THURSTON ACKERMAN wrote in a message to ALL:

 TA> There has been some looking for 24vdc power supplies

Has there really?  What are they good for?

 TA> so I cast a holler to other OTs that seemed to remember a possible 
 TA> source as seen in the following:

 TA> ===================================================================
 TA> ========  BBS: Hafa Adai Exchange & BBSNetworks
 TA> Date: 12-14-03 (17:00)             Number: 2015
 TA> From: BOB KLAHN                    Refer#: NONE
 TA>   To: THURSTON ACKERMAN             Recvd: NO
 TA> Subj: NCO's, Education, and Mil      Conf: (307) Fido-Debat
 TA> -------------------------------------------------------------------
 TA> -------- 
FS>>-=> Quoting Bob Klahn to Frank Scheidt <=-

FS>> FS> During WWII I took correspondence courses from the U.S.
FS>> FS> Armed Forces Institute, commonly called "USAFI"
located in
FS>> FS> Madison, Wisconsin.  They offered a wide variety of
FS>> FS> subjects -- *not* including "Armorer, Aircraft"
... heh heh
FS>> FS> heh ...

 TA> Please pardon my intrusion here Frank but over on the Fido Tech 
 TA> Echo there is some discussion regarding 24v dc power supplies for 
 TA> PCs.

I was of the impression that what we were looking at was ways to run a pc
off a 12v battery,  but no matter.

 TA> Many moons ago I worked on military aircraft radio communications 
 TA> systems and my aged, defragged memory suggests many aircraft 
 TA> electric supplies were 24vdc.

I remember seeing some military surplus stuff way back when,  but I thought
it wanted something like 28v?

 TA> Is this a fact? If so might one find a surplus market one might 
 TA> procure some 24vdc power gear? Maybe on EBay or ?

 TA>  Aircraft used 24VDC when I was in '67-71.

Worse yet,  it wanted 400 cycles!

 TA>  Try Fair Radio in Ohio, or that place out in Omaha, which I will 
 TA> think of as soon as I send this off.

Fair Radio sure has some interesting junk.  :-)

 TA>  Industrial power supplies are also commonly 24VDC. So you can 
 TA> check almost any industrial electric supplier.
 TA> ...

Are they really?  Hm.

I have one here,  a *big* one,  rated at something like 10A output.  Dunno
what I'm gonna do with it yet.  It was apparently a part of a telephone
system at one point,  as that's what else was out there at curbside with
it.  Local kids picked up the phones to play with,  and the other thing was
the box that this PS plugged into,  I didn't snag that,  maybe I should
have.    It would have at least given me the mating connector for
the other end of this cable that's attached to this thing.

It's got a big ferroresonant transformer in there,  an extra winding or
two,  apparently some provision for battery backup which isn't implemented,
 and I can't recall what else.

I also have a whole mess of 24v and 48v relays,  from some earlier salvage.
 Apparently that was phone equipment as well.  I guess the higher the
voltage, the less you have to worry about losses in the wires -- double the
voltage and you halve the current,  and you cut your I-squared-R losses by
a factor of 4...

I know thermostat wiring uses 24v,  phone systems use 48v,  don't know what
else would use stuff at this level...

You guys have any ideas as to what this might be good for?

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