[time-nuts] Where does 28V come from?

Roy Phillips phill.r1 at btinternet.com
Tue Jul 21 11:04:52 UTC 2009


Hal
I think you will find that 28 volts DC is standard in many aviation and 
military mobile equipment power requirements. It is the nominal battery 
voltage that comes from two 12 volt cells in series that are fully charged. 
The voltage to run such equipment is not critical (can be less than 28 
volts), as you normally charge two series 12 volt cells at 27.6 volts - this 
is indicative of the nominal voltage of such supplies. Trust that this is 
the information you are looking for ?
Roy Phillips.

----- Original Message ----- 
From: "Hal Murray" <hmurray at megapathdsl.net>
To: "Discussion of precise time and frequency measurement" 
<time-nuts at febo.com>
Sent: Tuesday, July 21, 2009 7:59 AM
Subject: [time-nuts] Where does 28V come from?


>
>> That said, the modules also appear to be powered by 28VDC, add some
>> regulation, you could use the chassis to power the Thunderbolt, and
>> mount it in one of the blank panels.
>
> Lead acid batteries are close to 2V per cell.  For cars/trucks, they come
> conviently packaged in 6V and 12V units.  The phone company works off 48V.
>
> But where does 28V come from?
>
> The Isotemp OSCO 127-10 data sheet says 27 V, but that's +3, -6 or 21-30V
> which straddles both 24V and 28V.
>
>
> -- 
> These are my opinions, not necessarily my employer's.  I hate spam.
>
>
>
>
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