[ARC5] Wow...12 to 24v converters

[Michael Hanz]

However...1.5 amps certainly is enough to keep the aircraft batteries 
floated: 1) between short transmissions, and 2) to continuously support 
a guard function for one of the receivers for fairly long periods of 
time.  The batteries would take care of startup currents and bridge 
momentary higher current draws.

I have no hard data on how this was done, only speculation based on 
individual equipment specifications.  But collectively they appear to 
form reasonable avenues of possibility, using a stock SCR-274N set as 
the given load.  Had I lived during the time and understood the live 
environment better, I have no doubt there would have been a way to do it 
without touching the 274N command sets themselves.  The "improvise, 
adapt, and overcome" mantra assumes accomplishment under the umbrella of 
understanding the larger environment - logistical, time, political 
constraints, and manpower.  It also assumes the need to do it quickly 
and with a minimum of complexity - pretty much an everyday engineering 
process, at least  in my experience.

- Mike  KC4TOS

On 8/1/2021 8:30 PM, Captain D. wrote:
> 25v 1.5 amps isn't going to cut it for the SCR-274-N.  Not near enough 
> amperage when the dynamotors are first fired up.
> Mark D.
> WW2RDO
> In a message dated 8/1/2021 6:22:51 PM Eastern Standard Time, 
> aaf-radio-1 at aafradio.org writes:
>
>     On 8/1/2021 3:23 PM, Hubert Miller wrote:
>
>         Fair Radio for some years sold a cubical box with something like 8 inches on a side,
>         that converted 12 DC to 24 DC. What was that thing for?
>
>     Not sure about Fair Radio, but there _was_ a 12 to 25v general
>     purpose supply made for aircraft use - the PP-18/AR, supplying up
>     to 1.5 amps output.  See attached data sheet and photo.  I've
>     never tired to bring it up, but the vibrators are sealed with
>     nitrogen, so there may be a chance for it working.  Note the
>     delicate correction of the input polarity errata.  😁
>
>     - Mike  KC4TOS
>


-------------- next part --------------
An HTML attachment was scrubbed...
URL: <http://mailman.qth.net/pipermail/arc5/attachments/20210801/e852f89f/attachment-0001.html>