[Milsurplus] 24V power supply project question

[jcoward5452 at aol.com]

Thanks George,
  Several have suggested a series diode for each supply and you suggest 
bringing the sense lines for each supply out to the load.This all seems 
to be good practice.There is no current limit control,only voltage over 
a small range.Although I think these supplies are self protecting and 
probably have fold-back current limiting for disastrous situations.
 Jay

-----Original Message-----
From: gl4d21a at juno.com
To: jcoward5452 at aol.com
Cc: milsurplus at mailman.qth.net
Sent: Tue, 17 Oct 2006 1:53 PM
Subject: Re: [Milsurplus] 24V power supply project question

Jay:

If those supplies include current limiting or constant current
capabilitites, direct parallel connections should work.  There was a
Hewlett Packard Application Note on paralleling regulated supplies
published back when they were drawings on cave walls made with a lump
of coal which discusses all the parameters.  Simplistically, it goes
like this:  Simple paralleling will result in the one supply which
has the highest output voltage becoming the primary, and as it
reaches current limiting, the output voltage drops a few millivolts
and the next starts to pick up part of the load, and so on through
however many supplies there are.  Separating the sense connections
from the individual outputs is required to make the supplies share
the load equally, but you will have to find the App Note to get the
details, as all my cave walls got scrubbed clean a few years ago.

In any event, parallelling supplies, even dissimilar ones requires no
magic, just a little understanding of Ohm's and Kirchoff's laws.

73,
George
W5VPQ


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