at a high voltage WRT mains. So
if all your connections are good, the highest any output will float is 48V.
Modern ATX supplies typically have two 12V 20A rails. But many dont realise
that they are not actually separate rails. The rails are separately filtered
with caps, but come from a single SM transformer. (typically)
So each ATX supplies 12V at 40A. Cost is about $40 each from ebay, so $160
is your total.