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Hi All,<br><br>
A mate just gave me a pair of power supply units out of a Dell PowerEdge
Blade Rack Server.<br><br>
The point of interest being that DC is generated at an intermediate rail,
and regulators local to the CPUs convert to the much lower required
voltages. This saves on I2R losses associated with carting high currents
around the motherboard.<br><br>
Given that the intermediate rail in question is 12 volts this could be
useful. Not entirely sure what to do with the associated 77 amps, but
that should fix the occasional current limit that my 12V / 25A psu
hits.<br><br>
Below are some notes sent to the fellow should they be of
interest.<br><br>
'Re-purposing' is such a PC phrase, so maybe this should be
re-porpoising, since I had a whale of a time...<br><br>
-Mark<br><br>
<blockquote type=cite class=cite cite="">Hi Andrew,<br><br>
Thanks for the two Dell ASTN 7000245 SMPSUs; one worked, the other was
DOA - it was disassembled to explore the design. Here are some
notes:<br><br>
<b><u>Power Inlet</u></b><br>
The power inlet is of type IEC 60320 C20, which mates with the IEC 60320
C19 power cord ( Jaycar,
<a href="http://www.jaycar.co.nz/productView.asp?ID=PS4180" eudora="autourl">
http://www.jaycar.co.nz/productView.asp?ID=PS4180</a> , $24 with trade
card).<br><br>
The associated Jaycar NZ wall plug isn't what it seems, the ground blade
is about 40% wider than usual, so will not go-in-the-hole without
filing.<br><br>
Disassembly of the PSU guts is non-trivial, I would not recommend trying
to replace the plower inlet something more available like the IEC 60320
C14.<br><br>
And of course Wikipedia has details of the IEC60320 spec
<a href="http://en.wikipedia.org/wiki/IEC_60320" eudora="autourl">
http://en.wikipedia.org/wiki/IEC_60320</a> (was IEC 320).<br><br>
There is a green indicator near the power inlet indicating active
AC.<br><br>
<b><u>DC output</u></b><br>
There is quite a community out there who use these units to charge
batteries for R/C applications, with a photo of the 3 pins than need to
be linked to enable power
<a href="http://www.rcgroups.com/forums/showpost.php?p=17653072" eudora="autourl">
http://www.rcgroups.com/forums/showpost.php?p=17653072</a> <br><br>
Sites include
<a href="http://www.helifreak.com/showthread.php?t=361840" eudora="autourl">
http://www.helifreak.com/showthread.php?t=361840</a> I am amazed /
impressed / appalled with the ingenuity of the enclosure <br><br>
Outputs are floating, so they can be wired in series, should you need 24,
36 or 48V at 77 amps (!)<br><br>
There are a couple of indicators by the handle showing DC available and
DC enabled.<br><br>
Output connector is a 'real one' (rather than a massively wide PCB
connector with gold fingers).<br><br>
<b><u>Design</u></b><br>
It is obviously worth waiting some time before poking around inside a
recently powered up Kilowatt PSU (!).<br><br>
All a bit jammed-in-the-box, so exploring the busted unit took a couple
of attempts to untangle some internal wiring looms - these were bent
around heatsinks and there is a PCB mounting screw hiding under the AC
power inlet (still haven't figured out how to get at it easily).<br><br>
The dual redundant PCB you gave me had a an I2C selector on it, so I was
expecting the some associated instrumentation inside the SMPSU units
(output current, voltage etc), but no sign of any ADCs which rather
surprised me (similar SMPSUs did have SDA and SCL brought out).<br><br>
Output heatsink is a blown rectangular tunnel of copper sheet with TO-263
power devices (Schottky rectifiers) soldered to it and a flat extruded
heatsink attached using (something like) epoxy putty. Outputs capacitors
and toroidal output chokes are also within this tunnel. Force air cooling
of capacitors is becoming less alien to me the more often that I see the
practice...<br><br>
Conversion efficiency appears to be quite low ( I have seen quoted
figures in the ~85% arena), this seems typical of SMPSUs of this
vintage.<br><br>
Fan noise is tolerable, given their large-ish size, and relatively slow
speed (same can't be said for 1U PSUs I have played with).<br><br>
<b><u>Overall</u></b><br>
Like similar PSUs, not really reparable, hence the desire to have a
couple spare units.<br><br>
Lots learned from this exercise, please put any similar designed units
aside to be poked at.<br><br>
Regards,<br><br>
Mark</blockquote></body>
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